discontinued / server · Files

index.html 314 KB
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715 1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145 2146 2147 2148 2149 2150 2151 2152 2153 2154 2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 2182 2183 2184 2185 2186 2187 2188 2189 2190 2191 2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203 2204 2205 2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219 2220 2221 2222 2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233 2234 2235 2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257 2258 2259 2260 2261 2262 2263 2264 2265 2266 2267 2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278 2279 2280 2281 2282 2283 2284 2285 2286 2287 2288 2289 2290 2291 2292 2293 2294 2295 2296 2297 2298 2299 2300 2301 2302 2303 2304 2305 2306 2307 2308 2309 2310 2311 2312 2313 2314 2315 2316 2317 2318 2319 2320 2321 2322 2323 2324 2325 2326 2327 2328 2329 2330 2331 2332 2333 2334 2335 2336 2337 2338 2339 2340 2341 2342 2343 2344 2345 2346 2347 2348 2349 2350 2351 2352 2353 2354 2355 2356 2357 2358 2359 2360 2361 2362 2363 2364 2365 2366 2367 2368 2369 2370 2371 2372 2373 2374 2375 2376 2377 2378 2379 2380 2381 2382 2383 2384 2385 2386 2387 2388 2389 2390 2391 2392 2393 2394 2395 2396 2397 2398 2399 2400 2401 2402 2403 2404 2405 2406 2407 2408 2409 2410 2411 2412 2413 2414 2415 2416 2417 2418 2419 2420 2421 2422 2423 2424 2425 2426 2427 2428 2429 2430 2431 2432 2433 2434 2435 2436 2437 2438 2439 2440 2441 2442 2443 2444 2445 2446 2447 2448 2449 2450 2451 2452 2453 2454 2455 2456 2457 2458 2459 2460 2461 2462 2463 2464 2465 2466 2467 2468 2469 2470 2471 2472 2473 2474 2475 2476 2477 2478 2479 2480 2481 2482 2483 2484 2485 2486 2487 2488 2489 2490 2491 2492 2493 2494 2495 2496 2497 2498 2499 2500 2501 2502 2503 2504 2505 2506 2507 2508 2509 2510 2511 2512 2513 2514 2515 2516 2517 2518 2519 2520 2521 2522 2523 2524 2525 2526 2527 2528 2529 2530 2531 2532 2533 2534 2535 2536 2537 2538 2539 2540 2541 2542 2543 2544 2545 2546 2547 2548 2549 2550 2551 2552 2553 2554 2555 2556 2557 2558 2559 2560 2561 2562 2563 2564 2565 2566 2567 2568 2569 2570 2571 2572 2573 2574 2575 2576 2577 2578 2579 2580 2581 2582 2583 2584 2585 2586 2587 2588 2589 2590 2591 2592 2593 2594 2595 2596 2597 2598 2599 2600 2601 2602 2603 2604 2605 2606 2607 2608 2609 2610 2611 2612 2613 2614 2615 2616 2617 2618 2619 2620 2621 2622 2623 2624 2625 2626 2627 2628 2629 2630 2631 2632 2633 2634 2635 2636 2637 2638 2639 2640 2641 2642 2643 2644 2645 2646 2647 2648 2649 2650 2651 2652 2653 2654 2655 2656 2657 2658 2659 2660 2661 2662 2663 2664 2665 2666 2667 2668 2669 2670 2671 2672 2673 2674 2675 2676 2677 2678 2679 2680 2681 2682 2683 2684 2685 2686 2687 2688 2689 2690 2691 2692 2693 2694 2695 2696 2697 2698 2699 2700 2701 2702 2703 2704 2705 2706 2707 2708 2709 2710 2711 2712 2713 2714 2715 2716 2717 2718 2719 2720 2721 2722 2723 2724 2725 2726 2727 2728 2729 2730 2731 2732 2733 2734 2735 2736 2737 2738 2739 2740 2741 2742 2743 2744 2745 2746 2747 2748 2749 2750 2751 2752 2753 2754 2755 2756 2757 2758 2759 2760 2761 2762 2763 2764 2765 2766 2767 2768 2769 2770 2771 2772 2773 2774 2775 2776 2777 2778 2779 2780 2781 2782 2783 2784 2785 2786 2787 2788 2789 2790 2791 2792 2793 2794 2795 2796 2797 2798 2799 2800 2801 2802 2803 2804 2805 2806 2807 2808 2809 2810 2811 2812 2813 2814 2815 2816 2817 2818 2819 2820 2821 2822 2823 2824 2825 2826 2827 2828 2829 2830 2831 2832 2833 2834 2835 2836 2837 2838 2839 2840 2841 2842 2843 2844 2845 2846 2847 2848 2849 2850 2851 2852 2853 2854 2855 2856 2857 2858 2859 2860 2861 2862 2863 2864 2865 2866 2867 2868 2869 2870 2871 2872 2873 2874 2875 2876 2877 2878 2879 2880 2881 2882 2883 2884 2885 2886 2887 2888 2889 2890 2891 2892 2893 2894 2895 2896 2897 2898 2899 2900 2901 2902 2903 2904 2905 2906 2907 2908 2909 2910 2911 2912 2913 2914 2915 2916 2917 2918 2919 2920 2921 2922 2923 2924 2925 2926 2927 2928 2929 2930 2931 2932 2933 2934 2935 2936 2937 2938 2939 2940 2941 2942 2943 2944 2945 2946 2947 2948 2949 2950 2951 2952 2953 2954 2955 2956 2957 2958 2959 2960 2961 2962 2963 2964 2965 2966 2967 2968 2969 2970 2971 2972 2973 2974 2975 2976 2977 2978 2979 2980 2981 2982 2983 2984 2985 2986 2987 2988 2989 2990 2991 2992 2993 2994 2995 2996 2997 2998 2999 3000 3001 3002 3003 3004 3005 3006 3007 3008 3009 3010 3011 3012 3013 3014 3015 3016 3017 3018 3019 3020 3021 3022 3023 3024 3025 3026 3027 3028 3029 3030 3031 3032 3033 3034 3035 3036 3037 3038 3039 3040 3041 3042 3043 3044 3045 3046 3047 3048 3049 3050 3051 3052 3053 3054 3055 3056 3057 3058 3059 3060 3061 3062 3063 3064 3065 3066 3067 3068 3069 3070 3071 3072 3073 3074 3075 3076 3077 3078 3079 3080 3081 3082 3083 3084 3085 3086 3087 3088 3089 3090 3091 3092 3093 3094 3095 3096 3097 3098 3099 3100 3101 3102 3103 3104 3105 3106 3107 3108 3109 3110 3111 3112 3113 3114 3115 3116 3117 3118 3119 3120 3121 3122 3123 3124 3125 3126 3127 3128 3129 3130 3131 3132 3133 3134 3135 3136 3137 3138 3139 3140 3141 3142 3143 3144 3145 3146 3147 3148 3149 3150 3151 3152 3153 3154 3155 3156 3157 3158 3159 3160 3161 3162 3163 3164 3165 3166 3167 3168 3169 3170 3171 3172 3173 3174 3175 3176 3177 3178 3179 3180 3181 3182 3183 3184 3185 3186 3187 3188 3189 3190 3191 3192 3193 3194 3195 3196 3197 3198 3199 3200 3201 3202 3203 3204 3205 3206 3207 3208 3209 3210 3211 3212 3213 3214 3215 3216 3217 3218 3219 3220 3221 3222 3223 3224 3225 3226 3227 3228 3229 3230 3231 3232 3233 3234 3235 3236 3237 3238 3239 3240 3241 3242 3243 3244 3245 3246 3247 3248 3249 3250 3251 3252 3253 3254 3255 3256 3257 3258 3259 3260 3261 3262 3263 3264 3265 3266 3267 3268 3269 3270 3271 3272 3273 3274 3275 3276 3277 3278 3279 3280 3281 3282 3283 3284 3285 3286 3287 3288 3289 3290 3291 3292 3293 3294 3295 3296 3297 3298 3299 3300 3301 3302 3303 3304 3305 3306 3307 3308 3309 3310 3311 3312 3313 3314 3315 3316 3317 3318 3319 3320 3321 3322 3323 3324 3325 3326 3327 3328 3329 3330 3331 3332 3333 3334 3335 3336 3337 3338 3339 3340 3341 3342 3343 3344 3345 3346 3347 3348 3349 3350 3351 3352 3353 3354 3355 3356 3357 3358 3359 3360 3361 3362 3363 3364 3365 3366 3367 3368 3369 3370 3371 3372 3373 3374 3375 3376 3377 3378 3379 3380 3381 3382 3383 3384 3385 3386 3387 3388 3389 3390 3391 3392 3393 3394 3395 3396 3397 3398 3399 3400 3401 3402 3403 3404 3405 3406 3407 3408 3409 3410 3411 3412 3413 3414 3415 3416 3417 3418 3419 3420 3421 3422 3423 3424 3425 3426 3427 3428 3429 3430 3431 3432 3433 3434 3435 3436 3437 3438 3439 3440 3441 3442 3443 3444 3445 3446 3447 3448 3449 3450 3451 3452 3453 3454 3455 3456 3457 3458 3459 3460 3461 3462 3463 3464 3465 3466 3467 3468 3469 3470 3471 3472 3473 3474 3475 3476 3477 3478 3479 3480 3481 3482 3483 3484 3485 3486 3487 3488 3489 3490 3491 3492 3493 3494 3495 3496 3497 3498 3499 3500 3501 3502 3503 3504 3505 3506 3507 3508 3509 3510 3511 3512 3513 3514 3515 3516 3517 3518 3519 3520 3521 3522 3523 3524 3525 3526 3527 3528 3529 3530 3531 3532 3533 3534 3535 3536 3537 3538 3539 3540 3541 3542 3543 3544 3545 3546 3547 3548 3549 3550 3551 3552 3553 3554 3555 3556 3557 3558 3559 3560 3561 3562 3563 3564 3565 3566 3567 3568 3569 3570 3571 3572 3573 3574 3575 3576 3577 3578 3579 3580 3581 3582 3583 3584 3585 3586 3587 3588 3589 3590 3591 3592 3593 3594 3595 3596 3597 3598 3599 3600 3601 3602 3603 3604 3605 3606 3607 3608 3609 3610 3611 3612 3613 3614 3615 3616 3617 3618 3619 3620 3621 3622 3623 3624 3625 3626 3627 3628 3629 3630 3631 3632 3633 3634 3635 3636 3637 3638 3639 3640 3641 3642 3643 3644 3645 3646 3647 3648 3649 3650 3651 3652 3653 3654 3655 3656 3657 3658 3659 3660 3661 3662 3663 3664 3665 3666 3667 3668 3669 3670 3671 3672 3673 3674 3675 3676 3677 3678 3679 3680 3681 3682 3683 3684 3685 3686 3687 3688 3689 3690 3691 3692 3693 3694 3695 3696 3697 3698 3699 3700 3701 3702 3703 3704 3705 3706 3707 3708 3709 3710 3711 3712 3713 3714 3715 3716 3717 3718 3719 3720 3721 3722 3723 3724 3725 3726 3727 3728 3729 3730 3731 3732 3733 3734 3735 3736 3737 3738 3739 3740 3741 3742 3743 3744 3745 3746 3747 3748 3749 3750 3751 3752 3753 3754 3755 3756 3757 3758 3759 3760 3761 3762 3763 3764 3765 3766 3767 3768 3769 3770 3771 3772 3773 3774 3775 3776 3777 3778 3779 3780 3781 3782 3783 3784 3785 3786 3787 3788 3789 3790 3791 3792 3793 3794 3795 3796 3797 3798 3799 3800 3801 3802 3803 3804 3805 3806 3807 3808 3809 3810 3811 3812 3813 3814 3815 3816 3817 3818 3819 3820 3821 3822 3823 3824 3825 3826 3827 3828 3829 3830 3831 3832 3833 3834 3835 3836 3837 3838 3839 3840 3841 3842 3843 3844 3845 3846 3847 3848 3849 3850 3851 3852 3853 3854 3855 3856 3857 3858 3859 3860 3861 3862 3863 3864 3865 3866 3867 3868 3869 3870 3871 3872 3873 3874 3875 3876 3877 3878 3879 3880 3881 3882 3883 3884 3885 3886 3887 3888 3889 3890 3891 3892 3893 3894 3895 3896 3897 3898 3899 3900 3901 3902 3903 3904 3905 3906 3907 3908 3909 3910 3911 3912 3913 3914 3915 3916 3917 3918 3919 3920 3921 3922 3923 3924 3925 3926 3927 3928 3929 3930 3931 3932 3933 3934 3935 3936 3937 3938 3939 3940 3941 3942 3943 3944 3945 3946 3947 3948 3949 3950 3951 3952 3953 3954 3955 3956 3957 3958 3959 3960 3961 3962 3963 3964 3965 3966 3967 3968 3969 3970 3971 3972 3973 3974 3975 3976 3977 3978 3979 3980 3981 3982 3983 3984 3985 3986 3987 3988 3989 3990 3991 3992 3993 3994 3995 3996 3997 3998 3999 4000 4001 4002 4003 4004 4005 4006 4007 4008 4009 4010 4011 4012 4013 4014 4015 4016 4017 4018 4019 4020 4021 4022 4023 4024 4025 4026 4027 4028 4029 4030 4031 4032 4033 4034 4035 4036 4037 4038 4039 4040 4041 4042 4043 4044 4045 4046 4047 4048 4049 4050 4051 4052 4053 4054 4055 4056 4057 4058 4059 4060 4061 4062 4063 4064 4065 4066 4067 4068 4069 4070 4071 4072 4073 4074 4075 4076 4077 4078 4079 4080 4081 4082 4083 4084 4085 4086 4087 4088 4089 4090 4091 4092 4093 4094 4095 4096 4097 4098 4099 4100 4101 4102 4103 4104 4105 4106 4107 4108 4109 4110 4111 4112 4113 4114 4115 4116 4117 4118 4119 4120 4121 4122 4123 4124 4125 4126 4127 4128 4129 4130 4131 4132 4133 4134 4135 4136 4137 4138 4139 4140 4141 4142 4143 4144 4145 4146 4147 4148 4149 4150 4151 4152 4153 4154 4155 4156 4157 4158 4159 4160 4161 4162 4163 4164 4165 4166 4167 4168 4169 4170 4171 4172 4173 4174 4175 4176 4177 4178 4179 4180 4181 4182 4183 4184 4185 4186 4187 4188 4189 4190 4191 4192 4193 4194 4195 4196 4197 4198 4199 4200 4201 4202 4203 4204 4205 4206 
<?xml version='1.0' encoding='UTF-8'?>
<!DOCTYPE html PUBLIC '-//W3C//DTD XHTML+RDFa 1.0//EN' 'http://www.w3.org/MarkUp/DTD/xhtml-rdfa-1.dtd'>
<html dir="ltr" about="" property="dcterms:language" content="en" xmlns="http://www.w3.org/1999/xhtml" xmlns:dcterms='http://purl.org/dc/terms/' xmlns:bibo='http://purl.org/ontology/bibo/' xmlns:foaf='http://xmlns.com/foaf/0.1/' xmlns:xsd='http://www.w3.org/2001/XMLSchema#'>
<head>
    <title>RDFa Core 1.1</title>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
    
<!--  
      === NOTA BENE ===      For the three scripts below, if your spec resides on dev.w3 you can check them      out in the same tree and use relative links so that they'll work offline,      -->

    <style type="text/css">
code           { font-family: monospace; }

span.hilite { color: red; /* font-weight: bold */ }

li p           { margin-top: 0.3em;
                 margin-bottom: 0.3em; }

div.explanation { background-color: #ADD8E6;
                   width: 80%;
                   margin: 12px; padding: 8px; }
div.explanation li { margin-top: 8px; }
div.explanation dd { margin: 4px; }

                   
.adef { 
    font-family: monospace; 
    font-weight: bold; 
    color: #ff4500 !important;
}

.aref { 
    font-family: monospace; 
    font-weight: bold; 
    color: #ff4500 !important;
}

span.entity { color: red; }

span.element { color: green; }
</style> 
    
<!--     <script src='/ReSpec.js/js/respec.js' class='remove'></script>  -->

    
  <style type="text/css">
/*****************************************************************
 * ReSpec CSS
 * Robin Berjon (robin at berjon dot com)
 * v0.05 - 2009-07-31
 *****************************************************************/


/* --- INLINES --- */
em.rfc2119 { 
    text-transform:     lowercase;
    font-variant:       small-caps;
    font-style:         normal;
    color:              #900;
}

h1 acronym, h2 acronym, h3 acronym, h4 acronym, h5 acronym, h6 acronym, a acronym,
h1 abbr, h2 abbr, h3 abbr, h4 abbr, h5 abbr, h6 abbr, a abbr {
    border: none;
}

dfn {
    font-weight:    bold;
}

a.internalDFN {
    color:  inherit;
    border-bottom:  medium solid #99c;
    text-decoration:    none;
}

a.externalDFN {
    color:  inherit;
    border-bottom:  medium dotted #ccc;
    text-decoration:    none;
}

a.bibref {
    text-decoration:    none;
}

code {
    color:  #ff4500;
}


/* --- WEB IDL --- */
pre.idl {
    border-top: 1px solid #90b8de;
    border-bottom: 1px solid #90b8de;
    padding:    1em;
    line-height:    120%;
}

pre.idl::before {
    content:    "WebIDL";
    display:    block;
    width:      150px;
    background: #90b8de;
    color:  #fff;
    font-family:    initial;
    padding:    3px;
    font-weight:    bold;
    margin: -1em 0 1em -1em;
}

.idlType {
    color:  #ff4500;
    font-weight:    bold;
    text-decoration:    none;
}

/*.idlModule*/
/*.idlModuleID*/
/*.idlInterface*/
.idlInterfaceID {
    font-weight:    bold;
    color:  #005a9c;
}

.idlSuperclass {
    font-style: italic;
    color:  #005a9c;
}

/*.idlAttribute*/
.idlAttrType, .idlFieldType {
    color:  #005a9c;
}
.idlAttrName, .idlFieldName {
    color:  #ff4500;
}
.idlAttrName a, .idlFieldName a {
    color:  #ff4500;
    border-bottom:  1px dotted #ff4500;
    text-decoration: none;
}

/*.idlMethod*/
.idlMethType {
    color:  #005a9c;
}
.idlMethName {
    color:  #ff4500;
}
.idlMethName a {
    color:  #ff4500;
    border-bottom:  1px dotted #ff4500;
    text-decoration: none;
}

/*.idlParam*/
.idlParamType {
    color:  #005a9c;
}
.idlParamName {
    font-style: italic;
}

.extAttr {
    color:  #666;
}

/*.idlConst*/
.idlConstType {
    color:  #005a9c;
}
.idlConstName {
    color:  #ff4500;
}
.idlConstName a {
    color:  #ff4500;
    border-bottom:  1px dotted #ff4500;
    text-decoration: none;
}

/*.idlException*/
.idlExceptionID {
    font-weight:    bold;
    color:  #c00;
}

.idlTypedefID, .idlTypedefType {
    color:  #005a9c;
}

.idlRaises, .idlRaises a.idlType, .idlRaises a.idlType code, .excName a, .excName a code {
    color:  #c00;
    font-weight:    normal;
}

.excName a {
    font-family:    monospace;
}

.idlRaises a.idlType, .excName a.idlType {
    border-bottom:  1px dotted #c00;
}

.excGetSetTrue, .excGetSetFalse, .prmNullTrue, .prmNullFalse, .prmOptTrue, .prmOptFalse {
    width:  45px;
    text-align: center;
}
.excGetSetTrue, .prmNullTrue, .prmOptTrue { color:  #0c0; }
.excGetSetFalse, .prmNullFalse, .prmOptFalse { color:  #c00; }

.idlImplements a {
    font-weight:    bold;
}

dl.attributes, dl.methods, dl.constants, dl.fields {
    margin-left:    2em;
}

.attributes dt, .methods dt, .constants dt, .fields dt {
    font-weight:    normal;
}

.attributes dt code, .methods dt code, .constants dt code, .fields dt code {
    font-weight:    bold;
    color:  #000;
    font-family:    monospace;
}

.attributes dt code, .fields dt code {
    background:  #ffffd2;
}

.attributes dt .idlAttrType code, .fields dt .idlFieldType code {
    color:  #005a9c;
    background:  transparent;
    font-family:    inherit;
    font-weight:    normal;
    font-style: italic;
}

.methods dt code {
    background:  #d9e6f8;
}

.constants dt code {
    background:  #ddffd2;
}

.attributes dd, .methods dd, .constants dd, .fields dd {
    margin-bottom:  1em;
}

table.parameters, table.exceptions {
    border-spacing: 0;
    border-collapse:    collapse;
    margin: 0.5em 0;
    width:  100%;
}
table.parameters { border-bottom:  1px solid #90b8de; }
table.exceptions { border-bottom:  1px solid #deb890; }

.parameters th, .exceptions th {
    color:  #fff;
    padding:    3px 5px;
    text-align: left;
    font-family:    initial;
    font-weight:    normal;
    text-shadow:    #666 1px 1px 0;
}
.parameters th { background: #90b8de; }
.exceptions th { background: #deb890; }

.parameters td, .exceptions td {
    padding:    3px 10px;
    border-top: 1px solid #ddd;
    vertical-align: top;
}

.parameters tr:first-child td, .exceptions tr:first-child td {
    border-top: none;
}

.parameters td.prmName, .exceptions td.excName, .exceptions td.excCodeName {
    width:  100px;
}

.parameters td.prmType {
    width:  120px;
}

table.exceptions table {
    border-spacing: 0;
    border-collapse:    collapse;
    width:  100%;
}

/* --- TOC --- */
.toc a {
    text-decoration:    none;
}

a .secno {
    color:  #000;
}

/* --- TABLE --- */
table.simple {
    border-spacing: 0;
    border-collapse:    collapse;
    border-bottom:  3px solid #005a9c;
}

.simple th {
    background: #005a9c;
    color:  #fff;
    padding:    3px 5px;
    text-align: left;
}

.simple th[scope="row"] {
    background: inherit;
    color:  inherit;
    border-top: 1px solid #ddd;
}

.simple td {
    padding:    3px 10px;
    border-top: 1px solid #ddd;
}

.simple tr:nth-child(even) {
    background: #f0f6ff;
}

/* --- DL --- */
.section dd > p:first-child {
    margin-top: 0;
}

.section dd > p:last-child {
    margin-bottom: 0;
}

.section dd {
    margin-bottom:  1em;
}

.section dl.attrs dd, .section dl.eldef dd {
    margin-bottom:  0;
}

/* --- EXAMPLES --- */
pre.example {
    border-top: 1px solid #ff4500;
    border-bottom: 1px solid #ff4500;
    padding:    1em;
    margin-top: 1em;
}

pre.example::before {
    content:    "Example";
    display:    block;
    width:      150px;
    background: #ff4500;
    color:  #fff;
    font-family:    initial;
    padding:    3px;
    font-weight:    bold;
    margin: -1em 0 1em -1em;
}

/* --- EDITORIAL NOTES --- */
.issue {
    padding:    1em;
    border: 1px solid #f00;
    background: #ffc;
}

.issue::before {
    content:    "Issue";
    display:    block;
    width:  150px;
    margin: -1.5em 0 0.5em 0;
    font-weight:    bold;
    border: 1px solid #f00;
    background: #fff;
    padding:    3px 1em;
}

.note {
    padding:    1em;
    border: 2px solid #cff6d9;
    background: #e2fff0;
}

.note::before {
    content:    "Note";
    display:    block;
    width:  150px;
    margin: -1.5em 0 0.5em 0;
    font-weight:    bold;
    border: 1px solid #cff6d9;
    background: #fff;
    padding:    3px 1em;
}

/* --- SYNTAX HIGHLIGHTING --- */
pre.sh_sourceCode {
  background-color: white;
  color: black;
  font-style: normal;
  font-weight: normal;
}

pre.sh_sourceCode .sh_keyword { color: #005a9c; font-weight: bold; }           /* language keywords */
pre.sh_sourceCode .sh_type { color: #666; }                            /* basic types */
pre.sh_sourceCode .sh_usertype { color: teal; }                             /* user defined types */
pre.sh_sourceCode .sh_string { color: red; font-family: monospace; }        /* strings and chars */
pre.sh_sourceCode .sh_regexp { color: orange; font-family: monospace; }     /* regular expressions */
pre.sh_sourceCode .sh_specialchar { color: 	#ffc0cb; font-family: monospace; }  /* e.g., \n, \t, \\ */
pre.sh_sourceCode .sh_comment { color: #A52A2A; font-style: italic; }         /* comments */
pre.sh_sourceCode .sh_number { color: purple; }                             /* literal numbers */
pre.sh_sourceCode .sh_preproc { color: #00008B; font-weight: bold; }       /* e.g., #include, import */
pre.sh_sourceCode .sh_symbol { color: blue; }                            /* e.g.+ */
pre.sh_sourceCode .sh_function { color: black; font-weight: bold; }         /* function calls and declarations */
pre.sh_sourceCode .sh_cbracket { color: red; }                              /* block brackets (e.g., {, }) */
pre.sh_sourceCode .sh_todo { font-weight: bold; background-color: #00FFFF; }   /* TODO and FIXME */

/* Predefined variables and functions (for instance glsl) */
pre.sh_sourceCode .sh_predef_var { color: #00008B; }
pre.sh_sourceCode .sh_predef_func { color: #00008B; font-weight: bold; }

/* for OOP */
pre.sh_sourceCode .sh_classname { color: teal; }

/* line numbers (not yet implemented) */
pre.sh_sourceCode .sh_linenum { display: none; }

/* Internet related */
pre.sh_sourceCode .sh_url { color: blue; text-decoration: underline; font-family: monospace; }

/* for ChangeLog and Log files */
pre.sh_sourceCode .sh_date { color: blue; font-weight: bold; }
pre.sh_sourceCode .sh_time, pre.sh_sourceCode .sh_file { color: #00008B; font-weight: bold; }
pre.sh_sourceCode .sh_ip, pre.sh_sourceCode .sh_name { color: #006400; }

/* for Prolog, Perl... */
pre.sh_sourceCode .sh_variable { color: #006400; }

/* for LaTeX */
pre.sh_sourceCode .sh_italics { color: #006400; font-style: italic; }
pre.sh_sourceCode .sh_bold { color: #006400; font-weight: bold; }
pre.sh_sourceCode .sh_underline { color: #006400; text-decoration: underline; }
pre.sh_sourceCode .sh_fixed { color: green; font-family: monospace; }
pre.sh_sourceCode .sh_argument { color: #006400; }
pre.sh_sourceCode .sh_optionalargument { color: purple; }
pre.sh_sourceCode .sh_math { color: orange; }
pre.sh_sourceCode .sh_bibtex { color: blue; }

/* for diffs */
pre.sh_sourceCode .sh_oldfile { color: orange; }
pre.sh_sourceCode .sh_newfile { color: #006400; }
pre.sh_sourceCode .sh_difflines { color: blue; }

/* for css */
pre.sh_sourceCode .sh_selector { color: purple; }
pre.sh_sourceCode .sh_property { color: blue; }
pre.sh_sourceCode .sh_value { color: #006400; font-style: italic; }

/* other */
pre.sh_sourceCode .sh_section { color: black; font-weight: bold; }
pre.sh_sourceCode .sh_paren { color: red; }
pre.sh_sourceCode .sh_attribute { color: #006400; }

</style><link href="http://www.w3.org/StyleSheets/TR/W3C-WD" rel="stylesheet" type="text/css" charset="utf-8" /></head>
  <body style="display: inherit; "><div class="head"><p><a href="http://www.w3.org/"><img width="72" height="48" src="http://www.w3.org/Icons/w3c_home" alt="W3C" /></a></p><h1 property="dcterms:title" class="title" id="title">RDFa Core 1.1</h1><h2 property="bibo:subtitle" id="subtitle">Syntax and processing rules for embedding RDF through attributes</h2><h2 property="dcterms:issued" datatype="xsd:dateTime" content="2011-12-15T06:00:00+0000" id="w3c-working-draft-15-december-2011"><acronym title="World Wide Web Consortium">W3C</acronym> Working Draft 15 December 2011</h2><dl><dt>This version:</dt><dd><a href="http://www.w3.org/TR/2011/WD-rdfa-core-20111215/">http://www.w3.org/TR/2011/WD-rdfa-core-20111215/</a></dd><dt>Latest published version:</dt><dd><a href="http://www.w3.org/TR/rdfa-core/">http://www.w3.org/TR/rdfa-core/</a></dd><dt>Latest editor's draft:</dt><dd><a href="http://www.w3.org/2010/02/rdfa/drafts#rdfa-core">http://www.w3.org/2010/02/rdfa/drafts#rdfa-core</a></dd><dt>Previous version:</dt><dd><a rel="dcterms:replaces" href="http://www.w3.org/TR/2011/WD-rdfa-core-20110331/">http://www.w3.org/TR/2011/WD-rdfa-core-20110331/</a></dd><dt>Latest recommendation:</dt><dd><a href="http://www.w3.org/TR/rdfa-syntax/">http://www.w3.org/TR/rdfa-syntax/</a></dd><dt>Editors:</dt><dd rel="bibo:editor"><span typeof="foaf:Person"><span property="foaf:name">Ben Adida</span>, Creative Commons <span class="ed_mailto"><a rel="foaf:mbox" href="mailto:ben@adida.net">ben@adida.net</a></span> </span>
</dd>
<dd rel="bibo:editor"><span typeof="foaf:Person"><span property="foaf:name">Mark Birbeck</span>, webBackplane <span class="ed_mailto"><a rel="foaf:mbox" href="mailto:mark.birbeck@webBackplane.com">mark.birbeck@webBackplane.com</a></span> </span>
</dd>
<dd rel="bibo:editor"><span typeof="foaf:Person"><a rel="foaf:homepage" property="foaf:name" content="Shane McCarron" href="http://blog.halindrome.com">Shane McCarron</a>, Applied Testing and Technology, Inc. <span class="ed_mailto"><a rel="foaf:mbox" href="mailto:shane@aptest.com">shane@aptest.com</a></span> </span>
</dd>
<dd rel="bibo:editor"><span typeof="foaf:Person"><a rel="foaf:homepage" property="foaf:name" content="Ivan Herman" href="http://www.w3.org/People/Ivan/">Ivan Herman</a>, <acronym title="World Wide Web Consortium">W3C</acronym> <span class="ed_mailto"><a rel="foaf:mbox" href="mailto:ivan@w3.org">ivan@w3.org</a></span> </span>
</dd>
</dl><p>This document is also available in these non-normative formats: <a href="rdfa-core-diff.html">Diff from previous Working Draft</a>, <a href="rdfa-core.ps">PostScript version</a>, and <a href="rdfa-core.pdf">PDF version</a>.</p><p class="copyright"><a rel="license" href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright">Copyright</a> © 2007-2011 <span rel="dcterms:publisher"><span typeof="foaf:Organization"><a rel="foaf:homepage" property="foaf:name" content="World Wide Web Consotrium" href="http://www.w3.org/"><acronym title="World Wide Web Consortium">W3C</acronym></a><sup>®</sup></span></span> (<a href="http://www.csail.mit.edu/"><acronym title="Massachusetts Institute of Technology">MIT</acronym></a>, <a href="http://www.ercim.eu/"><acronym title="European Research Consortium for Informatics and Mathematics">ERCIM</acronym></a>, <a href="http://www.keio.ac.jp/">Keio</a>), All Rights Reserved. <acronym title="World Wide Web Consortium">W3C</acronym> <a href="http://www.w3.org/Consortium/Legal/ipr-notice#Legal_Disclaimer">liability</a>, <a href="http://www.w3.org/Consortium/Legal/ipr-notice#W3C_Trademarks">trademark</a> and <a href="http://www.w3.org/Consortium/Legal/copyright-documents">document use</a> rules apply.</p><hr /></div>
    <div id="abstract" class="introductory section" property="dcterms:abstract" datatype="" typeof="bibo:Chapter" about="#abstract"><h2>Abstract</h2>
      <p>The current Web is primarily made up of an enormous number of documents
        that have been created using HTML. These documents contain significant
        amounts of structured data, which is largely unavailable to tools and
        applications. When publishers can express this data more completely, and
        when tools can read it, a new world of user functionality becomes
        available, letting users transfer structured data between applications
        and web sites, and allowing browsing applications to improve the user
        experience: an event on a web page can be directly imported into a
        user's desktop calendar; a license on a document can be detected so that
        users can be informed of their rights automatically; a photo's creator,
        camera setting information, resolution, location and topic can be
        published as easily as the original photo itself, enabling structured
        search and sharing.</p>
      <p>RDFa Core is a specification for attributes to express structured data
        in any markup language. The embedded data already available in the
        markup language (e.g., XHTML) can often be reused by the RDFa markup, so
        that publishers don't need to repeat significant data in the document
        content. The underlying abstract representation is RDF [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-PRIMER">RDF-PRIMER</a></cite>],
        which lets publishers build their own vocabulary, extend others, and
        evolve their vocabulary with maximal interoperability over time. The
        expressed structure is closely tied to the data, so that rendered data
        can be copied and pasted along with its relevant structure.</p>
      <p>The rules for interpreting the data are generic, so that there is no
        need for different rules for different formats; this allows authors and
        publishers of data to define their own formats without having to update
        software, register formats via a central authority, or worry that two
        formats may interfere with each other.</p>
      <p>RDFa shares some of the same goals with microformats [<cite><a class="bibref" rel="biblioentry" href="#bib-MICROFORMATS">MICROFORMATS</a></cite>].
        Whereas microformats specify both a syntax for embedding structured data
        into HTML documents and a vocabulary of specific terms for each
        microformat, RDFa specifies only a syntax and relies on independent
        specification of terms (often called vocabularies or taxonomies) by
        others. RDFa allows terms from multiple independently-developed
        vocabularies to be freely intermixed and is designed such that the
        language can be parsed without knowledge of the specific vocabulary
        being used. </p>
      <p>This document is a detailed syntax specification for RDFa, aimed at:</p>
      <ul>
        <li>those looking to create an RDFa Processor, and who therefore need a
          detailed description of the parsing rules;</li>
        <li>those looking to integrate RDFa into a new markup language;</li>
        <li>those looking to recommend the use of RDFa within their
          organization, and who would like to create some guidelines for their
          users;</li>
        <li>anyone familiar with RDF, and who wants to understand more about
          what is happening 'under the hood', when an RDFa Processor runs.</li>
      </ul>
      <p> For those looking for an introduction to the use of RDFa and some
        real-world examples, please consult the <a href="http://www.w3.org/TR/xhtml-rdfa-primer/">RDFa

          Primer</a>.</p>
      <div typeof="bibo:Chapter" about="#how-to-read-this-document" class="section">
        <h3 id="how-to-read-this-document">How to Read this Document</h3>
        <p>First, if you are not familiar with either RDFa <em>or</em> RDF, and
          simply want to add RDFa to your documents, then you may find the RDFa
          Primer [<cite><a class="bibref" rel="biblioentry" href="#bib-RDFA-PRIMER">RDFA-PRIMER</a></cite>] to be a better introduction.</p>
        <p>If you are already familiar with RDFa, and you want to examine the
          processing rules — perhaps to create an RDFa Processor — then you'll
          find the <a href="#s_model">Processing Model</a> section of most
          interest. It contains an overview of each of the processing steps,
          followed by more detailed sections, one for each rule.</p>
        <p>If you are not familiar with RDFa, but you <em>are</em> familiar
          with RDF, then you might find reading the <a href="#s_Syntax_overview">Syntax

            Overview</a> useful, before looking at the <a href="#s_model">Processing

            Model</a> since it gives a range of examples of markup that use
          RDFa. Seeing some examples first should make reading the processing
          rules easier.</p>
        <p>If you are not familiar with RDF, then you might want to take a look
          at the section on <a href="#s_rdfterminology">RDF Terminology</a>
          before trying to do too much with RDFa. Although RDFa is designed to
          be easy to author — and authors don't need to understand RDF to use it
          — anyone writing applications that <em>consume</em> RDFa will need to
          understand RDF. There is a lot of material about RDF on the web, and a
          growing range of tools that support RDFa, this document only contains
          enough background on RDF to make the goals of RDFa more clear.</p>
        <p class="note">RDFa is a way of expressing <em>RDF</em>-style
          relationships using simple attributes in existing markup languages
          such as HTML. RDF is fully internationalized, and permits the use of
          Internationalized Resource Identifiers, or IRIs. You will see the term
          'IRI' used throughout this specification. Even if you are not familiar
          with the term IRI, you probably have seen the term 'URI' or 'URL'.
          IRIs are an extension of URIs that permits the use of characters
          outside those of plain ASCII. RDF allows the use of these characters,
          and so does RDFa. This specification has been careful to use the
          correct term, IRI, to make it clear that this is the case.</p>
      </div>
    </div><div id="sotd" class="introductory section" typeof="bibo:Chapter" about="#sotd"><h2>Status of This Document</h2><p><em>This section describes the status of this document at the time of its publication. Other documents may supersede this document. A list of current <acronym title="World Wide Web Consortium">W3C</acronym> publications and the latest revision of this technical report can be found in the <a href="http://www.w3.org/TR/"><acronym title="World Wide Web Consortium">W3C</acronym> technical reports index</a> at http://www.w3.org/TR/.</em></p>
      
<!--  <p>This document has been reviewed by W3C Members, by software
developers, and by other W3C groups and interested parties, and isendorsed by the Director as a W3C Recommendation. It is a stabledocument and may be used as reference material or cited from anotherdocument. W3C's role in making the Recommendation is to draw attention
to the specification and to promote its widespread deployment. Thisenhances the functionality and interoperability of the Web.</p>  -->

      <p>This version reflects changes made as a result of comments received
        during a second Last Call period. That document was widely reviewed and
        the Working Group has made significant improvements and clarifications
        as a result. The Working Group believes that all comments received
        during the last call have been addressed.</p>
      <p>This is a revision of RDFa Syntax 1.0 [<cite><a class="bibref" rel="biblioentry" href="#bib-RDFA-SYNTAX">RDFA-SYNTAX</a></cite>]. Once development
        is complete, if accepted by the <acronym title="World Wide Web Consortium">W3C</acronym> membership, this document will
        supersede the <a href="http://www.w3.org/TR/2008/REC-rdfa-syntax-20081014">previous

          Recommendation</a>. There are a number of substantive differences
        between this version and its predecessor, including:</p>
      <ol>
        <li>The removal of the specific rules for XHTML - these are now defined
          in XHTML+RDFa [<cite><a class="bibref" rel="biblioentry" href="#bib-XHTML-RDFA">XHTML-RDFA</a></cite>]</li>
        <li>An expansion of the datatypes of some RDFa attributes so that they
          can contain Terms, CURIES, or Absolute IRIs.</li>
        <li>Host languages are permitted to define collections of default terms,
          default prefix mappings, and a default vocabulary.</li>
        <li>The ability to define a default vocabulary to use for Terms that are
          undefined.</li>
        <li>Terms are required to be compared in a case-insensitive manner.</li>
        <li>A richer behavior of the @property attribute, that can replace, in many cases the
        @rel attribute.</li>
        <li>A slightly different handling of @typeof, making it better adapted to practical usage.</li>
      </ol>
      <p>A <a href="http://rdfa.digitalbazaar.com/test-suite/">sample test
          harness</a> is available. This set of tests is not intended to be
        exhaustive. Users may find the tests to be useful examples of RDFa
        usage.
        
<!-- 
An <a href="http://www.w3.org/2006/07/SWD/RDFa/implementation-report/">implementation report</a> lists several implementationsof this specification tested during the Candidate Recommendationperiod.  A community-maintained <a href="http://rdfa.info/rdfa-implementations/">Wiki page</a> includes subsequent updates. -->

      </p>
    <p>This document was published by the <a href="http://www.w3.org/2010/02/rdfa">RDFa Working Group</a> as a Working Draft. This document is intended to become a <acronym title="World Wide Web Consortium">W3C</acronym> Recommendation. If you wish to make comments regarding this document, please send them to <a href="mailto:public-rdfa-wg@w3.org">public-rdfa-wg@w3.org</a> (<a href="mailto:public-rdfa-wg-request@w3.org?subject=subscribe">subscribe</a>, <a href="http://lists.w3.org/Archives/Public/public-rdfa-wg/">archives</a>). All feedback is welcome.</p><p>Publication as a Working Draft does not imply endorsement by the <acronym title="World Wide Web Consortium">W3C</acronym> Membership. This is a draft document and may be updated, replaced or obsoleted by other documents at any time. It is inappropriate to cite this document as other than work in progress.</p><p>This document was produced by a group operating under the <a href="http://www.w3.org/Consortium/Patent-Policy-20040205/">5 February 2004 <acronym title="World Wide Web Consortium">W3C</acronym> Patent Policy</a>. <acronym title="World Wide Web Consortium">W3C</acronym> maintains a <a href="http://www.w3.org/2004/01/pp-impl/44350/status" rel="disclosure">public list of any patent disclosures</a> made in connection with the deliverables of the group; that page also includes instructions for disclosing a patent. An individual who has actual knowledge of a patent which the individual believes contains <a href="http://www.w3.org/Consortium/Patent-Policy-20040205/#def-essential">Essential Claim(s)</a> must disclose the information in accordance with <a href="http://www.w3.org/Consortium/Patent-Policy-20040205/#sec-Disclosure">section 6 of the <acronym title="World Wide Web Consortium">W3C</acronym> Patent Policy</a>.</p></div><div id="toc" typeof="bibo:Chapter" about="#toc" class="section"><h2 class="introductory">Table of Contents</h2><ul class="toc"><li class="tocline"><a href="#s_motivation" class="tocxref"><span class="secno">1. </span>Motivation</a></li><li class="tocline"><a href="#s_Syntax_overview" class="tocxref"><span class="secno">2. </span>Syntax Overview</a><ul class="toc"><li class="tocline"><a href="#rdfa-attributes" class="tocxref"><span class="secno">2.1 </span>The RDFa Attributes</a></li><li class="tocline"><a href="#examples" class="tocxref"><span class="secno">2.2 </span>Examples</a></li></ul></li><li class="tocline"><a href="#s_rdfterminology" class="tocxref"><span class="secno">3. </span>RDF Terminology</a><ul class="toc"><li class="tocline"><a href="#statements" class="tocxref"><span class="secno">3.1 </span>Statements</a></li><li class="tocline"><a href="#triples" class="tocxref"><span class="secno">3.2 </span>Triples</a></li><li class="tocline"><a href="#T-IRI-reference" class="tocxref"><span class="secno">3.3 </span>IRI references</a></li><li class="tocline"><a href="#plain-literals" class="tocxref"><span class="secno">3.4 </span>Plain literals</a></li><li class="tocline"><a href="#typed-literals" class="tocxref"><span class="secno">3.5 </span>Typed literals</a></li><li class="tocline"><a href="#turtle" class="tocxref"><span class="secno">3.6 </span>Turtle</a></li><li class="tocline"><a href="#graphs" class="tocxref"><span class="secno">3.7 </span>Graphs</a></li><li class="tocline"><a href="#compact-uri-expressions" class="tocxref"><span class="secno">3.8 </span>Compact URI Expressions</a></li><li class="tocline"><a href="#markup-fragments-and-rdfa" class="tocxref"><span class="secno">3.9 </span>Markup Fragments and RDFa</a></li><li class="tocline"><a href="#a-description-of-rdfa-in-rdf-terms" class="tocxref"><span class="secno">3.10 </span>A description of RDFa in RDF terms</a></li></ul></li><li class="tocline"><a href="#conformance" class="tocxref"><span class="secno">4. </span>Conformance</a><ul class="toc"><li class="tocline"><a href="#processorconf" class="tocxref"><span class="secno">4.1 </span>RDFa Processor Conformance</a></li><li class="tocline"><a href="#hostlangconf" class="tocxref"><span class="secno">4.2 </span>RDFa Host Language Conformance</a></li><li class="tocline"><a href="#xmlrdfaconformance" class="tocxref"><span class="secno">4.3 </span>XML+RDFa Document Conformance</a></li></ul></li><li class="tocline"><a href="#s_syntax" class="tocxref"><span class="secno">5. </span>Attributes and Syntax</a><ul class="toc"><li class="tocline"><a href="#white_space" class="tocxref"><span class="secno">5.1 </span>White space within attribute values</a></li></ul></li><li class="tocline"><a href="#s_curies" class="tocxref"><span class="secno">6. </span>CURIE Syntax Definition</a><ul class="toc"><li class="tocline"><a href="#why-curies-and-not-qnames" class="tocxref"><span class="secno">6.1 </span>Why CURIEs and not QNames?</a></li></ul></li><li class="tocline"><a href="#s_model" class="tocxref"><span class="secno">7. </span>Processing Model</a><ul class="toc"><li class="tocline"><a href="#overview" class="tocxref"><span class="secno">7.1 </span>Overview</a></li><li class="tocline"><a href="#evaluation-context" class="tocxref"><span class="secno">7.2 </span>Evaluation Context</a></li><li class="tocline"><a href="#s_chaining" class="tocxref"><span class="secno">7.3 </span>Chaining</a></li><li class="tocline"><a href="#s_curieprocessing" class="tocxref"><span class="secno">7.4 </span>CURIE and IRI Processing</a><ul class="toc"><li class="tocline"><a href="#scoping-of-prefix-mappings" class="tocxref"><span class="secno">7.4.1 </span>Scoping of Prefix Mappings</a></li><li class="tocline"><a href="#general-use-of-curies-in-attributes" class="tocxref"><span class="secno">7.4.2 </span>General Use of CURIEs in Attributes</a></li><li class="tocline"><a href="#s_terms" class="tocxref"><span class="secno">7.4.3 </span>General Use of Terms in Attributes</a></li><li class="tocline"><a href="#use-of-curies-in-specific-attributes" class="tocxref"><span class="secno">7.4.4 </span>Use of CURIEs in Specific Attributes</a></li><li class="tocline"><a href="#s_blankNodes" class="tocxref"><span class="secno">7.4.5 </span>Referencing Blank Nodes</a></li></ul></li><li class="tocline"><a href="#s_sequence" class="tocxref"><span class="secno">7.5 </span>Sequence</a></li><li class="tocline"><a href="#processor-status" class="tocxref"><span class="secno">7.6 </span>Processor Status</a><ul class="toc"><li class="tocline"><a href="#accessing-the-processor-graph" class="tocxref"><span class="secno">7.6.1 </span>Accessing the Processor Graph</a></li><li class="tocline"><a href="#processor-graph-terms" class="tocxref"><span class="secno">7.6.2 </span>Processor Graph Terms</a></li></ul></li><li class="tocline"><a href="#vocabulary-expansion" class="tocxref"><span class="secno">7.7 </span>Vocabulary Expansion</a></li></ul></li><li class="tocline"><a href="#s_rdfaindetail" class="tocxref"><span class="secno">8. </span>RDFa Processing in detail</a><ul class="toc"><li class="tocline"><a href="#changing-the-evaluation-context" class="tocxref"><span class="secno">8.1 </span>Changing the evaluation context</a><ul class="toc"><li class="tocline"><a href="#setting-the-current-subject" class="tocxref"><span class="secno">8.1.1 </span>Setting the current subject</a><ul class="toc"><li class="tocline"><a href="#the-current-document" class="tocxref"><span class="secno">8.1.1.1 </span>The current document</a></li><li class="tocline"><a href="#using--about" class="tocxref"><span class="secno">8.1.1.2 </span>Using <span class="aref formerLink aref" title="about">@about</span></a></li><li class="tocline"><a href="#typing-resources-with--typeof" class="tocxref"><span class="secno">8.1.1.3 </span>Typing resources with <span class="aref formerLink aref" title="typeof">@typeof</span></a><ul class="toc"><li class="tocline"><a href="#chaining-with--property-and--typeof" class="tocxref"><span class="secno">8.1.1.3.1 </span>Chaining with <span class="aref formerLink aref" title="property">@property</span> and <span class="aref formerLink aref" title="typeof">@typeof</span></a></li></ul></li><li class="tocline"><a href="#determining-the-subject-with-neither--about-nor--typeof" class="tocxref"><span class="secno">8.1.1.4 </span>Determining the subject with neither <span class="aref formerLink aref" title="about">@about</span> nor <span class="aref formerLink aref" title="typeof">@typeof</span></a><ul class="toc"><li class="tocline"><a href="#inheriting-subject-from--resource" class="tocxref"><span class="secno">8.1.1.4.1 </span>Inheriting subject from <span class="aref formerLink aref" title="resource">@resource</span></a></li><li class="tocline"><a href="#inheriting-an-anonymous-subject" class="tocxref"><span class="secno">8.1.1.4.2 </span>Inheriting an anonymous subject</a></li></ul></li></ul></li></ul></li><li class="tocline"><a href="#s_Completing_Incomplete_Triples" class="tocxref"><span class="secno">8.2 </span>Completing incomplete triples'</a></li><li class="tocline"><a href="#object-resolution" class="tocxref"><span class="secno">8.3 </span>Object resolution</a><ul class="toc"><li class="tocline"><a href="#object-resolution-for-the--property-attribute" class="tocxref"><span class="secno">8.3.1 </span>Object resolution for the <span class="aref formerLink aref" title="property">@property</span> attribute</a><ul class="toc"><li class="tocline"><a href="#plain-literals-1" class="tocxref"><span class="secno">8.3.1.1 </span>Plain Literals</a><ul class="toc"><li class="tocline"><a href="#language-tags" class="tocxref"><span class="secno">8.3.1.1.1 </span>Language Tags</a></li></ul></li><li class="tocline"><a href="#typed-literals-1" class="tocxref"><span class="secno">8.3.1.2 </span>Typed literals</a></li><li class="tocline"><a href="#s-xml-literals" class="tocxref"><span class="secno">8.3.1.3 </span><span title="xml-literals">XML Literals</span></a></li></ul></li><li class="tocline"><a href="#iri-object-resolution" class="tocxref"><span class="secno">8.3.2 </span>IRI object resolution</a><ul class="toc"><li class="tocline"><a href="#using--resource-to-set-the-object" class="tocxref"><span class="secno">8.3.2.1 </span>Using <span class="aref formerLink aref" title="resource">@resource</span> to set the object</a></li><li class="tocline"><a href="#using--href-or--src" class="tocxref"><span class="secno">8.3.2.2 </span>Using <span class="aref formerLink aref" title="href">@href</span> or <span class="aref formerLink aref" title="src">@src</span></a></li><li class="tocline"><a href="#incomplete-triples" class="tocxref"><span class="secno">8.3.2.3 </span>Incomplete triples</a></li></ul></li></ul></li><li class="tocline"><a href="#list-generation" class="tocxref"><span class="secno">8.4 </span>List generation</a></li></ul></li><li class="tocline"><a href="#s_initialcontexts" class="tocxref"><span class="secno">9. </span>RDFa Initial Contexts</a></li><li class="tocline"><a href="#s_vocab_expansion" class="tocxref"><span class="secno">10. </span><span>RDFa Vocabulary Expansion</span></a><ul class="toc"><li class="tocline"><a href="#s_vocab_expansion_details" class="tocxref"><span class="secno">10.1 </span><span>Details of the RDFa Vocabulary
            Expansion</span></a><ul class="toc"><li class="tocline"><a href="#s_vocab_entailment" class="tocxref"><span class="secno">10.1.1 </span><span>RDFa Vocabulary Entailment</span></a></li></ul></li><li class="tocline"><a href="#s_expansion_control" class="tocxref"><span class="secno">10.2 </span>Vocabulary Expansion Control of RDFa Processors</a><ul class="toc"><li class="tocline"><a href="#s_vocab_guidelines" class="tocxref"><span class="secno">10.2.1 </span>Notes to RDFa Vocabulary Implementations and Publishing</a></li></ul></li></ul></li><li class="tocline"><a href="#s_datatypes" class="tocxref"><span class="secno">A. </span>CURIE Datatypes</a><ul class="toc"><li class="tocline"><a href="#xml-schema-definition" class="tocxref"><span class="secno">A.1 </span>XML Schema Definition</a></li><li class="tocline"><a href="#xml-dtd-definition" class="tocxref"><span class="secno">A.2 </span>XML DTD Definition</a></li></ul></li><li class="tocline"><a href="#vocabulary" class="tocxref"><span class="secno">B. </span>The RDFa Vocabulary</a><ul class="toc"><li class="tocline"><a href="#term-prefix-definitions-vocabulary" class="tocxref"><span class="secno">B.1 </span>Term and Prefix Assignments</a></li><li class="tocline"><a href="#processor-graph-reporting" class="tocxref"><span class="secno">B.2 </span>Processor Graph Reporting</a></li><li class="tocline"><a href="#vocabulary-relationship" class="tocxref"><span class="secno">B.3 </span>Term for vocabulary expansion</a></li><li class="tocline"><a href="#a_history" class="tocxref"><span class="secno">B.4 </span>Changes</a><ul class="toc"><li class="tocline"><a href="#major-differences-with-rdfa-syntax-1.0" class="tocxref"><span class="secno">B.4.1 </span>Major differences with RDFa Syntax 1.0</a></li></ul></li></ul></li><li class="tocline"><a href="#a_acks" class="tocxref"><span class="secno">C. </span>Acknowledgments</a></li><li class="tocline"><a href="#references" class="tocxref"><span class="secno">D. </span>References</a><ul class="toc"><li class="tocline"><a href="#normative-references" class="tocxref"><span class="secno">D.1 </span>Normative references</a></li><li class="tocline"><a href="#informative-references" class="tocxref"><span class="secno">D.2 </span>Informative references</a></li></ul></li></ul></div>
    
    <div class="informative section" id="s_motivation" typeof="bibo:Chapter" about="#s_motivation">
      
<!-- OddPage -->
<h2><span class="secno">1. </span>Motivation</h2><p><em>This section is non-normative.</em></p>
      <p>RDF/XML [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-SYNTAX">RDF-SYNTAX</a></cite>] provides sufficient flexibility to represent all
        of the abstract concepts in RDF [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-CONCEPTS">RDF-CONCEPTS</a></cite>]. However, it presents a
        number of challenges; first it is difficult or impossible to validate
        documents that contain RDF/XML using XML Schemas or DTDs, which
        therefore makes it difficult to import RDF/XML into other markup
        languages. Whilst newer schema languages such as RELAX NG
        [<cite><a class="bibref" rel="biblioentry" href="#bib-RELAXNG-SCHEMA">RELAXNG-SCHEMA</a></cite>] do provide a way to validate documents that contain
        arbitrary RDF/XML, it will be a while before they gain wide support.</p>
      <p>Second, even if one could add RDF/XML directly into an XML dialect like
        XHTML, there would be significant data duplication between the rendered
        data and the RDF/XML structured data. It would be far better to add RDF
        to a document without repeating the document's existing data. For
        example, an XHTML document that explicitly renders its author's name in
        the text—perhaps as a byline on a news site—should not need to repeat
        this name for the RDF expression of the same concept: it should be
        possible to supplement the existing markup in such a way that it can
        also be interpreted as RDF.</p>
      <p>Another reason for aligning the rendered data with the structured data
        is that it is highly beneficial to express the web data's structure 'in
        context'; as users often want to transfer structured data from one
        application to another, sometimes to or from a non-web-based
        application, the user experience can be enhanced. For example,
        information about specific rendered data could be presented to the user
        via 'right-clicks' on an item of interest.</p>
      <p>In the past, many attributes were 'hard-wired' directly into the markup
        language to represent specific concepts. For example, in XHTML 1.1
        [<cite><a class="bibref" rel="biblioentry" href="#bib-XHTML11">XHTML11</a></cite>] and HTML [<cite><a class="bibref" rel="biblioentry" href="#bib-HTML401">HTML401</a></cite>] there is <span class="aref">@cite</span>;
        the attribute allows an author to add information to a document which is
        used to indicate the origin of a quote.</p>
      <p>However, these 'hard-wired' attributes make it difficult to define a
        generic process for extracting metadata from any document since an RDFa
        Processor would need to know about each of the special attributes. One
        motivation for RDFa has been to devise a means by which documents can be
        augmented with metadata in a general, rather than hard-wired, manner.
        This has been achieved by creating a fixed set of attributes and parsing
        rules, but allowing those attributes to contain properties from any of a
        number of the growing range of available RDF vocabularies. In most cases
        the <em>values</em> of those properties are the information that is
        already in an author's document.</p>
      <p>RDFa alleviates the pressure on markup language designers to anticipate
        all the structural requirements users of their language might have, by
        outlining a new syntax for RDF that relies only on attributes. By
        adhering to the concepts and rules in this specification, language
        designers can import RDFa into their environment with a minimum of
        hassle and be confident that semantic data will be extractable from
        their documents by conforming processors. </p>
    </div>
    <div class="informative section" id="s_Syntax_overview" typeof="bibo:Chapter" about="#s_Syntax_overview">
      
<!-- OddPage -->
<h2><span class="secno">2. </span>Syntax Overview</h2><p><em>This section is non-normative.</em></p>
      <p>The following examples are intended to help readers who are not
        familiar with RDFa to quickly get a sense of how it works. For a more
        thorough introduction, please read the RDFa Primer [<cite><a class="bibref" rel="biblioentry" href="#bib-RDFA-PRIMER">RDFA-PRIMER</a></cite>].</p>
      <p>In RDF, it is common for people to shorten vocabulary terms via
        abbreviated IRIs that use a 'prefix' and a 'reference'. This mechanism
        is explained in detail in the section titled <a>Compact URI Expressions</a>.
        The examples throughout this document assume that the following
        vocabulary <a class="tref" title="prefix" href="#T-prefix">prefixes</a> have been defined:</p>
      <table>
        <tbody>
          <tr>
            <td rowspan="1" colspan="1">bibo:</td>
            <td rowspan="1" colspan="1">http://purl.org/ontology/bibo/</td>
          </tr>
          <tr>
            <td rowspan="1" colspan="1">cc:</td>
            <td rowspan="1" colspan="1">http://creativecommons.org/ns#</td>
          </tr>
          <tr>
            <td rowspan="1" colspan="1">dbp:</td>
            <td rowspan="1" colspan="1">http://dbpedia.org/property/</td>
          </tr>
          <tr>
            <td rowspan="1" colspan="1">dbp-owl:</td>
            <td rowspan="1" colspan="1">http://dbpedia.org/ontology/</td>
          </tr>
          <tr>
            <td rowspan="1" colspan="1">dbr:</td>
            <td rowspan="1" colspan="1">http://dbpedia.org/resource/</td>
          </tr>
          <tr>
            <td rowspan="1" colspan="1">dc:</td>
            <td rowspan="1" colspan="1">http://purl.org/dc/terms/</td>
          </tr>
          <tr>
            <td rowspan="1" colspan="1">ex:</td>
            <td rowspan="1" colspan="1">http://example.org/</td>
          </tr>
          <tr>
            <td rowspan="1" colspan="1">foaf:</td>
            <td rowspan="1" colspan="1">http://xmlns.com/foaf/0.1/</td>
          </tr>
          <tr>
            <td rowspan="1" colspan="1">rdf:</td>
            <td rowspan="1" colspan="1">
              http://www.w3.org/1999/02/22-rdf-syntax-ns#</td>
          </tr>
          <tr>
            <td rowspan="1" colspan="1">rdfa:</td>
            <td rowspan="1" colspan="1"> http://www.w3.org/ns/rdfa#</td>
          </tr>
          <tr>
            <td rowspan="1" colspan="1">rdfs:</td>
            <td rowspan="1" colspan="1"> http://www.w3.org/2000/01/rdf-schema#</td>
          </tr>
          
<!-- 
    <tr>      <td rowspan="1" colspan="1">taxo:</td>      <td rowspan="1" colspan="1">http://purl.org/rss/1.0/modules/taxonomy/</td>    </tr> -->

          <tr>
            <td rowspan="1" colspan="1">xhv:</td>
            <td rowspan="1" colspan="1">http://www.w3.org/1999/xhtml/vocab#</td>
          </tr>
          <tr>
            <td rowspan="1" colspan="1">xsd:</td>
            <td rowspan="1" colspan="1">http://www.w3.org/2001/XMLSchema#</td>
          </tr>
        </tbody>
      </table>
      <p class="note">In some of the examples below we have used IRIs with
        fragment identifiers that are local to the document containing the RDFa
        fragment identifiers shown (e.g., '<code>about=&quot;#me&quot;</code>'). This
        idiom, which is also used in RDF/XML [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-SYNTAX-GRAMMAR">RDF-SYNTAX-GRAMMAR</a></cite>] and other
        RDF serializations, gives a simple way to 'mint' new IRIs for entities
        described by RDFa and therefore contributes considerably to the
        expressive power of RDFa. Unfortunately, this practice is not at present
        covered by the media type registrations that govern the meaning of
        fragment identifiers (see section 3.5 of the URI specification
        [<cite><a class="bibref" rel="biblioentry" href="#bib-RFC3986">RFC3986</a></cite>], [<cite><a class="bibref" rel="biblioentry" href="#bib-RFC3023">RFC3023</a></cite>], and [<cite><a class="bibref" rel="biblioentry" href="#bib-RFC2854">RFC2854</a></cite>]). For more information about
        fragment identifier semantics, see [<cite><a class="bibref" rel="biblioentry" href="#bib-WEBARCH">WEBARCH</a></cite>] section 3.2.1.</p>
      <div id="rdfa-attributes" typeof="bibo:Chapter" about="#rdfa-attributes" class="section">
        <h3><span class="secno">2.1 </span>The RDFa Attributes</h3>
        <p>RDFa makes use of a number of commonly found attributes, as well as
          providing a few new ones. Attributes that already exist in widely
          deployed languages (e.g., HTML) have the same meaning they always did,
          although their syntax has been slightly modified in some cases. For
          example, in (X)HTML there is no clear way to add new <a class="aref" href="#A-rel" title="rel">@rel</a>
          values; RDFa sets out to explicitly solve this problem, and does so by
          allowing IRIs as values. It also introduces the concepts of <a class="tref" title="term" href="#T-term">terms</a>
          and '<a class="tref" title="curie" href="#T-curie">compact URI expressions</a>' — referred to
          as CURIEs in this document — which allow a full IRI value to be
          expressed succinctly. For a complete list of RDFa attribute names and
          syntax, see <a href="#s_syntax">Attributes and Syntax</a>.</p>
      </div>
      <div id="examples" typeof="bibo:Chapter" about="#examples" class="section">
        <h3><span class="secno">2.2 </span>Examples</h3>
        <p>In HTML, authors can include metadata and relationships concerning
          the current document by using the <code>meta</code> and <code>link</code>
          elements. For example, the author of the page along with the pages
          preceding and following the current page can be expressed using the
          link and meta elements:</p>
        <pre class="example">&lt;html xmlns=&quot;http://www.w3.org/1999/xhtml&quot;&gt;
  &lt;head&gt;
    &lt;title&gt;Page 7&lt;/title&gt;
    <span class="hilite">&lt;meta name=&quot;author&quot; content=&quot;Mark Birbeck&quot; /&gt;</span>
    <span class="hilite">&lt;link rel=&quot;prev&quot; href=&quot;page6.html&quot; /&gt;</span>
    <span class="hilite">&lt;link rel=&quot;next&quot; href=&quot;page8.html&quot; /&gt;</span>
  &lt;/head&gt;
  &lt;body&gt;...&lt;/body&gt;
&lt;/html&gt;</pre>
        <p>RDFa makes use of this concept, enhancing it with the ability to make
          use of other vocabularies by using full IRIs:</p>
        <pre class="example">&lt;html xmlns=&quot;http://www.w3.org/1999/xhtml&quot;&gt;
  &lt;head&gt;
    &lt;title&gt;My home-page&lt;/title&gt;
    &lt;meta property=&quot;<span class="hilite">http://purl.org/dc/terms/creator</span>&quot; content=&quot;Mark Birbeck&quot; /&gt;
    &lt;link rel=&quot;<span class="hilite">http://xmlns.com/foaf/0.1/topic</span>&quot; href=&quot;http://www.example.com/#us&quot; /&gt;
  &lt;/head&gt;
  &lt;body&gt;...&lt;/body&gt;
&lt;/html&gt;</pre>
        <p>Because using full IRIs like those above can be cumbersome, RDFa also
          permits the use of <a class="datatype internalDFN" title="CURIE" href="#dfn-curie">compact URI expressions</a>
          so an author can use a shorthand to reference terms in multiple
          vocabularies:</p>
        <pre class="example">&lt;html
  xmlns=&quot;http://www.w3.org/1999/xhtml&quot;
  <span class="hilite">prefix=&quot;foaf: http://xmlns.com/foaf/0.1/</span>
          <span class="hilite">dc: http://purl.org/dc/terms/&quot;</span>
  &gt;
  &lt;head&gt;
    &lt;title&gt;My home-page&lt;/title&gt;
    &lt;meta property=&quot;<span class="hilite">dc:creator</span>&quot; content=&quot;Mark Birbeck&quot; /&gt;
    &lt;link rel=&quot;<span class="hilite">foaf:topic</span>&quot; href=&quot;http://www.example.com/#us&quot; /&gt;
  &lt;/head&gt;
  &lt;body&gt;...&lt;/body&gt;
&lt;/html&gt;</pre>
        <p>RDFa supports the use of <a class="aref" href="#A-rel" title="rel">@rel</a> and <a class="aref" href="#A-rev" title="rev">@rev</a> on
          any element. This is even more useful with the addition of support for
          different vocabularies:</p>
        <pre id="ccLicense" class="example">This document is licensed under the 
&lt;a <span class="hilite">prefix=&quot;cc: http://creativecommons.org/ns#&quot;</span>
   <span class="hilite">rel=&quot;cc:license&quot;</span>
   href=&quot;http://creativecommons.org/licenses/by-nc-nd/3.0/&quot;&gt;
   Creative Commons By-NC-ND License
&lt;/a&gt;.</pre>
        <p>Not only can IRIs in the document be re-used to provide metadata, but
          so can inline text when used with <a class="aref" href="#A-property" title="property">@property</a>:</p>
        <pre class="example">&lt;html
  xmlns=&quot;http://www.w3.org/1999/xhtml&quot;
  <span class="hilite">prefix=&quot;cal: http://www.w3.org/2002/12/cal/ical#&quot;</span>
  &gt;
  &lt;head&gt;&lt;title&gt;Jo's Friends and Family Blog&lt;/title&gt;&lt;/head&gt;
  &lt;body&gt;
    &lt;p&gt;
      I'm holding
      &lt;span <span class="hilite">property=&quot;cal:summary&quot;</span>&gt;
        <span class="hilite">one last summer Barbecue</span>
      &lt;/span&gt;,
      on September 16th at 4pm.
    &lt;/p&gt;
  &lt;/body&gt;
&lt;/html&gt;</pre>
        <p>If some displayed text is different to the actual 'value' it
          represents, a more precise value can be added, which can optionally
          include <a class="aref" href="#A-datatype" title="datatype">@datatype</a>:</p>
        <pre class="example">&lt;html
  xmlns=&quot;http://www.w3.org/1999/xhtml&quot;
  prefix=&quot;cal: http://www.w3.org/2002/12/cal/ical#
  <span class="hilite">xsd: http://www.w3.org/2001/XMLSchema&quot;</span>
  &gt;
  &lt;head&gt;&lt;title&gt;Jo's Friends and Family Blog&lt;/title&gt;&lt;/head&gt;
  &lt;body&gt;
    &lt;p&gt;
      I'm holding
      &lt;span property=&quot;cal:summary&quot;&gt;
        one last summer Barbecue
      &lt;/span&gt;,
      on
      &lt;span <span class="hilite">property=&quot;cal:dtstart&quot;</span> <span class="hilite">content=&quot;2015-09-16T16:00:00-05:00&quot;</span>
            <span class="hilite">datatype=&quot;xsd:dateTime&quot;</span>&gt;
        September 16th at 4pm
      &lt;/span&gt;.
    &lt;/p&gt;
  &lt;/body&gt;
&lt;/html&gt;</pre>
        <p>In many cases a block of markup will contain a number of properties
          that relate to the same item; it's possible with RDFa to indicate the
          type of that item using <a class="aref" href="#A-typeof" title="typeof">@typeof</a>:</p>
        <pre class="example">&lt;html
  xmlns=&quot;http://www.w3.org/1999/xhtml&quot;
  prefix=&quot;cal: http://www.w3.org/2002/12/cal/ical#
          xsd: http://www.w3.org/2001/XMLSchema&quot;
  &gt;
  &lt;head&gt;&lt;title&gt;Jo's Friends and Family Blog&lt;/title&gt;&lt;/head&gt;
  &lt;body&gt;
    &lt;p <span class="hilite">typeof=&quot;cal:Vevent&quot;</span>&gt;
      I'm holding
      &lt;span property=&quot;cal:summary&quot;&gt;
        one last summer Barbecue
      &lt;/span&gt;,
      on
      &lt;span property=&quot;cal:dtstart&quot; content=&quot;2015-09-16T16:00:00-05:00&quot; 
            datatype=&quot;xsd:dateTime&quot;&gt;
        September 16th at 4pm
      &lt;/span&gt;.
    &lt;/p&gt;
  &lt;/body&gt;
&lt;/html&gt;</pre>
        <p>RDFa allows the document to contain metadata information about other
          documents and resources:</p>
        <pre class="example">&lt;html
  xmlns=&quot;http://www.w3.org/1999/xhtml&quot;
  prefix=&quot;bibo: http://purl.org/ontology/bibo/
          dc: http://purl.org/dc/terms/&quot;
  &gt;
  &lt;head&gt;
    &lt;title&gt;Books by Marco Pierre White&lt;/title&gt;
  &lt;/head&gt;
  &lt;body&gt;
    I think White's book
    '&lt;span <span class="hilite">about=&quot;urn:ISBN:0091808189&quot;</span> <span class="hilite">typeof=&quot;bibo:Book&quot;</span>
           <span class="hilite">property=&quot;dc:title&quot;</span>&gt;
      Canteen Cuisine
    &lt;/span&gt;'
    is well worth getting since although it's quite advanced stuff, he
    makes it pretty easy to follow. You might also like
    &lt;span <span class="hilite">about=&quot;urn:ISBN:1596913614&quot;</span> <span class="hilite">typeof=&quot;bibo:Book&quot;</span>
          <span class="hilite">property=&quot;dc:description&quot;</span>&gt;
      White's autobiography
    &lt;/span&gt;.
  &lt;/body&gt;
&lt;/html&gt;</pre>
        <p> When dealing with small amounts of markup, it is sometimes easier to
          use full IRIs, rather than CURIEs. The previous example can also be
          written as follows:</p>
        <pre class="example">&lt;html xmlns=&quot;http://www.w3.org/1999/xhtml&quot;&gt;
  &lt;head&gt;
    &lt;title&gt;Books by Marco Pierre White&lt;/title&gt;
  &lt;/head&gt;
  &lt;body&gt;
    I think White's book
    '&lt;span
     <span class="hilite">about=&quot;urn:ISBN:0091808189&quot;</span>
     <span class="hilite">typeof=&quot;http://purl.org/ontology/bibo/Book&quot;</span>
     <span class="hilite">property=&quot;http://purl.org/dc/terms/title&quot;</span>
     &gt;Canteen Cuisine&lt;/span&gt;'
    is well worth getting since although it's quite advanced stuff, he
    makes it pretty easy to follow. You might also like
    &lt;span
     <span class="hilite">about=&quot;urn:ISBN:1596913614&quot;</span>
     <span class="hilite">typeof=&quot;http://purl.org/ontology/bibo/Book&quot;</span>
     <span class="hilite">property=&quot;http://purl.org/dc/terms/description&quot;</span>
     &gt;White's autobiography&lt;/span&gt;.
  &lt;/body&gt;
&lt;/html&gt;</pre>
        <p>A simple way of defining a portion of a document using terms from a
          specific vocabulary is to use <a class="aref" href="#A-vocab" title="vocab">@vocab</a> to define a default
          vocabulary IRI. For example, to use FOAF terms:</p>
        <pre class="example">&lt;div <span class="hilite">vocab=&quot;http://xmlns.com/foaf/0.1/&quot;</span> about=&quot;#me&quot;&gt;
   My name is &lt;span <span class="hilite">property=&quot;name&quot;</span>&gt;John Doe&lt;/span&gt; and my blog is called
   &lt;a <span class="hilite">rel=&quot;homepage&quot;</span> href=&quot;http://example.org/blog/&quot;&gt;Understanding Semantics&lt;/a&gt;.
&lt;/div&gt;</pre>
        <p>The example above will produce the following triples, expressed here
          in <a href="#turtle">Turtle</a> syntax:</p>
        <pre class="example">@prefix foaf: &lt;http://xmlns.com/foaf/0.1/&gt; .
&lt;#me&gt; <span class="hilite">foaf:name</span> &quot;John Doe&quot; ;
      <span class="hilite">foaf:homepage</span> &lt;http://example.org/blog/&gt; .</pre>
        <p>In simple cases the <a class="aref" href="#A-property" title="property">@property</a> property can also be used
          in place of <a class="aref" href="#A-rel" title="rel">@rel</a>. Indeed, in case when the element does
          not contain <a class="aref" href="#A-rel" title="rel">@rel</a>, <a class="aref" href="#A-datatype" title="datatype">@datatype</a>, of <a class="aref" href="#A-content" title="content">@content</a>,
          but there is, for example, a <a class="aref" href="#A-href" title="href">@href</a>, the effect of <a class="aref" href="#A-property" title="property">@property</a>
          is analogous to the role of <a class="aref" href="#A-rel" title="rel">@rel</a>. For example, the
          previous example could have been written:</p>
        <pre class="example">&lt;div <span class="hilite">vocab=&quot;http://xmlns.com/foaf/0.1/&quot;</span> about=&quot;#me&quot;&gt;
   My name is &lt;span <span class="hilite">property=&quot;name&quot;</span>&gt;John Doe&lt;/span&gt; and my blog is called
   &lt;a <span class="hilite">property=&quot;homepage&quot;</span> href=&quot;http://example.org/blog/&quot;&gt;Understanding Semantics&lt;/a&gt;.
&lt;/div&gt;</pre> </div>
    </div>
    <div class="informative section" id="s_rdfterminology" typeof="bibo:Chapter" about="#s_rdfterminology">
      
<!-- OddPage -->
<h2><span class="secno">3. </span>RDF Terminology</h2><p><em>This section is non-normative.</em></p>
      <p> The previous section gave examples of typical markup in order to
        illustrate the structure of RDFa markup. RDFa is short for &quot;RDF in
        Attributes&quot;. In order to author RDFa you do not need to understand RDF,
        although it would certainly help. However, if you are building a system
        that consumes the RDF output of a language that supports RDFa you will
        almost certainly need to understand RDF. This section introduces the
        basic concepts and terminology of RDF. For a more thorough explanation
        of RDF, please refer to the RDF Concepts document [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-CONCEPTS">RDF-CONCEPTS</a></cite>] and
        the RDF Syntax Document [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-SYNTAX">RDF-SYNTAX</a></cite>]. </p>
      <div id="statements" typeof="bibo:Chapter" about="#statements" class="section">
        <h3><span class="secno">3.1 </span>Statements</h3>
        <p> The structured data that RDFa provides access to is a collection of
          <em>statements</em>. A statement is a basic unit of information that
          has been constructed in a specific format to make it easier to
          process. In turn, by breaking large sets of information down into a
          collection of statements, even very complex metadata can be processed
          using simple rules. </p>
        <p> To illustrate, suppose we have the following set of facts:</p>
        <pre class="example">Albert was born on March 14, 1879, in the German Empire. There is a picture of him at
the web address, http://en.wikipedia.org/wiki/Image:Albert_Einstein_Head.jpg.</pre>
        <p>This would be quite difficult for a machine to interpret, and it is
          certainly not in a format that could be passed from one data
          application to another. However, if we convert the information to a
          set of statements it begins to be more manageable. The same
          information could therefore be represented by the following shorter
          'statements':</p>
        <pre class="example">Albert was born on March 14, 1879.
Albert was born in the German Empire.
Albert has a picture at
  http://en.wikipedia.org/wiki/Image:Albert_Einstein_Head.jpg.</pre> </div>
      <div id="triples" typeof="bibo:Chapter" about="#triples" class="section">
        <h3><span class="secno">3.2 </span>Triples</h3>
        <p> To make this information machine-processable, RDF defines a
          structure for these statements. A statement is formally called a <dfn title="triple" id="T-triple"><em>triple</em></dfn>,
          meaning that it is made up of three components. The first is the <em>subject</em>
          of the triple, and is what we are making our statements <em>about</em>.
          In all of these examples the subject is 'Albert'. </p>
        <p> The second part of a triple is the property of the subject that we
          want to define. In the examples here, the properties would be 'was
          born on', 'was born in', and 'has a picture at'. These are more
          usually called <em>predicates</em> in RDF. </p>
        <p> The final part of a triple is called the <em>object</em>. In the
          examples here the three objects have the values 'March 14, 1879', 'the
          German Empire', and
          'http://en.wikipedia.org/wiki/Image:Albert_Einstein_Head.jpg'. </p>
        <p class="note">RDFa has complete support for internationalized
          characters. This includes internationalized characters in the subject,
          property and object location.</p>
      </div>
      <div id="T-IRI-reference" typeof="bibo:Chapter" about="#T-IRI-reference" class="section">
        <h3><span class="secno">3.3 </span>IRI references</h3>
        <p> Breaking complex information into manageable units helps us be
          specific about our data, but there is still some ambiguity. For
          example, which 'Albert' are we talking about? If another system has
          more facts about 'Albert', how could we know whether they are about
          the same person, and so add them to the list of things we know about
          that person? If we wanted to find people born in the German Empire,
          how could we know that the predicate 'was born in' has the same
          purpose as the predicate 'birthplace' that might exist in some other
          system? RDF solves this problem by replacing our vague terms with <dfn title="iri-reference" id="T-iri-reference">IRI

            references. </dfn></p>
        <p> IRIs are most commonly used to identify web pages, but RDF makes use
          of them as a way to provide unique identifiers for concepts. For
          example, we could identify the subject of all of our statements (the
          first part of each triple) by using the DBPedia [<a href="http://dbpedia.org">http://dbpedia.org</a>]
          IRI for Albert Einstein, instead of the ambiguous string 'Albert':</p>
        <pre class="example"><span class="hilite">&lt;http://dbpedia.org/resource/Albert_Einstein&gt;</span>
   has the name 
   Albert Einstein.
<span class="hilite">&lt;http://dbpedia.org/resource/Albert_Einstein&gt;</span>
   was born on 
   March 14, 1879.
<span class="hilite">&lt;http://dbpedia.org/resource/Albert_Einstein&gt;</span>
   was born in 
   the German Empire.
<span class="hilite">&lt;http://dbpedia.org/resource/Albert_Einstein&gt;</span>
   has a picture at
   http://en.wikipedia.org/wiki/Image:Albert_Einstein_Head.jpg.</pre>
        <p> IRI references are also used to uniquely identify the objects in
          metadata statements (the third part of each triple). The picture of
          Einstein is already an IRI, but we could also use an IRI to uniquely
          identify the country 'German Empire'. At the same time we'll indicate
          that the name and date of birth really are literals (and not IRIs), by
          putting quotes around them:</p>
        <pre class="example">&lt;http://dbpedia.org/resource/Albert_Einstein&gt; 
   has the name 
   <span class="hilite">&quot;</span>Albert Einstein<span class="hilite">&quot;</span>.
&lt;http://dbpedia.org/resource/Albert_Einstein&gt; 
   was born on 
   <span class="hilite">&quot;</span>March 14, 1879<span class="hilite">&quot;</span>.
&lt;http://dbpedia.org/resource/Albert_Einstein&gt; 
   was born in 
   <span class="hilite">&lt;http://dbpedia.org/resource/German_Empire&gt;</span>.
&lt;http://dbpedia.org/resource/Albert_Einstein&gt; 
   has a picture at
   <span class="hilite">&lt;</span>http://en.wikipedia.org/wiki/Image:Albert_Einstein_Head.jpg<span class="hilite">&gt;</span>.</pre>
        <p> IRI references are also used to ensure that predicates are
          unambiguous; now we can be sure that 'birthplace', 'place of birth',
          'Lieu de naissance' and so on, all mean the same thing:</p>
        <pre class="example">&lt;http://dbpedia.org/resource/Albert_Einstein&gt;
  <span class="hilite">&lt;http://xmlns.com/foaf/0.1/name&gt;</span>
  &quot;Albert Einstein&quot;.
&lt;http://dbpedia.org/resource/Albert_Einstein&gt;
  <span class="hilite">&lt;http://dbpedia.org/property/dateOfBirth&gt;</span>
  &quot;March 14, 1879&quot;.
&lt;http://dbpedia.org/resource/Albert_Einstein&gt;
  <span class="hilite">&lt;http://dbpedia.org/property/birthPlace&gt;</span>
  &lt;http://dbpedia.org/resource/German_Empire&gt;.
&lt;http://dbpedia.org/resource/Albert_Einstein&gt;
  <span class="hilite">&lt;http://xmlns.com/foaf/0.1/depiction&gt;</span>
  &lt;http://en.wikipedia.org/wiki/Image:Albert_Einstein_Head.jpg&gt;.</pre> </div>
      <div id="plain-literals" typeof="bibo:Chapter" about="#plain-literals" class="section">
        <h3><span class="secno">3.4 </span>Plain literals</h3>
        <p> Although IRI resources are always used for subjects and predicates,
          the object part of a triple can be either an IRI or a <dfn title="literal" id="T-literal"><em>literal</em></dfn>.
          In the example triples, Einstein's name is represented by a <dfn title="plain-literal" id="T-plain-literal"><em>plain

              literal</em></dfn>, which means that it is a basic string with no
          type or language information:</p>
        <pre class="example">&lt;http://dbpedia.org/resource/Albert_Einstein&gt;
  &lt;http://xmlns.com/foaf/0.1/name&gt; <span class="hilite">&quot;Albert Einstein&quot;</span>.</pre> </div>
      <div id="typed-literals" typeof="bibo:Chapter" about="#typed-literals" class="section">
        <h3><span class="secno">3.5 </span>Typed literals</h3>
        <p> Some literals, such as dates and numbers, have very specific
          meanings, so RDF provides a mechanism for indicating the type of a
          literal. A <dfn title="typed-literal" id="T-typed-literal"><em>typed literal</em></dfn>
          is indicated by attaching an IRI to the end of a <a class="tref" title="plain-literal" href="#T-plain-literal">plain literal</a>,
          and this IRI indicates the literal's datatype. This IRI is usually
          based on datatypes defined in the XML Schema Datatypes specification
          [<cite><a class="bibref" rel="biblioentry" href="#bib-XMLSCHEMA-2">XMLSCHEMA-2</a></cite>]. The following syntax would be used to unambiguously
          express Einstein's date of birth as a literal of type <code>http://www.w3.org/2001/XMLSchema#date</code>:</p>
        <pre class="example">&lt;http://dbpedia.org/resource/Albert_Einstein&gt;
  &lt;http://dbpedia.org/property/dateOfBirth&gt; 
     &quot;1879-03-14&quot;<span class="hilite">^^&lt;http://www.w3.org/2001/XMLSchema#date&gt;</span>.</pre> </div>
      <div id="turtle" typeof="bibo:Chapter" about="#turtle" class="section">
        <h3><span class="secno">3.6 </span>Turtle</h3>
        <p> RDF itself does not have one set way to express triples, since the
          key ideas of RDF are the triple and the use of IRIs, and <em>not</em>
          any particular syntax. However, there are a number of mechanisms for
          expressing triples, such as RDF/XML [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-SYNTAX-GRAMMAR">RDF-SYNTAX-GRAMMAR</a></cite>], Turtle
          [<cite><a class="bibref" rel="biblioentry" href="#bib-TURTLE">TURTLE</a></cite>], and of course RDFa. Many discussions of RDF make use of
          the <em>Turtle</em> syntax to explain their ideas, since it is quite
          compact. The examples we have just seen are already using this syntax,
          and we'll continue to use it throughout this document when we need to
          talk about the RDF that could be generated from some RDFa. Turtle
          allows long IRIs to be abbreviated by using an IRI mapping, which can
          be used to express a compact IRI expression as follows:</p>
        <pre class="example"><span class="hilite">@prefix dbp: &lt;http://dbpedia.org/property/&gt; .</span>
<span class="hilite">@prefix foaf: &lt;http://xmlns.com/foaf/0.1/&gt; .</span>
&lt;http://dbpedia.org/resource/Albert_Einstein&gt;
  <span class="hilite">foaf:name</span> &quot;Albert Einstein&quot; .
&lt;http://dbpedia.org/resource/Albert_Einstein&gt;
  <span class="hilite">dbp:birthPlace</span> &lt;http://dbpedia.org/resource/German_Empire&gt; .</pre>
        <p>Here 'dbp:' has been mapped to the IRI for DBPedia and 'foaf:' has
          been mapped to the IRI for the 'Friend of a Friend' taxonomy.</p>
        <p>Any IRI in Turtle could be abbreviated in this way. This means that
          we could also have used the same technique to abbreviate the
          identifier for Einstein, as well as the datatype indicator:</p>
        <pre class="example">@prefix dbp: &lt;http://dbpedia.org/property/&gt; .
<span class="hilite">@prefix dbr: &lt;http://dbpedia.org/resource/&gt; .</span>
@prefix foaf: &lt;http://xmlns.com/foaf/0.1/&gt; .
<span class="hilite">@prefix xsd: &lt;http://www.w3.org/2001/XMLSchema#&gt; .</span>
<span class="hilite">dbr:Albert_Einstein</span> dbp:dateOfBirth &quot;1879-03-14&quot;^^<span class="hilite">xsd:date</span> .
<span class="hilite">dbr:Albert_Einstein</span>
  foaf:depiction &lt;http://en.wikipedia.org/wiki/Image:Albert_Einstein_Head.jpg&gt; .</pre>
        <p> When writing examples, you will often see the following IRI in the
          Turtle representation:</p>
        <pre class="example">&lt;&gt;</pre>
        <p> This indicates the 'current document', i.e., the document being
          processed. In reality there would always be a full IRI based on the
          document's location, but this abbreviation serves to make examples
          more compact. Note in particular that the whole technique of
          abbreviation is merely a way to make examples more compact, and the
          actual triples generated would always use the full IRIs.</p>
      </div>
      <div id="graphs" typeof="bibo:Chapter" about="#graphs" class="section">
        <h3><span class="secno">3.7 </span>Graphs</h3>
        <p> A collection of triples is called a <em>graph</em>. All of the
          triples that are defined by this specification are contained in the <a class="tref" title="output-graph" href="#T-output-graph">output

            graph</a> by an RDFa Processor. For more information on graphs
          and other RDF concepts, see [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-CONCEPTS">RDF-CONCEPTS</a></cite>]. </p>
      </div>
      <div id="compact-uri-expressions" typeof="bibo:Chapter" about="#compact-uri-expressions" class="section">
        <h3><span class="secno">3.8 </span>Compact URI Expressions</h3>
        <p>In order to allow for the compact expression of RDF statements, RDFa
          allows the contraction of most <a class="tref" title="iri-reference" href="#T-iri-reference">IRI reference</a>s into a
          form called a 'compact URI expression', or <a class="datatype internalDFN" title="CURIE" href="#dfn-curie">CURIE</a>. A
          detailed discussion of this mechanism is in the section <a href="#s_curieprocessing">CURIE

            and IRI Processing</a>.</p>
        <p>Note that CURIEs are only used in the markup and Turtle examples, and
          will never appear in the generated <a class="tref" title="triple" href="#T-triple">triple</a>s, which are
          defined by RDF to use <a class="tref" title="iri-reference" href="#T-iri-reference">IRI reference</a>s.</p>
        <p>Full details on how CURIEs are processed are in the section titled <a href="#s_curieprocessing">CURIE

            Processing</a>.</p>
      </div>
      <div id="markup-fragments-and-rdfa" typeof="bibo:Chapter" about="#markup-fragments-and-rdfa" class="section">
        <h3><span class="secno">3.9 </span>Markup Fragments and RDFa</h3>
        <p>A growing use of embedded metadata is to take fragments of markup and
          move them from one document to another. This may happen through the
          use of tools, such as drag-and-drop in a browser, or through snippets
          of code provided to authors for inclusion in their documents. (A good
          example of the latter is the <a href="#ccLicense">licensing fragment
            provided by Creative Commons</a>.)</p>
        <p>However, those involved in creating fragments (either by building
          tools, or authoring snippets), should be aware that this specification
          does not say how fragments are processed. Specifically, the processing
          of a fragment 'outside' of a complete document is undefined because
          RDFa processing is largely about context. Future versions of this or
          related specifications may do more to define this behavior.</p>
        <p>Developers of tools that process fragments, or authors of fragments
          for manual inclusion, should also bear in mind what will happen to
          their fragment once it is included in a complete document. They should
          carefully consider the amount of 'context' information that will be
          needed in order to ensure a correct interpretation of their fragment.</p>
      </div>
      <div id="a-description-of-rdfa-in-rdf-terms" typeof="bibo:Chapter" about="#a-description-of-rdfa-in-rdf-terms" class="section">
        <h3><span class="secno">3.10 </span>A description of RDFa in RDF terms</h3>
        <p> The following is a brief description of RDFa in terms of the RDF
          terminology introduced here. It may be useful to readers with an RDF
          background: </p>
        <p>The aim of RDFa is to allow a single <a class="tref" title="rdf-graph" href="#T-rdf-graph">RDF graph</a> to be
          carried in various types of document markup. An <dfn title="rdf-graph" id="T-rdf-graph">RDF graph</dfn>
          comprises <dfn title="node" id="T-node">node</dfn>s linked by relationships. The basic unit
          of an <a class="tref" title="rdf-graph" href="#T-rdf-graph">RDF graph</a> is a <a class="tref" title="triple" href="#T-triple">triple</a>, in which a
          subject <a class="tref" title="node" href="#T-node">node</a> is linked to an object <a class="tref" title="node" href="#T-node">node</a>
          via a <a class="tref" title="predicate" href="#T-predicate">predicate</a>. The <dfn title="subject" id="T-subject">subject</dfn> <a class="tref" title="node" href="#T-node">node</a>
          is always either a <a class="tref" title="iri-reference" href="#T-iri-reference">IRI reference</a> or a <dfn title="bnode" id="T-bnode">blank
            node (or bnode)</dfn>, the <dfn title="predicate" id="T-predicate">predicate</dfn> is <em>always</em>
          a <a class="tref" title="iri-reference" href="#T-iri-reference">IRI reference</a>, and the object of a statement can be a
          <a class="tref" title="iri-reference" href="#T-iri-reference">IRI reference</a>, a <a class="tref" title="literal" href="#T-literal">literal</a>, or a <a class="tref" title="bnode" href="#T-bnode">bnode</a>.</p>
        <p>In RDFa, a subject <a class="tref" title="iri-reference" href="#T-iri-reference">IRI reference</a> is generally indicated
          using <a class="aref" href="#A-about" title="about">@about</a> and predicates are represented using one of
          <a class="aref" href="#A-property" title="property">@property</a>, <a class="aref" href="#A-rel" title="rel">@rel</a>, or <a class="aref" href="#A-rev" title="rev">@rev</a>.
          Objects which are <a class="tref" title="iri-reference" href="#T-iri-reference">IRI reference</a>s are represented using <a class="aref" href="#A-resource" title="resource">@resource</a>,
          <a class="aref" href="#A-src" title="src">@src</a>, or <a class="aref" href="#A-href" title="href">@href</a>, whilst objects that are <a class="tref" title="literal" href="#T-literal">literal</a>s
          are represented either with <a class="aref" href="#A-content" title="content">@content</a> or the content of
          the element in question (with an optional datatype expressed using <a class="aref" href="#A-datatype" title="datatype">@datatype</a>,
          and an optional language expressed using a Host Language-defined
          mechanism such as <span class="aref">xml:lang</span>).</p>
      </div>
    </div>
    <div id="conformance" class="normative section" typeof="bibo:Chapter" about="#conformance">
<!-- OddPage -->
<h2><span class="secno">4. </span>Conformance</h2><p>As well as sections marked as non-normative, all authoring guidelines, diagrams, examples, and notes in this specification are non-normative. Everything else in this specification is normative.</p>
<p>The key words <em class="rfc2119" title="must">must</em>, <em class="rfc2119" title="must not">must not</em>, <em class="rfc2119" title="required">required</em>, <em class="rfc2119" title="should">should</em>, <em class="rfc2119" title="should not">should not</em>, <em class="rfc2119" title="recommended">recommended</em>, <em class="rfc2119" title="may">may</em>, and <em class="rfc2119" title="optional">optional</em> in this specification are to be interpreted as described in [<cite><a class="bibref" rel="biblioentry" href="#bib-RFC2119">RFC2119</a></cite>].</p>

      <div id="processorconf" typeof="bibo:Chapter" about="#processorconf" class="section">
        <h3><span class="secno">4.1 </span>RDFa Processor Conformance</h3>
        <p>A conforming RDFa Processor <em class="rfc2119" title="must">must</em> make available to a consuming
          application a single <a class="tref" title="rdf-graph" href="#T-rdf-graph">RDF graph</a> containing all possible
          triples generated by using the rules in the <a href="#s_model">Processing
            Model</a> section. This specification uses the term <dfn title="output-graph" id="T-output-graph">output
            graph</dfn> to mean all of the triples asserted by a document
          according to the <a href="#s_model">Processing Model</a> section. The
          term <dfn title="processor-graph" id="T-processor-graph">processor graph</dfn> is used to denote the collection of
          all informational, warning, and error triples that may be generated by
          the RDFa Processor to <a href="#processor-status">report its status</a>.
          The <a class="tref" title="output-graph" href="#T-output-graph">output graph</a> and the <a class="tref" title="processor-graph" href="#T-processor-graph">processor graph</a>
          are separate graphs and <em class="rfc2119" title="must not">must not</em> be stored in the same graph by the
          RDFa Processor. </p>
        <p>A conforming RDFa Processor <em class="rfc2119" title="may">may</em> make available additional triples
          that have been generated using rules not described here, but these
          triples <em class="rfc2119" title="must not">must not</em> be made available in the <a class="tref" title="output-graph" href="#T-output-graph">output graph</a>.
          (Whether these additional triples are made available in one or more
          additional <a class="tref" title="rdf-graph" href="#T-rdf-graph">RDF graph</a>s is implementation-specific, and
          therefore not defined here.)</p>
        <p>A conforming RDFa Processor <em class="rfc2119" title="must">must</em> preserve white space in both <a class="tref" title="plain-literal" href="#T-plain-literal">plain

            literal</a>s and <a class="tref" title="xml-literals" href="#T-xml-literals">XML literals</a>.
          However, it may be the case that the architecture in which a processor
          operates has made changes to the white space in a document before that
          document ever reaches the RDFa Processor (e.g., [<cite><a class="bibref" rel="biblioentry" href="#bib-XMLSCHEMA-1">XMLSCHEMA-1</a></cite>]
          processors are permitted to 'normalize' white space in attribute
          values - see section 3.1.4). To ensure maximum consistency between
          processing environments, authors <em class="rfc2119" title="should">should</em> remove any unnecessary white
          space in their plain and XML Literal content.</p>
        <p>A conforming RDFa Processor <em class="rfc2119" title="must">must</em> examine the media type of a document
          it is processing to determine the document's Host Language. If the
          RDFa Processor is unable to determine the media type, or does not
          support the media type, the RDFa Processor <em class="rfc2119" title="must">must</em> process the document
          as if it were media type <code>application/xml</code>. See <a href="#xmlrdfaconformance">XML+RDFa

            Document Conformance</a>. A Host Language <em class="rfc2119" title="may">may</em> specify additional
          announcement mechanisms.</p>
        <p class="note">A conforming RDFa Processor <em class="rfc2119" title="may">may</em> use additional
          mechanisms (e.g., the DOCTYPE, a file extension, the root element) to
          attempt to determine the Host Language if the media type is
          unavailable. These mechanisms are unspecified.</p>
      </div>
      <div id="hostlangconf" typeof="bibo:Chapter" about="#hostlangconf" class="section">
        <h3><span class="secno">4.2 </span>RDFa Host Language Conformance</h3>
        <p>Host Languages that incorporate RDFa must adhere to the following:</p>
        <ul>
          <li> All of the facilities required in this specification <em class="rfc2119" title="must">must</em> be
            included in the Host Language.</li>
          <li>The attributes defined in this specification <em class="rfc2119" title="must">must</em> be included in
            the content model of the Host Language.</li>
          <li> If the Host Language uses XML Namespaces [<cite><a class="bibref" rel="biblioentry" href="#bib-XML-NAMES">XML-NAMES</a></cite>], the
            attributes in this specification <em class="rfc2119" title="should">should</em> be defined in 'no
            namespace'. (e.g., when the attributes are used on elements in the
            Host Language's namespace, they can be used with no qualifying
            prefix: <code>&lt;myml:myElement property=&quot;next&quot;&gt;</code>).

            When a Host Language does not use the attributes in 'no namespace',
            they <em class="rfc2119" title="must">must</em> be referenced via the XHTML Namespace (<code>http://www.w3.org/1999/xhtml</code>).</li>
          <li>If the Host Language has its own definition for any attribute
            defined in this specification, that definition <em class="rfc2119" title="must">must</em> be such that the
            processing required by this specification remains possible when the
            attribute is used in a way consistent with the requirements herein.</li>
          <li>The Host Language <em class="rfc2119" title="may">may</em> specify an <a class="tref" title="initial-context" href="#T-initial-context">initial context</a>
            (e.g., the definition of terms, IRI mappings, and/or a default
            vocabulary IRI). Such an <a class="tref" title="initial-context" href="#T-initial-context">initial context</a> <em class="rfc2119" title="should">should</em> be
            defined using the conventions defined in <a href="#s_initialcontexts">RDFa

              Initial Contexts</a>.</li>
        </ul>
      </div>
      <div id="xmlrdfaconformance" typeof="bibo:Chapter" about="#xmlrdfaconformance" class="section">
        <h3><span class="secno">4.3 </span>XML+RDFa Document Conformance</h3>
        <p>This specification does not define a stand-alone document type. The
          attributes herein are intended to be integrated into other host
          languages (e.g., HTML+RDFa or XHTML+RDFa). However, this specification
          <strong>does</strong> define processing rules for generic XML
          documents - that is, those documents delivered as media types <code>text/xml</code>
          or <code>application/xml</code>. Such documents must meet all of the
          following criteria:</p>
        <ol>
          <li>The document <em class="rfc2119" title="must">must</em> be well-formed as defined in [<cite><a class="bibref" rel="biblioentry" href="#bib-XML10-4e">XML10-4e</a></cite>]. </li>
          <li> The document <em class="rfc2119" title="must">must</em> use the attributes defined in this
            specification through references to the XHTML namespace (<code>http://www.w3.org/1999/xhtml</code>).

          </li>
        </ol>
        <p>When an RDFa Processor processes an XML+RDFa document, it does so via
          the following <a class="tref" title="initial-context" href="#T-initial-context">initial context</a>:</p>
        <ol>
          <li>There are default terms (e.g., <code>describedby</code>, <code>license</code>, and <code>role</code>), defined
            in <a href="http://www.w3.org/2011/rdfa-context/rdfa-1.1"><code>http://www.w3.org/2011/rdfa-context/rdfa-1.1</code></a>.</li>
          <li>There are default prefix mappings (e.g., <code>dc</code>),
            defined in <a href="http://www.w3.org/2011/rdfa-context/rdfa-1.1"><code>http://www.w3.org/2011/rdfa-context/rdfa-1.1</code></a>.</li>
          <li>There is no default vocabulary IRI.</li>
          <li>The <a class="tref" title="base" href="#T-base">base</a> can be set using the <span class="aref">@xml:base</span>
            attribute as defined in [<cite><a class="bibref" rel="biblioentry" href="#bib-XML10-4e">XML10-4e</a></cite>].</li>
          <li>The <a class="tref" title="current-language" href="#T-current-language">current language</a> can be set using <span class="aref">@xml:lang</span>
            attribute. </li>
        </ol>
      </div>
    </div>
    <div class="normative section" id="s_syntax" typeof="bibo:Chapter" about="#s_syntax">
      
<!-- OddPage -->
<h2><span class="secno">5. </span>Attributes and Syntax</h2>
      <p>This specification defines a number of attributes and the way in which
        the values of those attributes are to be interpreted when generating RDF
        triples. This section defines the attributes and the syntax of their
        values.</p>
      <dl>
        <dt><dfn class="adef" title="about" id="A-about">about</dfn></dt>
        <dd>a <a class="datatype internalDFN" title="SafeCURIEorCURIEorIRI" href="#dfn-safecurieorcurieoriri">SafeCURIEorCURIEorIRI</a>, used for stating what the
          data is about (a 'subject' in RDF terminology);</dd>
        <dt><dfn class="adef" title="content" id="A-content">content</dfn> </dt>
        <dd>a <code>CDATA</code> string, for supplying machine-readable content
          for a literal (a 'plain literal object', in RDF terminology);</dd>
        <dt><dfn class="adef" title="datatype" id="A-datatype">datatype</dfn></dt>
        <dd>a <a class="datatype internalDFN" title="TERMorCURIEorAbsIRI" href="#dfn-termorcurieorabsiri">TERMorCURIEorAbsIRI</a> representing a datatype, to
          express the datatype of a literal;</dd>
        <dt><dfn class="adef" title="href" id="A-href">href</dfn></dt>
        <dd>a traditionally navigable <a class="externalDFN" title="URI">URI</a> for expressing the
          partner resource of a relationship (a 'resource object', in RDF
          terminology);</dd>
        <dt><dfn class="adef" title="prefix" id="A-prefix">prefix</dfn></dt>
        <dd>a white space separated list of prefix-name IRI pairs of the form
          <pre><a href="#P_prefix">NCName</a> ':' ' '+ xs:anyURI</pre>
        </dd>
        <dt><dfn class="adef" title="property" id="A-property">property</dfn></dt>
        <dd>a white space separated list of <a class="datatype internalDFN" title="TERMorCURIEorAbsIRIs" href="#dfn-termorcurieorabsiris">TERMorCURIEorAbsIRIs</a>,
          used for expressing relationships between a subject and some literal
          text (also a 'predicate');</dd>
        <dt><dfn class="adef" title="rel" id="A-rel">rel</dfn></dt>
        <dd>a white space separated list of <a class="datatype internalDFN" title="TERMorCURIEorAbsIRIs" href="#dfn-termorcurieorabsiris">TERMorCURIEorAbsIRIs</a>,
          used for expressing relationships between two resources ('predicates'
          in RDF terminology);</dd>
        <dt><dfn class="adef" title="resource" id="A-resource">resource</dfn></dt>
        <dd>a <a class="datatype internalDFN" title="SafeCURIEorCURIEorIRI" href="#dfn-safecurieorcurieoriri">SafeCURIEorCURIEorIRI</a> for expressing the partner
          resource of a relationship that is not intended to be navigable (e.g.,
          a 'clickable' link) (also an 'object');</dd>
        <dt><dfn class="adef" title="rev" id="A-rev">rev</dfn> </dt>
        <dd>a white space separated list of <a class="datatype internalDFN" title="TERMorCURIEorAbsIRIs" href="#dfn-termorcurieorabsiris">TERMorCURIEorAbsIRIs</a>,
          used for expressing reverse relationships between two resources (also
          'predicates');</dd>
        <dt><dfn class="adef" title="src" id="A-src">src</dfn></dt>
        <dd>a <a class="externalDFN" title="URI">URI</a> for expressing the partner resource of a
          relationship when the resource is embedded (also a 'resource object');</dd>
        <dt><dfn class="adef" title="typeof" id="A-typeof">typeof</dfn></dt>
        <dd>a white space separated list of <a class="datatype internalDFN" title="TERMorCURIEorAbsIRIs" href="#dfn-termorcurieorabsiris">TERMorCURIEorAbsIRIs</a>
          that indicate the RDF type(s) to associate with a subject;</dd>
        <dt><dfn class="adef" title="vocab" id="A-vocab">vocab</dfn></dt>
        <dd>A <a class="externalDFN" title="URI">URI</a> that defines the mapping to use when a <a class="datatype internalDFN" title="TERM" href="#dfn-term">TERM</a>
          is referenced in an attribute value. See <a href="#s_terms">General
            Use of Terms in Attributes</a> and the <a href="#s_vocab_expansion">section

            on Vocabulary Expansion</a>.</dd>
        <dt><dfn class="adef" title="inlist" id="A-inlist">inlist</dfn></dt>
        <dd>An attribute (value ignored) used to indicate that the object
          associated with a <code>rel</code> or <code>property</code>
          attribute on the same element is to be added to the list for that
          predicate. Causes a list to be created if it does not already exist</dd>
      </dl>
      <div id="white_space" typeof="bibo:Chapter" about="#white_space" class="section">
        <h3><span class="secno">5.1 </span>White space within attribute values</h3>
        <p>Many attributes accept a white space separated list of tokens. This
          specification defines white space as:</p>
        <pre><span id="P_whitespace">whitespace</span>      ::=  (#x20 | #x9 | #xD | #xA)+ 
</pre>
        <p id="C1" about="#C1" resource="http://www.w3.org/2010/02/rdfa/meetings/2010-05-20#resolution_1" rel="bibo:affirmedBy">When

          attributes accept a white space separated list of tokens, an RDFa
          Processor <em class="rfc2119" title="must">must</em> ignore any leading or trailing white space.</p>
        <p class="note">This definition is consistent with the definition found
          in [<cite><a class="bibref" rel="biblioentry" href="#bib-XML10">XML10</a></cite>].</p>
      </div>
    </div>
    <div class="normative section" id="s_curies" typeof="bibo:Chapter" about="#s_curies">
      
<!-- OddPage -->
<h2><span class="secno">6. </span>CURIE Syntax Definition</h2>
      <p>The key component of RDF is the IRI, but these are usually long and
        unwieldy. RDFa therefore supports a mechanism by which IRIs can be
        abbreviated, called 'compact URI expressions' or simply, <dfn title="curie" id="T-curie">CURIEs</dfn>.</p>
      <p> When expanded, the resulting IRI <em class="rfc2119" title="must">must</em> be a syntactically valid IRI
        [<cite><a class="bibref" rel="biblioentry" href="#bib-RFC3987">RFC3987</a></cite>]. For a more detailed explanation see <a href="#s_curieprocessing">CURIE

          and IRI Processing</a>. The <em>lexical space</em> of a CURIE is as
        defined in <a href="#P_curie">curie</a> below. The <em>value space</em>
        is the set of IRIs.</p>
      <p>A CURIE is comprised of two components, a <em><dfn title="prefix" id="T-prefix">prefix</dfn></em>
        and a <em><dfn title="reference" id="T-reference">reference</dfn></em>. The prefix is separated from the
        reference by a colon (<code>:</code>). In general use it is possible to
        omit the prefix, and so create a CURIE that makes use of the 'default
        prefix' mapping; in RDFa the 'default prefix' mapping is <code>http://www.w3.org/1999/xhtml/vocab#</code>.
        It's also possible to omit both the prefix <em>and</em> the colon, and
        so create a CURIE that contains just a reference which makes use of the
        'no prefix' mapping. This specification does not define a 'no prefix'
        mapping. RDFa Host Languages <em class="rfc2119" title="must not">must not</em> define a 'no prefix' mapping. </p>
      <p class="note"> The RDFa 'default prefix' should not be confused with the
        'default namespace' as defined in [<cite><a class="bibref" rel="biblioentry" href="#bib-XML-NAMES">XML-NAMES</a></cite>]. An RDFa Processor <em class="rfc2119" title="must
        not">must
        not</em> treat an XML-NAMES 'default namespace' declaration as if it were
        setting the 'default prefix'. </p>
      <p> The general syntax of a CURIE can be summarized as follows: </p>
      <pre><span id="P_prefix">prefix</span>      ::=   <a href="http://www.w3.org/TR/2009/REC-xml-names-20091208/#NT-NCName">NCName</a>

<span id="P_reference">reference</span>   ::=   irelative-ref (as defined in [<cite><a class="bibref" rel="biblioentry" href="#bib-RFC3987">RFC3987</a></cite>])

<span id="P_curie">curie       ::=   [ [ prefix ] ':' ] reference</span>

<span id="P_safe_curie">safe_curie  ::=   '[' [ [ prefix ] ':' ] reference ']'</span>
</pre>
      <p class="note"> The production <code>safe_curie</code> is not required,
        even in situations where an attribute value is permitted to be a CURIE
        or an IRI: An IRI that uses a scheme that is not an in-scope mapping <em>cannot</em>
        be confused with a CURIE. The concept of a safe_curie is retained for
        backward compatibility. </p>
      <p> In normal evaluation of CURIEs the following context information would
        need to be provided:</p>
      <ul>
        <li>a set of mappings from prefixes to IRIs;</li>
        <li>a mapping to use with the default prefix (for example, <code>:p</code>);</li>
        <li>a mapping to use when there is no prefix (for example, <code>p</code>);</li>
        <li>a mapping to use with the '_' prefix, which is used to generate
          unique identifiers (for example, <code>_:p</code>). </li>
      </ul>
      <p> In RDFa these values are defined as follows:</p>
      <ul>
        <li>the <strong>set of mappings from prefixes to URIs</strong> is
          provided by the current in-scope prefix declarations of the <a class="tref" title="current-element" href="#T-current-element">current

            element</a> during parsing;</li>
        <li>the <strong>mapping to use with the default prefix</strong> is the
          current default prefix mapping;</li>
        <li>the <strong>mapping to use when there is no prefix</strong> is not
          defined;</li>
        <li>the <strong>mapping to use with the '_' prefix</strong>, is not
          explicitly stated, but since it is used to generate <a class="tref" title="bnode" href="#T-bnode">bnode</a>s,


          its implementation needs to be compatible with the RDF definition and
          rules in <a href="#s_blankNodes">Referencing Blank Nodes</a>. A
          document <em class="rfc2119" title="should not">should not</em> define a mapping for the '_' prefix. A Conforming
          RDFa Processor <em class="rfc2119" title="must">must</em> ignore any definition of a mapping for the '_'
          prefix.</li>
      </ul>
      <p>A CURIE is a representation of a full IRI. The rules for determining
        that IRI are:</p>
      <ul>
        <li>If a CURIE consists of an empty <code>prefix</code> and a <code>reference</code>,
          the IRI is obtained by taking the current default prefix mapping and
          concatenating it with the <code>reference</code>. If there is no
          current default prefix mapping, then this is not a valid CURIE and
          <em class="rfc2119" title="must">must</em> be ignored. </li>
        <li>Otherwise, if a CURIE consists of a non-empty <code>prefix</code>
          and <code>reference</code>, and if there is an in-scope mapping for <code>prefix</code>
          (when compared case-insensitively), then the IRI is created by using
          that mapping, and concatenating it with the <code>reference</code>. </li>
        <li>Finally, if there is no in-scope mapping for <code>prefix</code>,
          then the value is not a CURIE. </li>
      </ul>
      <p class="note">See <a href="#s_terms">General Use of Terms in Attributes</a>
        for the way items with no colon can be interpreted in some datatypes by
        RDFa Processors.</p>
      <div class="informative section" id="why-curies-and-not-qnames" typeof="bibo:Chapter" about="#why-curies-and-not-qnames">
        <h3><span class="secno">6.1 </span>Why CURIEs and not QNames?</h3><p><em>This section is non-normative.</em></p>
        <p>In many cases, language designers have attempted to use QNames for an
          extension mechanism [<cite><a class="bibref" rel="biblioentry" href="#bib-XMLSCHEMA-2">XMLSCHEMA-2</a></cite>]. QNames do permit independent
          management of the name collection, and <em>can</em> map the names to
          a resource. Unfortunately, QNames are unsuitable in most cases because
          1) the use of QName as identifiers in attribute values and element
          content is problematic as discussed in [<cite><a class="bibref" rel="biblioentry" href="#bib-QNAMES">QNAMES</a></cite>] and 2) the syntax of
          QNames is overly restrictive and does not allow all possible IRIs to
          be expressed.</p>
        <p>A specific example of the problem this causes comes from attempting
          to define the name collection for books. In a QName, the part after
          the colon must be a valid element name, making an example such as the
          following <em>invalid</em>: <code>isbn:0321154991</code></p>
        <p>This is not a valid QName simply because &quot;0321154991&quot; is not a valid
          element name. Yet, in the example given, we don't really want to
          define a valid element name anyway. The whole reason for using a QName
          was to reference an item in a private scope - that of ISBNs. Moreover,
          in this example, we want the names within that scope to map to an IRI
          that will reveal the meaning of that ISBN. As you can see, the
          definition of QNames and this (relatively common) use case are in
          conflict with one another.</p>
        <p>This specification addresses the problem by defining CURIEs.
          Syntactically, CURIEs are a superset of QNames.</p>
        <p>Note that this specification is targeted at language designers, not
          document authors. Any language designer considering the use of QNames
          as a way to represent IRIs or unique tokens should consider instead
          using CURIEs:</p>
        <ul>
          <li>CURIEs are designed from the ground up to be used in attribute
            values. QNames are designed for unambiguously naming elements and
            attributes.</li>
          <li>CURIEs expand to IRIs, and any IRI can be represented by such an
            expansion. QNames are treated as value pairs, but even if those
            pairs are combined into a string, only a subset of IRIs can be
            represented.</li>
          <li>CURIEs can be used in non-XML grammars, and can even be used in
            XML languages that do not support XML Namespaces. QNames are limited
            to XML Namespace-aware XML Applications.</li>
        </ul>
      </div>
    </div>
    <div class="normative section" id="s_model" typeof="bibo:Chapter" about="#s_model">
      
<!-- OddPage -->
<h2><span class="secno">7. </span>Processing Model</h2>
      <p> This section looks at a generic set of processing rules for creating a
        set of triples that represent the structured data present in an RDFa
        document. Processing need not follow the DOM traversal technique
        outlined here, although the effect of following some other manner of
        processing must be the same as if the processing outlined here were
        followed. The processing model is explained using the idea of DOM
        traversal which makes it easier to describe (particularly in relation to
        the <a class="tref" title="evaluation-context" href="#T-evaluation-context">evaluation context</a>). </p>
      <div class="explanation">Note that in this section, explanations about the
        processing model or guidance to implementors are enclosed in sections
        like this.</div>
      <div id="overview" typeof="bibo:Chapter" about="#overview" class="section">
        <h3><span class="secno">7.1 </span>Overview</h3>
        <p> Evaluating a document for RDFa triples is carried out by starting at
          the document object, and then visiting each of its child elements in
          turn, in document order, applying processing rules. Processing is
          recursive in that for each child element the processor also visits
          each of <em>its</em> child elements, and applies the same processing
          rules. </p>
        <p class="note"> In some environments there will be little difference
          between starting at the root element of the document, and starting at
          the document object itself. It is defined this way because in some
          environments important information is present at the document object
          level which is not present on the root element. </p>
        <p> As processing continues, rules are applied which may generate
          triples, and may also change the <a class="tref" title="evaluation-context" href="#T-evaluation-context">evaluation context</a>
          information that will then be used when processing descendant
          elements. </p>
        <p class="note"> This specification does not say anything about what
          should happen to the triples generated, or whether more triples might
          be generated during processing than are outlined here. However, to be
          conforming, an RDFa Processor <em class="rfc2119" title="must">must</em> act as if at a minimum the rules in
          this section are applied, and a single <a class="tref" title="rdf-graph" href="#T-rdf-graph">RDF graph</a>
          produced. As described in the <a href="#processorconf">RDFa Processor
            Conformance</a> section, any additional triples generated <em class="rfc2119" title="must not">must not</em>
          appear in the <a class="tref" title="output-graph" href="#T-output-graph">output graph</a>. </p>
      </div>
      <div id="evaluation-context" typeof="bibo:Chapter" about="#evaluation-context" class="section">
        <h3><span class="secno">7.2 </span>Evaluation Context</h3>
        <p> During processing, each rule is applied using information provided
          by an <a class="tref" title="evaluation-context" href="#T-evaluation-context">evaluation context</a>. An <dfn title="initial-context" id="T-initial-context">initial context</dfn>
          is created when processing begins. That context has the following
          members:</p>
        <ul>
          <li> The <dfn title="base" id="T-base">base</dfn>. This will usually be the IRI of the
            document being processed, but it could be some other IRI, set by
            some other mechanism, such as the (X)HTML <code>base</code>
            element. The important thing is that it establishes an IRI against
            which relative paths can be resolved. </li>
          <li> The <dfn title="parent-subject" id="T-parent-subject">parent subject</dfn>. The initial
            value will be the same as the initial value of <a class="tref" title="base" href="#T-base">base</a>,
            but it will usually change during the course of processing. </li>
          <li> The <dfn title="parent-object" id="T-parent-object">parent object</dfn>. In some
            situations the object of a statement becomes the subject of any
            nested statements, and this property is used to convey this value.
            Note that this value may be a <a class="tref" title="bnode" href="#T-bnode">bnode</a>, since in some
            situations a number of nested statements are grouped together on one
            <a class="tref" title="bnode" href="#T-bnode">bnode</a>. This means that the <a class="tref" title="bnode" href="#T-bnode">bnode</a> must be
            set in the containing statement and passed down, and this property
            is used to convey this value. </li>
          <li>A list of current, in-scope <dfn title="list-of-iri-mappings" id="T-list-of-iri-mappings">IRI

              mappings</dfn>.</li>
          <li>A list of <dfn title="incomplete-triple" id="T-incomplete-triple">incomplete triple</dfn>s. A triple can be
            incomplete when no object resource is provided alongside a predicate
            that requires a resource (i.e., <a class="aref" href="#A-rel" title="rel">@rel</a> or <a class="aref" href="#A-rev" title="rev">@rev</a>).

            The triples can be completed when a resource becomes available,
            which will be when the next subject is specified (part of the
            process called <a class="tref" title="chaining" href="#T-chaining">chaining</a>).</li>
          <li>A <dfn title="list-mapping" id="T-list-mapping">list mapping</dfn> mapping IRIs to lists.</li>
          <li>The <dfn title="language" id="T-language">language</dfn>. Note that there is no default
            language.</li>
          <li>The <dfn title="term-mappings" id="T-term-mappings">term mappings</dfn>, a list of terms and their
            associated IRIs. This specification does not define an initial list.
            Host Languages <em class="rfc2119" title="may">may</em> define an initial list.</li>
          <li>The <dfn title="default-vocabulary" id="T-default-vocabulary">default vocabulary</dfn>, a value to use as the prefix
            IRI when a <a class="tref" title="term" href="#T-term">term</a> is used. This specification does not
            define an initial setting for the default vocabulary. Host Languages
            <em class="rfc2119" title="may">may</em> define an initial setting.</li>
        </ul>
        <p>During the course of processing, new <a class="tref" title="evaluation-context" href="#T-evaluation-context">evaluation context</a>s
          are created which are passed to each child element. The rules
          described below will determine the values of the items in the context.
          Additionally, some rules will cause new triples to be created by
          combining information provided by an element with information from the
          <a class="tref" title="evaluation-context" href="#T-evaluation-context">evaluation context</a>.</p>
        <p>During the course of processing a number of locally scoped values are
          needed, as follows:</p>
        <ul>
          <li>An initially empty list of <a class="tref" title="iri-mapping" href="#T-iri-mapping">IRI mapping</a>s, called the
            <dfn title="local-list-of-iri-mappings" id="T-local-list-of-iri-mappings">local list of IRI mappings</dfn>.</li>
          <li>An initially empty <dfn title="list-of-incomplete-triples" id="T-list-of-incomplete-triples">list of incomplete triples</dfn>,
            called the <dfn title="local-list-of-incomplete-triples" id="T-local-list-of-incomplete-triples">local list of incomplete triples</dfn>.</li>
          <li>An initially empty <a class="tref" title="language" href="#T-language">language</a> value.</li>
          
<!-- 
    <li>A <tdef>recurse</tdef> flag. Processing generally continues recursively through the entire tree of elements available. However,      if an author indicates that some branch of the tree should be treated as an XML literal, no further processing should      take place on that branch, and setting this flag to <code>false</code> would have that effect.    </li>
     -->

          <li> A <dfn title="skip-element" id="T-skip-element">skip element</dfn> flag, which indicates whether the <a class="tref" title="current-element" href="#T-current-element">current

              element</a> can safely be ignored since it has no relevant RDFa
            attributes. Note that descendant elements will still be processed. </li>
          <li> A <dfn title="new-subject" id="T-new-subject">new subject</dfn> value, which once calculated will set
            the <a class="tref" title="parent-subject" href="#T-parent-subject">parent subject</a> property in an <a class="tref" title="evaluation-context" href="#T-evaluation-context">evaluation
              context</a>, as well as being used to complete any <a class="tref" title="incomplete-triple" href="#T-incomplete-triple">incomplete

              triple</a>s, as described in the next section. </li>
          <li> A value for the <dfn title="current-property-value" id="T-current-property-value">current
              property value</dfn>, the literal to use when creating triples
            that have a literal object, or IRI-s in the absence of <a class="aref" href="#A-rel" title="rel">@rel</a>
            or <a class="aref" href="#A-rev" title="rev">@rev</a>. </li>
          <li> A value for the <dfn title="current-object-resource" id="T-current-object-resource">current
              object resource</dfn>, the resource to use when creating triples
            that have a resource object. </li>
          <li> A value for the <dfn title="typed-resource" id="T-typed-resource">typed resource</dfn>,
            the source for creating <code>rdf:type</code> relationships to
            types specified in <a class="aref" href="#A-datatype" title="datatype">@datatype</a>. </li>
          <li> The <dfn title="local-term-mappings" id="T-local-term-mappings">local term mappings</dfn>, a list of terms and their
            associated IRIs.</li>
          <li> The <dfn title="local-list-mapping" id="T-local-list-mapping">local list mapping</dfn>, mapping IRIs to lists</li>
          <li> A <dfn title="local-default-vocabulary" id="T-local-default-vocabulary">local default vocabulary</dfn>, an IRI to use as a
            prefix mapping when a <a class="tref" title="term" href="#T-term">term</a> is used.</li>
        </ul>
      </div>
      <div id="s_chaining" typeof="bibo:Chapter" about="#s_chaining" class="section">
        <h3><span class="secno">7.3 </span>Chaining</h3>
        <p>Statement <dfn title="chaining" id="T-chaining">chaining</dfn> is an RDFa feature that allows the
          author to link RDF statements together while avoiding unnecessary
          repetitive markup. For example, if an author were to add statements as
          children of an object that was a resource, these statements should be
          interpreted as being about that resource: </p>
        <pre class="example">&lt;div about=&quot;http://dbpedia.org/resource/Albert_Einstein&quot;&gt;
  &lt;span property=&quot;foaf:name&quot;&gt;Albert Einstein&lt;/span&gt;
  &lt;span property=&quot;dbp:dateOfBirth&quot; datatype=&quot;xsd:date&quot;&gt;1879-03-14&lt;/span&gt;
  &lt;div rel=&quot;dbp:birthPlace&quot; <span class="hilite">resource=&quot;http://dbpedia.org/resource/German_Empire&quot;</span>&gt;
    <span class="hilite">&lt;span property=&quot;dbp:conventionalLongName&quot;&gt;the German Empire&lt;/span&gt;</span>
  &lt;/div&gt;
&lt;/div&gt;</pre>
        <p> In this example we can see that an object resource
          ('German_Empire'), has become the subject for nested statements. This
          markup also illustrates the basic chaining pattern of 'A has a B has a
          C' (i.e., Einstein has a birth place of the German Empire, which has a
          long name of &quot;the German Empire&quot;). </p>
        <p>It's also possible for the subject of nested statements to provide
          the object for <em>containing</em> statements — essentially the
          reverse of the example we have just seen. To illustrate, we'll take an
          example of the type of chaining just described, and show how it could
          be marked up more efficiently. To start, we mark up the fact that
          Albert Einstein had, at some point in his life, a residence both in
          the German Empire and in Switzerland: </p>
        <pre class="example">&lt;div about=&quot;http://dbpedia.org/resource/Albert_Einstein&quot;&gt;
  <span class="hilite">&lt;div rel=&quot;dbp-owl:residence&quot; resource=&quot;http://dbpedia.org/resource/German_Empire&quot;&gt;&lt;/div&gt;</span>
  <span class="hilite">&lt;div rel=&quot;dbp-owl:residence&quot; resource=&quot;http://dbpedia.org/resource/Switzerland&quot;&gt;&lt;/div&gt;</span>
&lt;/div&gt;</pre>
        <p>Now, we show the same information, but this time we create an <a class="tref" title="incomplete-triple" href="#T-incomplete-triple">incomplete

            triple</a> from the residence part, and then use any number of
          further subjects to 'complete' that triple, as follows:</p>
        <pre class="example">&lt;div about=&quot;http://dbpedia.org/resource/Albert_Einstein&quot; rel=&quot;dbp-owl:residence&quot;&gt;
  <span class="hilite">&lt;span about=&quot;http://dbpedia.org/resource/German_Empire&quot;&gt;&lt;/span&gt;</span>
  <span class="hilite">&lt;span about=&quot;http://dbpedia.org/resource/Switzerland&quot;&gt;&lt;/span&gt;</span>
&lt;/div&gt;</pre>
        <p> In this example, the <a class="tref" title="incomplete-triple" href="#T-incomplete-triple">incomplete triple</a> actually gets
          completed twice, once for the German Empire and once for Switzerland,
          giving exactly the same information as we had in the earlier example:
        </p>
        <pre class="example">&lt;http://dbpedia.org/resource/Albert_Einstein&gt;
  dbp-owl:residence &lt;http://dbpedia.org/resource/German_Empire&gt; .
&lt;http://dbpedia.org/resource/Albert_Einstein&gt;
  dbp-owl:residence &lt;http://dbpedia.org/resource/Switzerland&gt; .</pre>
        <p> Chaining can sometimes involve elements containing relatively
          minimal markup, for example showing only one resource, or only one
          predicate. Here the <code>img</code> element is used to carry a
          picture of Einstein: </p>
        <pre class="example">&lt;div about=&quot;http://dbpedia.org/resource/Albert_Einstein&quot;&gt;
  &lt;div <span class="hilite">rel=&quot;foaf:depiction&quot;</span>&gt;
    &lt;img src=&quot;http://en.wikipedia.org/wiki/Image:Albert_Einstein_Head.jpg&quot; /&gt;
  &lt;/div&gt;
&lt;/div&gt;</pre>
        <p> When such minimal markup is used, any of the resource-related
          attributes could act as a subject or an object in the chaining: </p>
        <pre class="example">&lt;div <span class="hilite">about=&quot;http://dbpedia.org/resource/Albert_Einstein&quot;</span>&gt;
  &lt;div <span class="hilite">rel=&quot;dbp-owl:residence&quot;</span>&gt;
    &lt;span <span class="hilite">about=&quot;http://dbpedia.org/resource/German_Empire&quot;</span>&gt;&lt;/span&gt;
    &lt;span <span class="hilite">about=&quot;http://dbpedia.org/resource/Switzerland&quot;</span>&gt;&lt;/span&gt;
  &lt;/div&gt;
&lt;/div&gt;</pre>
        <p>Note that, as noted above, in many situations the <a class="aref" href="#A-property" title="property">@property</a>
          and <a class="aref" href="#A-rel" title="rel">@rel</a> are interchangeable. This is <em>not</em> true
          for chaining. Taking the first example, if that example was used as
          follows:</p>
        <pre class="example">&lt;div about=&quot;http://dbpedia.org/resource/Albert_Einstein&quot;&gt;
  &lt;span property=&quot;foaf:name&quot;&gt;Albert Einstein&lt;/span&gt;
  &lt;span property=&quot;dbp:dateOfBirth&quot; datatype=&quot;xsd:date&quot;&gt;1879-03-14&lt;/span&gt;
  &lt;div <span class="hilite">property=&quot;dbp:birthPlace&quot;</span> resource=&quot;http://dbpedia.org/resource/German_Empire&quot;&gt;
    &lt;span property=&quot;dbp:conventionalLongName&quot;&gt;the German Empire&lt;/span&gt;
  &lt;/div&gt;
&lt;/div&gt;</pre>
        <p>The subject for the 'German Empire' would remain Albert Einstein (and
          that would, of course, be an error). This is the main difference
          between <a class="aref" href="#A-property" title="property">@property</a> and <a class="aref" href="#A-rel" title="rel">@rel</a>: the latter
              induces chaining, whereas the former, usually, does not.</p>
      </div>
      <div id="s_curieprocessing" typeof="bibo:Chapter" about="#s_curieprocessing" class="section">
        <h3><span class="secno">7.4 </span>CURIE and IRI Processing</h3>
        <p> Since RDFa is ultimately a means for transporting RDF, a key concept
          is the <em>resource</em> and its manifestation as a IRI. RDF deals
          with complete IRIs (not relative paths); when converting RDFa to
          triples, any relative IRIs <em class="rfc2119" title="must">must</em> be resolved relative to the base IRI,
          using the algorithm defined in section 6.5 of RFC 3987 [<cite><a class="bibref" rel="biblioentry" href="#bib-RFC3987">RFC3987</a></cite>], <em>Reference

            Resolution</em>. The values of <a href="#s_syntax">RDFa attributes</a>
          that refer to IRIs use three different datatypes: <a class="externalDFN" title="URI">URI</a>,
          <a class="datatype internalDFN" title="SafeCURIEorCURIEorIRI" href="#dfn-safecurieorcurieoriri">SafeCURIEorCURIEorIRI</a>, or <a class="datatype internalDFN" title="TERMorCURIEorAbsIRI" href="#dfn-termorcurieorabsiri">TERMorCURIEorAbsIRI</a>.
          All these attributes are mapped, after processing, to IRIs. The
          handling of these attributes is as follows:</p>
        <dl>
          <dt>URI</dt>
          <dd>The content is a URI, and is used as such.</dd>
          <dt>SafeCURIEorCURIEorIRI</dt>
          <dd>
            <ul>
              <li>When the value is surrounded by square brackets, then the
                content within the brackets is evaluated as a CURIE according to
                the <a href="#s_curies">CURIE Syntax definition</a>. If it is
                not a valid CURIE, the value <em class="rfc2119" title="must">must</em> be ignored.</li>
              <li>Otherwise, the value is evaluated as a CURIE. If it is a valid
                CURIE, the resulting IRI is used; otherwise, the value is
                processed as an IRI. </li>
            </ul>
          </dd>
          <dt>TERMorCURIEorAbsIRI</dt>
          <dd>
            <ul id="C2" about="#C2" resource="http://www.w3.org/2010/02/rdfa/meetings/2010-07-01#resolution_3" rel="bibo:affirmedBy">
              <li>If the value is an <a class="tref" title="term" href="#T-term">term</a>
                then it is evaluated as a term according to <a href="#s_terms">General Use of Terms in Attributes</a>. Note that this step may mean
                that the value is to be ignored.</li>
              <li>If the value is a valid CURIE, then the resulting IRI is used.</li>
              <li>If the value is an absolute IRI, that value is used.</li>
              <li>Otherwise, the value is ignored.</li>
            </ul>
          </dd>
        </dl>
        <p id="C3" about="#C3" resource="http://www.w3.org/2010/02/rdfa/meetings/2010-05-20#resolution_2" rel="bibo:affirmedBy">Note

          that it is possible for all values in an attribute to be ignored. When
          that happens, the attribute <em class="rfc2119" title="must">must</em> be treated as if it were empty.</p>
        <p>For example, the full IRI for Albert Einstein on DBPedia is:</p>
        <pre class="example">http://dbpedia.org/resource/Albert_Einstein</pre>
        <p>This can be shortened by authors to make the information easier to
          manage, using a CURIE. The first step is for the author to create a
          prefix mapping that links a prefix to some leading segment of the IRI.
          In RDFa these mappings are expressed using the XML namespace syntax:</p>
        <pre class="example">&lt;div <span class="hilite">prefix=&quot;db: http://dbpedia.org/&quot;</span>&gt;
  ...
&lt;/div&gt;</pre>
        <p>Once the prefix has been established, an author can then use it to
          shorten an IRI as follows:</p>
        <pre class="example">&lt;div prefix=&quot;db: http://dbpedia.org/&quot;&gt;
  &lt;div about=&quot;<span class="hilite">db:resource/Albert_Einstein</span>&quot;&gt;
    ...
  &lt;/div&gt;
&lt;/div&gt;</pre>
        <p> The author is free to split the IRI at any point, as long as it
          begins at the left end. However, since a common use of CURIEs is to
          make available libraries of terms and values, the prefix will usually
          be mapped to some common segment that provides the most re-use, often
          provided by those who manage the library of terms. For example, since
          DBPedia contains an enormous list of resources, it is more efficient
          to create a prefix mapping that uses the base location of the
          resources:</p>
        <pre class="example">&lt;div <span class="hilite">prefix=&quot;dbr: http://dbpedia.org/resource/&quot;</span>&gt;
  &lt;div about=&quot;<span class="hilite">dbr:Albert_Einstein</span>&quot;&gt;
    ...
  &lt;/div&gt;
  &lt;div about=&quot;<span class="hilite">dbr:Baruch_Spinoza</span>&quot;&gt;
    ...
  &lt;/div&gt;
&lt;/div&gt;</pre>
        <div class="explanation"> Note that it is generally considered a bad
          idea to use relative paths in prefix declarations. Since it is
          possible that an author may ignore this guidance, it is further
          possible that the IRI obtained from a CURIE is relative. However,
          since all IRIs must be resolved relative to <a class="tref" title="base" href="#T-base">base</a> before
          being used to create triples, the use of relative paths should not
          have any effect on processing. </div>
        <div id="scoping-of-prefix-mappings" typeof="bibo:Chapter" about="#scoping-of-prefix-mappings" class="section">
          <h4><span class="secno">7.4.1 </span>Scoping of Prefix Mappings</h4>
          <p>CURIE prefix mappings are defined on the current element and its
            descendants. The inner-most mapping for a given prefix takes
            precedence. For example, the IRIs expressed by the following two
            CURIEs are different, despite the common prefix, because the prefix
            mappings are locally scoped: </p>
          <pre class="example">&lt;div <span class="hilite">prefix=&quot;dbr: http://dbpedia.org/resource/&quot;</span>&gt;
  &lt;div about=&quot;<span class="hilite">dbr:Albert_Einstein</span>&quot;&gt;
    ...
  &lt;/div&gt;
&lt;/div&gt;
&lt;div <span class="hilite">prefix=&quot;dbr: http://someotherdb.org/resource/&quot;</span>&gt;
  &lt;div about=&quot;<span class="hilite">dbr:Albert_Einstein</span>&quot;&gt;
    ...
  &lt;/div&gt;
&lt;/div&gt;</pre> </div>
        <div id="general-use-of-curies-in-attributes" typeof="bibo:Chapter" about="#general-use-of-curies-in-attributes" class="section">
          <h4><span class="secno">7.4.2 </span>General Use of CURIEs in Attributes</h4>
          <p> There are a number of ways that attributes make use of CURIEs, and
            they need to be dealt with differently. These are: </p>
          <ol>
            <li>An attribute may allow one or more values that are a mixture of
              TERMs, CURIEs, and absolute IRIs.</li>
            <li>An attribute may allow one or more values that are a mixture of
              CURIEs and IRIs. In this case any value that is not a CURIE, as
              outlined in section <a href="#s_curies">CURIE Syntax Definition</a>,
              will be processed as an IRI.</li>
            <li>If the value <em>is</em> surrounded by square brackets, then
              the content within the brackets is always evaluated according to
              the rules in <a href="#s_curies">CURIE Syntax Definition</a> -
              and if that content is not a CURIE, then the content <em class="rfc2119" title="must">must</em> be
              ignored.</li>
          </ol>
          <p class="note">An empty attribute value (e.g., <code>typeof=''</code>)
            is <em>still </em> a CURIE, and is processed as such. The rules
            for this processing are defined in <a href="#s_sequence">Sequence</a>.
            Specifically, however, an empty attribute value is <em>never</em>
            treated as a relative IRI by this specification.</p>
          <p>An example of an attribute that can contain a CURIEorIRI is <a class="aref" href="#A-about" title="about">@about</a>.
            To express an IRI directly, an author might do this:</p>
          <pre class="example">&lt;div <span class="hilite">about=&quot;http://dbpedia.org/resource/Albert_Einstein&quot;</span>&gt;
  ...
&lt;/div&gt;</pre>
          <p>whilst to express the IRI above as a CURIE they would do this:</p>
          <pre class="example">&lt;div <span class="hilite">about=&quot;dbr:Albert_Einstein&quot;</span>&gt;
  ...
&lt;/div&gt;</pre>
          <p>The author could also use a safe CURIE, as follows:</p>
          <pre class="example">&lt;div <span class="hilite">about=&quot;[dbr:Albert_Einstein]&quot;</span>&gt;
  ...
&lt;/div&gt;</pre>
          <p> Since non-CURIE values <em class="rfc2119" title="must">must</em> be ignored, the following value in <a class="aref" href="#A-about" title="about">@about</a>
            would <em>not</em> set a new subject, since <a class="aref" href="#A-about" title="about">@about</a>
            does not permit the use of <a class="datatype internalDFN" title="TERM" href="#dfn-term">TERM</a>s, and the CURIE
            has no prefix separator.</p>
          <pre class="example">&lt;div <span class="hilite">about=&quot;[Albert_Einstein]&quot;</span>&gt;
  ...
&lt;/div&gt;</pre>
          <p>However, this markup <em>would</em> set a subject, since it is not
            a CURIE, but a valid relative IRI:</p>
          <pre class="example">&lt;div <span class="hilite">about=&quot;Albert_Einstein&quot;</span>&gt;
  ...
&lt;/div&gt;</pre>
    <p>
    Note that several RDFa attributes are able to also take <a class="datatype internalDFN" title="term" href="#dfn-term">TERMS</a> as their value. 
    This is discussed in the next section.
    </p>
    </div>
    <div id="s_terms" typeof="bibo:Chapter" about="#s_terms" class="section">
    <h4><span class="secno">7.4.3 </span>General Use of Terms in Attributes</h4>
    <p>Some RDFa attributes have a datatype that permits a <dfn title="term" id="T-term">term</dfn> to be referenced.  
    RDFa defines the syntax of a term as:</p>
    <pre><span id="P_term">term     ::=  <a href="http://www.w3.org/TR/2006/REC-xml-names-20060816/#NT-NCNameStartChar">NCNameStartChar</a> <a href="#P_termChar">termChar</a>*</span>
<span id="P_termChar">termChar ::=  ( <a href="http://www.w3.org/TR/2006/REC-xml-names-20060816/#NT-NCNameChar">NameChar</a> - ':' ) | '/'</span>
    </pre>
    <p class="note">For the avoidance of doubt, this definition 
    means a 'term' in RDFa is an XML <a href="http://www.w3.org/TR/2006/REC-xml-names-20060816/#NT-NCName">NCName</a> that also permits 
    slash as a non-leading character.</p>
          <p>When an RDFa attribute permits the use of a term, and the value
            being evaluated matches the production for term above, it is
            transformed to an IRI using the following logic:</p>
          <ul>
            <li>Check if the <code>term</code> matches an item in the list of <a class="tref" title="local-term-mappings" href="#T-local-term-mappings">local
                term mappings</a>. First compare against the list <em>case-sensitively</em>,
              and if there is no match then compare <em>case-insensitively</em>.
              If there is a match, use the associated IRI.</li>
            <li>If there is a <a class="tref" title="local-default-vocabulary" href="#T-local-default-vocabulary">local default vocabulary</a> the IRI is
              obtained by concatenating that value and the <code>term</code>.</li>
            <li>If there is no <a class="tref" title="local-default-vocabulary" href="#T-local-default-vocabulary">local default vocabulary</a>, the <code>term</code>
              has no associated IRI and <em class="rfc2119" title="must">must</em> be ignored.</li>
          </ul>
          
<!--  <p class='note' id="C22" about="#C22" resource="http://www.w3.org/2010/02/rdfa/meetings/2011-01-20#ISSUE__2d_63__3a__Case__2d_insensitive_term_matching" rel='bibo:affirmedBy'>In the event that multiple <code>term</code>s are defined that differ only in case (e.g., 'Agent', 'agent', and 'AGENT'), if a reference is made which DOES NOT match case-sensitively (e.g., typeof='AGENt'), the results are UNSPECIFIED.</p>  -->

        </div>
        <div id="use-of-curies-in-specific-attributes" typeof="bibo:Chapter" about="#use-of-curies-in-specific-attributes" class="section">
          <h4><span class="secno">7.4.4 </span>Use of CURIEs in Specific Attributes</h4>
          <p> The general rules discussed in the previous sections apply to the
            RDFa attributes in the following ways: </p>
          <ul>
            <li><a class="aref" href="#A-about" title="about">@about</a> and <a class="aref" href="#A-resource" title="resource">@resource</a> support the
              datatype <a class="datatype internalDFN" title="SafeCURIEorCURIEorIRI" href="#dfn-safecurieorcurieoriri">SafeCURIEorCURIEorIRI</a> - allowing a
              SafeCURIE, a CURIE, or an IRI.</li>
            <li><a class="aref" href="#A-href" title="href">@href</a> and <a class="aref" href="#A-src" title="src">@src</a> are as defined in the
              Host Language (e.g., XHTML), and support only an IRI.</li>
            <li><a class="aref" href="#A-vocab" title="vocab">@vocab</a> supports an IRI.</li>
            <li><a class="aref" href="#A-datatype" title="datatype">@datatype</a> supports the datatype <a class="datatype internalDFN" title="TERMorCURIEorAbsIRI" href="#dfn-termorcurieorabsiri">TERMorCURIEorAbsIRI</a>
              - allowing a single Term, CURIE, or Absolute IRI.</li>
            <li><a class="aref" href="#A-property" title="property">@property</a>, <a class="aref" href="#A-typeof" title="typeof">@typeof</a>, <a class="aref" href="#A-rel" title="rel">@rel</a>,
              and <a class="aref" href="#A-rev" title="rev">@rev</a> support the datatype <a class="datatype internalDFN" title="TERMorCURIEorAbsIRIs" href="#dfn-termorcurieorabsiris">TERMorCURIEorAbsIRIs</a>
              - allowing one or more Terms, CURIEs, or Absolute IRIs.</li>
          </ul>
          <p> Any value that matches a defined term <em class="rfc2119" title="must">must</em> be expanded into a
            reference to the corresponding IRI. For example in [<cite><a class="bibref" rel="biblioentry" href="#bib-XHTML-RDFA">XHTML-RDFA</a></cite>]
            the following examples: </p>
          <pre class="example">&lt;link rel=&quot;<span class="hilite">next</span>&quot; href=&quot;http://example.org/page2.html&quot; /&gt;
&lt;link rel=&quot;<span class="hilite">xhv:next</span>&quot; href=&quot;http://example.org/page2.html&quot; /&gt;</pre>
          <p>would each generate the following triple:</p>
          <pre class="example">&lt;&gt; &lt;http://www.w3.org/1999/xhtml/vocab#next&gt; &lt;http://example.org/page2.html&gt; .</pre> </div>
        <div id="s_blankNodes" typeof="bibo:Chapter" about="#s_blankNodes" class="section">
          <h4><span class="secno">7.4.5 </span>Referencing Blank Nodes</h4>
          <p>In RDFa, it is possible to establish relationships using various
            types of resource references, including <a class="tref" title="bnode" href="#T-bnode">bnode</a>s. If a
            subject or object is defined using a CURIE, and that CURIE
            explicitly names a <a class="tref" title="bnode" href="#T-bnode">bnode</a>, then a Conforming Processor
            <em class="rfc2119" title="must">must</em> create the <a class="tref" title="bnode" href="#T-bnode">bnode</a> when it is encountered during
            parsing. The RDFa Processor <em class="rfc2119" title="must">must</em> also ensure that no <a class="tref" title="bnode" href="#T-bnode">bnode</a>
            created automatically (as a result of <a class="tref" title="chaining" href="#T-chaining">chaining</a>) has a
            name that collides with a <a class="tref" title="bnode" href="#T-bnode">bnode</a> that is defined by
            explicit reference in a CURIE.</p>
          <p>Consider the following example:</p>
          <pre class="example">&lt;link <span class="hilite">about=&quot;_:john&quot;</span> rel=&quot;foaf:mbox&quot;
  href=&quot;mailto:john@example.org&quot; /&gt;
&lt;link <span class="hilite">about=&quot;_:sue&quot;</span> rel=&quot;foaf:mbox&quot;
  href=&quot;mailto:sue@example.org&quot; /&gt;
&lt;link <span class="hilite">about=&quot;_:john&quot;</span> rel=&quot;foaf:knows&quot;
  resource=&quot;_:sue&quot; /&gt;</pre>
          <p>In the above fragment, two <a class="tref" title="bnode" href="#T-bnode">bnodes</a> are
            explicitly created as the subject of triples. Those <a class="tref" title="bnode" href="#T-bnode">bnodes</a>
            are then referenced to demonstrate the relationship between the
            parties. After processing, the following triples will be generated:</p>
          <pre class="example">_:john foaf:mbox &lt;mailto:john@example.org&gt; .
_:sue foaf:mbox &lt;mailto:sue@example.org&gt; .
_:john foaf:knows _:sue .</pre>
          <p class="note" id="C18" about="#C18" resource="http://www.w3.org/2010/02/rdfa/meetings/2010-10-21#resolution_3" rel="bibo:affirmedBy">
            RDFa Processors use, internally, implementation-dependent
            identifiers for bnodes. When triples are <em>retrieved</em>, new
            bnode indentifiers are used, which usually bear no relation to the
            original identifiers. However, implementations do ensure that these
            generated bnode identifiers are consistent: each bnode will have its
            own identifier, all references to a particular bnode will use the
            same identifier, and different bnodes will have different
            identifiers. </p>
          <p>As a special case, <code>_:</code> is also a valid reference for <em>one</em>
            specific <a class="tref" title="bnode" href="#T-bnode">bnode</a>.</p>
        </div>
      </div>
      <div id="s_sequence" typeof="bibo:Chapter" about="#s_sequence" class="section">
        <h3><span class="secno">7.5 </span>Sequence</h3>
        <p> Processing would normally begin after the document to be parsed has
          been completely loaded. However, there is no requirement for this to
          be the case, and it is certainly possible to use a stream-based
          approach, such as SAX [<cite><a class="bibref" rel="biblioentry" href="#bib-SAX">SAX</a></cite>] to extract the RDFa information.
          However, if some approach other than the DOM traversal technique
          defined here is used, it is important to ensure that Host
          Language-specific processing rules are applied (e.g., XHTML+RDFa
          [<cite><a class="bibref" rel="biblioentry" href="#bib-XHTML-RDFA">XHTML-RDFA</a></cite>] indicates the <code>base</code> element can be used,
          and <code>base</code> will affect the interpretation of IRIs in <code>meta</code>
          or <code>link</code> elements even if those elements are before the <code>base</code>
          element in the stream). </p>
        <p id="PS-initial-context"> At the beginning of processing, an initial <dfn title="evaluation-context" id="T-evaluation-context">evaluation

            context</dfn> is created, as follows:</p>
        <ul>
          <li>the <a class="tref" title="base" href="#T-base">base</a> is set to the IRI of the document (or
            another value specified in a language specific manner such as the
            HTML <code>base</code> element); </li>
          <li>the <a class="tref" title="parent-subject" href="#T-parent-subject">parent subject</a> is set to the <a class="tref" title="base" href="#T-base">base</a>
            value;</li>
          <li>the <a class="tref" title="parent-object" href="#T-parent-object">parent object</a> is set to null;</li>
          <li>the <a class="tref" title="list-of-incomplete-triples" href="#T-list-of-incomplete-triples">list of incomplete triples</a> is empty;</li>
          <li>the <a class="tref" title="list-mapping" href="#T-list-mapping">list mapping</a> is empty;</li>
          <li>the <a class="tref" title="language" href="#T-language">language</a> is set to null.</li>
          <li id="C12" about="#C12" resource="http://www.w3.org/2010/02/rdfa/meetings/2010-07-22#resolution_2" rel="bibo:affirmedBy">
            the <a class="tref" title="list-of-iri-mappings" href="#T-list-of-iri-mappings">list of IRI mappings</a> is empty (or a list defined
            in the <a href="#s_initialcontexts">initial context</a> of the Host
            Language).</li>
          <li id="C13" about="#C13" resource="http://www.w3.org/2010/02/rdfa/meetings/2010-07-22#resolution_2" rel="bibo:affirmedBy">the

            <a class="tref" title="term-mappings" href="#T-term-mappings">term mappings</a> is set to null (or a list defined in the
            <a href="#s_initialcontexts">initial context</a> of the Host
            Language).</li>
          <li id="C14" about="#C14" resource="http://www.w3.org/2010/02/rdfa/meetings/2010-07-22#resolution_2" rel="bibo:affirmedBy">the

            <a class="tref" title="default-vocabulary" href="#T-default-vocabulary">default vocabulary</a> is set to null (or a IRI defined in
            the <a href="#s_initialcontexts">initial context</a> of the Host
            Language).</li>
        </ul>
        <p> Processing begins by applying the processing rules below to the
          document object, in the context of this initial <a class="tref" title="evaluation-context" href="#T-evaluation-context">evaluation
            context</a>. All elements in the tree are also processed
          according to the rules described below, depth-first, although the <a class="tref" title="evaluation-context" href="#T-evaluation-context">evaluation

            context</a> used for each set of rules will be based on previous
          rules that may have been applied.</p>
        <p class="note">This specification defines processing rules for optional
          attributes that may not be present in all Host Languages (e.g., <code>@xmlns:</code>).


          If these attributes are not supported in the Host Language, then the
          corresponding processing rules are not relevant for that language.</p>
        <p> The processing rules are:</p>
        <ol>
          <li id="PS-initialization"> First, the local values are initialized,
            as follows:
            <ul>
              
<!--             <li>the <tref>recurse</tref> flag is set to 'true';</li>  -->

              <li>the <a class="tref" title="skip-element" href="#T-skip-element">skip element</a> flag is set to 'false';</li>
              <li><a class="tref" title="new-subject" href="#T-new-subject">new subject</a> is set to null;</li>
              <li><a class="tref" title="current-object-resource" href="#T-current-object-resource">current object resource</a> is set to null;</li>
              <li><a class="tref" title="typed-resource" href="#T-typed-resource">typed resource</a> is set to null;</li>
              <li>the <a class="tref" title="local-list-of-iri-mappings" href="#T-local-list-of-iri-mappings">local list of IRI mappings</a> is set to the
                list of IRI mappings from the <a class="tref" title="evaluation-context" href="#T-evaluation-context">evaluation context</a>;</li>
              <li>the <a class="tref" title="local-list-of-incomplete-triples" href="#T-local-list-of-incomplete-triples">local list of incomplete triples</a> is set to
                null;</li>
              <li>the <a class="tref" title="list-mapping" href="#T-list-mapping">list mapping</a> is set to (a reference of) the
                list mapping from the <a class="tref" title="evaluation-context" href="#T-evaluation-context">evaluation context</a>;</li>
              <li>the <a class="tref" title="current-language" href="#T-current-language">current language</a> value is set to the <a class="tref" title="language" href="#T-language">language</a>
                value from the <a class="tref" title="evaluation-context" href="#T-evaluation-context">evaluation context</a>.</li>
              <li>the <a class="tref" title="local-term-mappings" href="#T-local-term-mappings">local term mappings</a> is set to the <a class="tref" title="term-mappings" href="#T-term-mappings">term

                  mappings</a> from the <a class="tref" title="evaluation-context" href="#T-evaluation-context">evaluation context</a>.</li>
              <li>the <a class="tref" title="local-default-vocabulary" href="#T-local-default-vocabulary">local default vocabulary</a> is set to the <a class="tref" title="default-vocabulary" href="#T-default-vocabulary">default

                  vocabulary</a> from the <a class="tref" title="evaluation-context" href="#T-evaluation-context">evaluation context</a>.</li>
            </ul>
            <div class="explanation"> Note that some of the local variables are
              temporary containers for values that will be passed to descendant
              elements via an <a class="tref" title="evaluation-context" href="#T-evaluation-context">evaluation context</a>. In some cases
              the containers will have the same name, so to make it clear which
              is being acted upon in the following steps, the local version of
              an item will generally be referred to as such. </div>
          </li>
          <li id="PS-default-vocabulary"> Next the <dfn title="current-element" id="T-current-element">current element</dfn>
            is examined for any change to the <a class="tref" title="default-vocabulary" href="#T-default-vocabulary">default vocabulary</a>
            via <a class="aref" href="#A-vocab" title="vocab">@vocab</a>. If <a class="aref" href="#A-vocab" title="vocab">@vocab</a> is present and
            contains a value, its value updates the <a class="tref" title="local-default-vocabulary" href="#T-local-default-vocabulary">local default
              vocabulary</a>. If the value is empty, then the <a class="tref" title="local-default-vocabulary" href="#T-local-default-vocabulary">local
              default vocabulary</a> <em class="rfc2119" title="must">must</em> be reset to the Host Language
            defined default (if any).
            <div class="explanation"> The value of <a class="aref" href="#A-vocab" title="vocab">@vocab</a> is used
              to generate a triple as follows:
              <dl>
                <dt>subject</dt>
                <dd><a class="tref" title="base" href="#T-base">base</a></dd>
                <dt>predicate</dt>
                <dd><code>http://www.w3.org/ns/rdfa#usesVocabulary</code></dd>
                <dt>object</dt>
                <dd>value from <a class="aref" href="#A-vocab" title="vocab">@vocab</a></dd>
              </dl>
            </div>
            <div class="explanation"> A Host Language is not required to define
              a default vocabulary. In such a case, setting <a class="aref" href="#A-vocab" title="vocab">@vocab</a>
              to the empty value has the effect of clearing the <a class="tref" title="local-default-vocabulary" href="#T-local-default-vocabulary">local
                default vocabulary</a>. </div>
          </li>
          <li id="PS-IRI-mappings">Next, the <a class="tref" title="current-element" href="#T-current-element">current element</a> is
            examined for <dfn title="iri-mapping" id="T-iri-mapping">IRI mapping</dfn>s and these are added to the <a class="tref" title="local-list-of-iri-mappings" href="#T-local-list-of-iri-mappings">local

              list of IRI mappings</a>. Note that a <a class="tref" title="iri-mapping" href="#T-iri-mapping">IRI mapping</a>
            will simply overwrite any current mapping in the list that has the
            same name;
            <div class="explanation"> Mappings are defined via <a class="aref" href="#A-prefix" title="prefix">@prefix</a>.
              <span id="C21" about="#C21" resource="http://www.w3.org/2010/02/rdfa/meetings/2011-01-13#ISSUE__2d_62__3a____40_prefix_processing_order" rel="bibo:affirmedBy">Values

                in this attribute are evaluated from beginning to end (e.g.,
                left to right in typical documents).</span> <span id="C23" about="#C23" rel="bibo:affirmedBy" resource="http://www.w3.org/2010/02/rdfa/meetings/2011-02-14#resolution_3">For

                backward compatibility, RDFa Processors <em class="rfc2119" title="should">should</em> also permit the
                definition of mappings via <span class="aref">@xmlns</span>. In
                this case, the value to be mapped is set by the XML namespace
                prefix, and the value to map is the value of the attribute — an
                IRI. (Note that prefix mapping via <span class="aref">@xmlns</span>
                is deprecated, and may be removed in a future version of this
                specification.)</span> When <span class="aref">xmlns</span> is
              supported, such mappings <em class="rfc2119" title="must">must</em> be processed before processing an
              mappings from <a class="aref" href="#A-prefix" title="prefix">@prefix</a> on the same element. <span id="C5" about="#C5" resource="http://www.w3.org/2010/02/rdfa/meetings/2010-05-13#resolution_1" rel="bibo:affirmedBy">
                Regardless of how the mapping is declared, the value to be
                mapped <em class="rfc2119" title="must">must</em> be converted to lower case</span>, and the IRI is
              not processed in any way; in particular if it is a relative path
              it <em class="rfc2119" title="must not">must not</em> be resolved against the current <a class="tref" title="base" href="#T-base">base</a>.
              Authors <em class="rfc2119" title="should not">should not</em> use relative paths as the IRI. </div>
          </li>
          <li id="PS-language" about="#PS-language" resource="http://www.w3.org/2010/02/rdfa/meetings/2010-05-13#resolution_3" rel="bibo:affirmedBy">
            The <a class="tref" title="current-element" href="#T-current-element">current element</a> is also parsed for any language
            information, and if present, <a class="tref" title="current-language" href="#T-current-language">current language</a> is set
            accordingly;
            <div class="explanation"> Host Languages that incorporate RDFa <em class="rfc2119" title="may">may</em>
              provide a mechanism for specifying the natural language of an
              element and its contents (e.g., XML provides the general-purpose
              XML attribute <span class="aref">@xml:lang</span>). </div>
          </li>
          <li id="PS-new-subject"> If the <a class="tref" title="current-element" href="#T-current-element">current element</a> contains
            no <a class="aref" href="#A-rel" title="rel">@rel</a> or <a class="aref" href="#A-rev" title="rev">@rev</a> attribute, then the next
            step is to establish a value for <a class="tref" title="new-subject" href="#T-new-subject">new subject</a>. This
            step has two possible alternatives.
            <ol>
              <li id="GK1" about="#GK1" resource="http://www.w3.org/2010/02/rdfa/meetings/2011-11-10#resolution_2" rel="bibo:affirmedBy">
                If the <a class="tref" title="current-element" href="#T-current-element">current element</a> contains the <a class="aref" href="#A-property" title="property">@property</a>
                attribute, but does <em>not</em> contains neither the <a class="aref" href="#A-content" title="content">@content</a>
                nor <a class="aref" href="#A-datatype" title="datatype">@datatype</a> attributes, then
                <div class="explanation"> <a class="tref" title="new-subject" href="#T-new-subject">new subject</a> is set to
                  the IRI obtained from the first match from the following rule:
                  <ul>
                    <li>by using the IRI from <a class="aref" href="#A-about" title="about">@about</a>, if present,
                      obtained according to the section on <a href="#s_curieprocessing">CURIE

                        and IRI Processing</a>;</li>
                  </ul>
                  <p>If no IRI is provided by a resource attribute, then the
                    first match from the following rules will apply:</p>
                  <ul>
                    <li>if the element is the root element of the document, then
                      act as if there is an empty <a class="aref" href="#A-about" title="about">@about</a> present,
                      and process it according to the rule for <a class="aref" href="#A-about" title="about">@about</a>,
                      above;</li>
                    <li><em>otherwise</em>, if <a class="tref" title="parent-object" href="#T-parent-object">parent object</a> is
                      present, <a class="tref" title="new-subject" href="#T-new-subject">new subject</a> is set to the value of
                      <a class="tref" title="parent-object" href="#T-parent-object">parent object</a>.</li>
                  </ul>
                  <p>If <a class="aref" href="#A-typeof" title="typeof">@typeof</a> is present:</p>
                  <ul>
                    <li>if the element contains a <a class="aref" href="#A-href" title="href">@href</a>, <a class="aref" href="#A-src" title="src">@src</a>,
                      or <a class="aref" href="#A-resource" title="resource">@resource</a> attribute, the value of <a class="tref" title="typed-resource" href="#T-typed-resource">typed

                        resource</a> is set the IRI from the first value from
                      this set of attributes, obtained according to the section
                      on <a href="#s_curieprocessing">CURIE and IRI Processing</a>;</li>
                    <li>otherwise, the value of <a class="tref" title="typed-resource" href="#T-typed-resource">typed resource</a> is
                      set to a newly created <a class="tref" title="bnode" href="#T-bnode">bnode</a></li>
                    <li>The value of the <a class="tref" title="current-object-resource" href="#T-current-object-resource">current object resource</a>
                      is set to the value of <a class="tref" title="typed-resource" href="#T-typed-resource">typed resource</a></li>
                  </ul>
                </div>
              </li>
              <li><em>otherwise</em>:
                <div class="explanation">
                  <p>if the element contains a <a class="aref" href="#A-about" title="about">@about</a>, <a class="aref" href="#A-href" title="href">@href</a>,
                    <a class="aref" href="#A-src" title="src">@src</a>, or <a class="aref" href="#A-resource" title="resource">@resource</a> attribute, <a class="tref" title="new-subject" href="#T-new-subject">new

                      subject</a> is set to the IRI obtained from the first
                    value from this set of attributes, obtained according to the
                    section on <a href="#s_curieprocessing">CURIE and IRI
                      Processing</a>.</p>
                  <p>If no IRI is provided by a resource attribute, then the
                    first match from the following rules will apply:</p>
                  <ul>
                    <li>if the element is the root element of the document, then
                      act as if there is an empty <a class="aref" href="#A-about" title="about">@about</a> present,
                      and process it according to the rule for <a class="aref" href="#A-about" title="about">@about</a>,
                      above;</li>
                    <li>if <a class="aref" href="#A-typeof" title="typeof">@typeof</a> is present, then <a class="tref" title="new-subject" href="#T-new-subject">new
                        subject</a> is set to be a newly created <a class="tref" title="bnode" href="#T-bnode">bnode</a>.</li>
                    <li><em>otherwise</em>, if <a class="tref" title="parent-object" href="#T-parent-object">parent object</a> is
                      present, <a class="tref" title="new-subject" href="#T-new-subject">new subject</a> is set to the value of
                      <a class="tref" title="parent-object" href="#T-parent-object">parent object</a>. Additionally, if <a class="aref" href="#A-property" title="property">@property</a>
                      is <em>not</em> present then the <a class="tref" title="skip-element" href="#T-skip-element">skip element</a>
                      flag is set to 'true';</li>
                  </ul>
                  <p id="GK2" about="#GK2" resource="http://www.w3.org/2010/02/rdfa/meetings/2011-11-10#resolution_2" rel="bibo:affirmedBy">if

                    <a class="aref" href="#A-typeof" title="typeof">@typeof</a> is present, set the <a class="tref" title="typed-resource" href="#T-typed-resource">typed
                      resource</a> to the value of <a class="tref" title="new-subject" href="#T-new-subject">new subject</a>.</p>
                </div>
              </li>
            </ol>
          </li>
          <li id="PS-new-subject-and-object"> If the <a class="tref" title="current-element" href="#T-current-element">current element</a>
            <em>does</em> contain a <a class="aref" href="#A-rel" title="rel">@rel</a> or <a class="aref" href="#A-rev" title="rev">@rev</a>
            attribute, then the next step is to establish <em>both</em> a value
            for <a class="tref" title="new-subject" href="#T-new-subject">new subject</a> and a value for <a class="tref" title="current-object-resource" href="#T-current-object-resource">current object
              resource</a>:
            <div class="explanation"> <a class="tref" title="new-subject" href="#T-new-subject">new subject</a> is set to the
              IRI obtained from the first match from the following rules:
              <ul>
                <li>by using the IRI from <a class="aref" href="#A-about" title="about">@about</a>, if present,
                  obtained according to the section on <a href="#s_curieprocessing">CURIE

                    and IRI Processing</a>;</li>
              </ul>
              <p id="GK3" about="#GK3" resource="http://www.w3.org/2010/02/rdfa/meetings/2011-11-10#resolution_2" rel="bibo:affirmedBy">
                if the <a class="aref" href="#A-typeof" title="typeof">@typeof</a> attribute is present, set <a class="tref" title="typed-resource" href="#T-typed-resource">typed

                  resource</a> to <a class="tref" title="new-subject" href="#T-new-subject">new subject</a>.</p>
              <p>If no IRI is provided then the first match from the following
                rules will apply:</p>
              <ul>
                <li>if the element is the root element of the document then act
                  as if there is an empty <a class="aref" href="#A-about" title="about">@about</a> present, and
                  process it according to the rule for <a class="aref" href="#A-about" title="about">@about</a>,
                  above;</li>
                <li><em>otherwise</em>, if <a class="tref" title="parent-object" href="#T-parent-object">parent object</a> is
                  present, <a class="tref" title="new-subject" href="#T-new-subject">new subject</a> is set to that.</li>
              </ul>
              <p>Then the <a class="tref" title="current-object-resource" href="#T-current-object-resource">current object resource</a> is set to the
                IRI obtained from the first match from the following rules:</p>
              <ul>
                <li>by using the IRI from <a class="aref" href="#A-resource" title="resource">@resource</a>, if present,
                  obtained according to the section on <a href="#s_curieprocessing">CURIE

                    and IRI Processing</a>;</li>
                <li><em>otherwise</em>, by using the URI from <a class="aref" href="#A-href" title="href">@href</a>,
                  if present, obtained according to the section on <a href="#s_curieprocessing">CURIE

                    and URI Processing</a>.</li>
                <li><em>otherwise</em>, by using the IRI from <a class="aref" href="#A-src" title="src">@src</a>,
                  if present, obtained according to the section on <a href="#s_curieprocessing">CURIE

                    and IRI Processing</a>.</li>
                <li><em>otherwise</em>, if <a class="aref" href="#A-typeof" title="typeof">@typeof</a> is present and <a class="aref" href="#A-about" title="about">@about</a>
                  is not, use a newly created <a class="tref" title="bnode" href="#T-bnode">bnode</a>.</li>
              </ul>
              <p id="GK4" about="#GK4" resource="http://www.w3.org/2010/02/rdfa/meetings/2011-11-10#resolution_2" rel="bibo:affirmedBy">
                If <a class="aref" href="#A-typeof" title="typeof">@typeof</a> is present and <a class="aref" href="#A-about" title="about">@about</a> is
                not, set <a class="tref" title="typed-resource" href="#T-typed-resource">typed resource</a> to <a class="tref" title="current-object-resource" href="#T-current-object-resource">current object
                  resource</a>.</p>
              <p>Note that final value of the <a class="tref" title="current-object-resource" href="#T-current-object-resource">current object resource</a>
                will either be null (from initialization) or a full IRI.</p>
            </div>
          </li>
          <li id="PS-subject-types" about="#PS-subject-types" resource="http://www.w3.org/2010/02/rdfa/meetings/2011-11-10#resolution_2" rel="bibo:affirmedBy">
            If in any of the previous steps a <a class="tref" title="typed-resource" href="#T-typed-resource">typed resource</a> was
            set to a non-null value, it is now used to provide a subject for
            type values;
            <div class="explanation"> One or more 'types' for the <a class="tref" title="typed-resource" href="#T-typed-resource">typed
                resource</a> can be set by using <a class="aref" href="#A-typeof" title="typeof">@typeof</a>. If
              present, the attribute may contain one or more IRIs, obtained
              according to the section on <a href="#s_curieprocessing">CURIE
                and IRI Processing</a>, each of which is used to generate a
              triple as follows:
              <dl>
                <dt>subject</dt>
                <dd><a class="tref" title="typed-resource" href="#T-typed-resource">typed resource</a></dd>
                <dt>predicate</dt>
                <dd>http://www.w3.org/1999/02/22-rdf-syntax-ns#type</dd>
                <dt>object</dt>
                <dd>full IRI of 'type'</dd>
              </dl>
            </div>
          </li>
          <li id="PS-empty-list-mapping"> If in any of the previous steps a <a class="tref" title="new-subject" href="#T-new-subject">new

              subject</a> was set to a non-null value <em>different</em>
            from the <a class="tref" title="parent-object" href="#T-parent-object">parent object</a>;
            <div class="explanation"> The <a class="tref" title="list-mapping" href="#T-list-mapping">list mapping</a> taken from
              the <a class="tref" title="evaluation-context" href="#T-evaluation-context">evaluation context</a> is set to a new, empty
              mapping. </div>
          </li>
          <li id="PS-generate-triples"> If in any of the previous steps a <a class="tref" title="current-object-resource" href="#T-current-object-resource">current

              object resource</a> was set to a non-null value, it is now used
            to generate triples and add entries to the <a class="tref" title="local-list-mapping" href="#T-local-list-mapping">local list mapping</a>:
            <div class="explanation"> If the element contains <em>both</em> the
              <a class="aref" href="#A-inlist" title="inlist">@inlist</a> and the <a class="aref" href="#A-rel" title="rel">@rel</a> attributes: the <a class="aref" href="#A-rel" title="rel">@rel</a>
              may contain one or more IRIs, obtained according to the section on
              <a href="#s_curieprocessing">CURIE and IRI Processing</a> each of
              which is used to add an entry to the <a class="tref" title="list-mapping" href="#T-list-mapping">list mapping</a> as
              follows:
              <ul>
                <li>if the <a class="tref" title="local-list-mapping" href="#T-local-list-mapping">local list mapping</a> does not contain a
                  list associated with the IRI, instantiate a new list and add
                  to local list mappings</li>
                <li>add the <a class="tref" title="current-object-resource" href="#T-current-object-resource">current object resource</a> to the list
                  associated with the IRI in the <a class="tref" title="local-list-mapping" href="#T-local-list-mapping">local list mapping</a></li>
              </ul>
            </div>
            <div class="explanation"> Predicates for the <a class="tref" title="current-object-resource" href="#T-current-object-resource">current object
                resource</a> can be set by using one or both of the <a class="aref" href="#A-rel" title="rel">@rel</a>
              and the <a class="aref" href="#A-rev" title="rev">@rev</a> attributes but, in case of the <a class="aref" href="#A-rel" title="rel">@rel</a>
              attribute, only if the <a class="aref" href="#A-inlist" title="inlist">@inlist</a> is <em>not</em>
              present:
              <ul>
                <li> If present, <a class="aref" href="#A-rel" title="rel">@rel</a> may contain one or more IRIs,
                  obtained according to the section on <a href="#s_curieprocessing">CURIE

                    and IRI Processing</a> each of which is used to generate a
                  triple as follows:
                  <dl>
                    <dt>subject</dt>
                    <dd><a class="tref" title="new-subject" href="#T-new-subject">new subject</a></dd>
                    <dt>predicate</dt>
                    <dd>full IRI</dd>
                    <dt>object</dt>
                    <dd><a class="tref" title="current-object-resource" href="#T-current-object-resource">current object resource</a></dd>
                  </dl>
                </li>
                <li> If present, <a class="aref" href="#A-rev" title="rev">@rev</a> may contain one or more IRIs,
                  obtained according to the section on <a href="#s_curieprocessing">CURIE

                    and IRI Processing</a> each of which is used to generate a
                  triple as follows:
                  <dl>
                    <dt>subject</dt>
                    <dd><a class="tref" title="current-object-resource" href="#T-current-object-resource">current object resource</a></dd>
                    <dt>predicate</dt>
                    <dd>full IRI</dd>
                    <dt>object</dt>
                    <dd><a class="tref" title="new-subject" href="#T-new-subject">new subject</a></dd>
                  </dl>
                </li>
              </ul>
            </div>
          </li>
          <li id="PS-incomplete-triples"> If however <a class="tref" title="current-object-resource" href="#T-current-object-resource">current object
              resource</a> was set to null, but there are predicates present,
            then they must be stored as <a class="tref" title="incomplete-triple" href="#T-incomplete-triple">incomplete triple</a>s,
            pending the discovery of a subject that can be used as the object.
            Also, <a class="tref" title="current-object-resource" href="#T-current-object-resource">current object resource</a> should be set to a newly
            created <a class="tref" title="bnode" href="#T-bnode">bnode</a>;
            <div class="explanation"> Predicates for <a class="tref" title="incomplete-triple" href="#T-incomplete-triple">incomplete triple</a>s
              can be set by using one or both of the <a class="aref" href="#A-rel" title="rel">@rel</a> and <a class="aref" href="#A-rev" title="rev">@rev</a>
              attributes:
              <ul>
                <li> If present, <a class="aref" href="#A-rel" title="rel">@rel</a> must contain one or more
                  IRIs, obtained according to the section on <a href="#s_curieprocessing">CURIE

                    and IRI Processing</a> each of which is added to the <a class="tref" title="local-list-of-incomplete-triples" href="#T-local-list-of-incomplete-triples">local

                    list of incomplete triples</a> as follows:
                  <ul>
                    <li> If the element contains the <a class="aref" href="#A-inlist" title="inlist">@inlist</a>
                      attribute, then
                      <ul>
                        <li>if the <a class="tref" title="local-list-mapping" href="#T-local-list-mapping">local list mapping</a> does not
                          contain a list associated with the IRI, instantiate a
                          new list and add to local list mappings. </li>
                        <li>Add:
                          <dl>
                            <dt>list</dt>
                            <dd>list from <a class="tref" title="local-list-mapping" href="#T-local-list-mapping">local list mapping</a> for
                              this IRI</dd>
                            <dt>direction</dt>
                            <dd>none</dd>
                          </dl>
                        </li>
                      </ul>
                    </li>
                    <li>Otherwise add:
                      <ul>
                        <li>
                          <dl>
                            <dt>predicate</dt>
                            <dd>full IRI</dd>
                            <dt>direction</dt>
                            <dd>forward</dd>
                          </dl>
                        </li>
                      </ul>
                    </li>
                  </ul>
                </li>
                <li> If present, <a class="aref" href="#A-rev" title="rev">@rev</a> must contain one or more
                  IRIs, obtained according to the section on <a href="#s_curieprocessing">CURIE

                    and IRI Processing</a>, each of which is added to the <a class="tref" title="local-list-of-incomplete-triples" href="#T-local-list-of-incomplete-triples">local

                    list of incomplete triples</a> as follows:
                  <dl>
                    <dt>predicate</dt>
                    <dd>full IRI</dd>
                    <dt>direction</dt>
                    <dd>reverse</dd>
                  </dl>
                </li>
              </ul>
            </div>
          </li>
          <li id="PS-current-object-literal"> The next step of the iteration is
            to establish any <a class="tref" title="current-property-value" href="#T-current-property-value">current property value</a>;
            <div class="explanation"> Predicates for the <a class="tref" title="current-property-value" href="#T-current-property-value">current property
                value</a> can be set by using <a class="aref" href="#A-property" title="property">@property</a>. If
              present, one or more IRIs are obtained according to the section on
              <a href="#s_curieprocessing">CURIE and IRI Processing</a>, and
              then the actual literal value is obtained as follows:
              <ul>
                <li> as a <a class="tref" title="typed-literal" href="#T-typed-literal">typed literal</a> if <a class="aref" href="#A-datatype" title="datatype">@datatype</a>
                  is present, does not have an empty value according to the
                  section on <a href="#s_curieprocessing">CURIE and IRI
                    Processing</a>, and is not set to <code>XMLLiteral</code>
                  in the vocabulary <code>http://www.w3.org/1999/02/22-rdf-syntax-ns#</code>.
                  <p>The actual literal is either the value of <a class="aref" href="#A-content" title="content">@content</a>
                    (if present) <em>or</em> a string created by concatenating
                    the value of all descendant text nodes, of the <a class="tref" title="current-element" href="#T-current-element">current

                      element</a> in turn. The final string includes the
                    datatype IRI, as described in [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-CONCEPTS">RDF-CONCEPTS</a></cite>], which will
                    have been obtained according to the section on <a href="#s_curieprocessing">CURIE

                      and IRI Processing</a>.</p>
                </li>
                <li id="C7" about="#C7" resource="http://www.w3.org/2010/02/rdfa/meetings/2010-06-17#resolution_2" rel="bibo:affirmedBy">
                  <em>otherwise</em>, as an <a class="tref" title="xml-literals" href="#T-xml-literals">XML
                    literal</a> if <a class="aref" href="#A-datatype" title="datatype">@datatype</a> is present and is
                  set to <code>XMLLiteral</code> in the vocabulary <code>http://www.w3.org/1999/02/22-rdf-syntax-ns#</code>.
                  <p>The value of the <a class="tref" title="xml-literals" href="#T-xml-literals">XML literal</a>
                    is a string created by serializing to text, all nodes that
                    are descendants of the <a class="tref" title="current-element" href="#T-current-element">current element</a>, i.e.,
                    not including the element itself, and giving it a datatype
                    of <code>XMLLiteral</code> in the vocabulary <code>http://www.w3.org/1999/02/22-rdf-syntax-ns#</code>.
                    The format of the resulting serialized content is as defined
                    in Exclusive XML Canonicalization Version [<cite><a class="bibref" rel="biblioentry" href="#bib-XML-EXC-C14N">XML-EXC-C14N</a></cite>].</p>
                  <p class="note" id="C19" about="#C19" resource="http://www.w3.org/2010/02/rdfa/meetings/2011-01-13#ISSUE__2d_60__3a__XMLLiteral_context_preservation" rel="bibo:affirmedBy">
                    In order to maintain maximum portability of this literal,
                    any children of the current node that are elements <em class="rfc2119" title="must">must</em> have
                    the current XML namespace declarations (if any) declared on
                    the serialized element. Since the child element node could
                    also declare new XML namespaces, the RDFa Processor <em class="rfc2119" title="must">must</em> be
                    careful to merge these together when generating the
                    serialized element definition. For avoidance of doubt, any
                    re-declarations on the child node <em class="rfc2119" title="must">must</em> take precedence over
                    declarations that were active on the current node. </p>
                </li>
                <li id="GK6" about="#GK6" resource="http://www.w3.org/2010/02/rdfa/meetings/2011-11-10#resolution_2" rel="bibo:affirmedBy">
                  <em>otherwise</em>, as an <a class="tref" title="plain-literal" href="#T-plain-literal">plain literal</a> using
                  the value of <a class="aref" href="#A-content" title="content">@content</a> if <a class="aref" href="#A-content" title="content">@content</a> is
                  present.</li>
                <li id="GK7" about="#GK7" resource="http://www.w3.org/2010/02/rdfa/meetings/2011-11-10#resolution_2" rel="bibo:affirmedBy">
                  <em>otherwise</em>, as an <a class="tref" title="iri-reference" href="#T-iri-reference">IRI Reference</a>,
                  obtained via the <a href="#s_curieprocessing">CURIE and IRI
                    Processing</a> of the first value of the <a class="aref" href="#A-resource" title="resource">@resource</a>,
                  <a class="aref" href="#A-href" title="href">@href</a>, or <a class="aref" href="#A-src" title="src">@src</a>, if present, <em>and</em>
                  the <a class="aref" href="#A-rel" title="rel">@rel</a>, <a class="aref" href="#A-rev" title="rev">@rev</a>, or <a class="aref" href="#A-content" title="content">@content</a>
                  attributes are <em>not</em> present.</li>
                <li id="GK8" about="#GK8" resource="http://www.w3.org/2010/02/rdfa/meetings/2011-11-10#resolution_2" rel="bibo:affirmedBy">
                  <em>otherwise</em>, if <a class="aref" href="#A-typeof" title="typeof">@typeof</a> is present and <a class="aref" href="#A-about" title="about">@about</a>
                  is not, the value of <a class="tref" title="typed-resource" href="#T-typed-resource">typed resource</a>. </li>
                <li id="C8" about="#C8" resource="http://www.w3.org/2010/02/rdfa/meetings/2010-05-13#resolution_2" rel="bibo:affirmedBy">
                  <em>otherwise</em> as a <a class="tref" title="plain-literal" href="#T-plain-literal">plain literal</a>.
                  <p>Additionally, if there is a value for <dfn title="current-language" id="T-current-language">current
                      language</dfn> then the value of the <a class="tref" title="plain-literal" href="#T-plain-literal">plain literal</a>
                    should include this language information, as described in
                    [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-CONCEPTS">RDF-CONCEPTS</a></cite>]. The actual literal is either the value of
                    <a class="aref" href="#A-content" title="content">@content</a> (if present) <em>or</em> a string
                    created by concatenating the text content of each of the
                    descendant elements of the <a class="tref" title="current-element" href="#T-current-element">current element</a> in
                    document order.</p>
                </li>
              </ul>
              <p>The <a class="tref" title="current-property-value" href="#T-current-property-value">current property value</a> is then used with each
                predicate as follows:</p>
              <ul>
                <li>If the element also includes the <a class="aref" href="#A-inlist" title="inlist">@inlist</a>
                  attribute, the <a class="tref" title="current-property-value" href="#T-current-property-value">current property value</a> is added
                  to the <a class="tref" title="local-list-mapping" href="#T-local-list-mapping">local list mapping</a> as follows:
                  <ul>
                    <li>if the <a class="tref" title="local-list-mapping" href="#T-local-list-mapping">local list mapping</a> does not contain
                      a list associated with the predicate IRI, instantiate a
                      new list and add to local list mappings</li>
                    <li>add the <a class="tref" title="current-property-value" href="#T-current-property-value">current property value</a> to the list
                      associated with the predicate IRI in the <a class="tref" title="local-list-mapping" href="#T-local-list-mapping">local list
                        mapping</a></li>
                  </ul>
                </li>
                <li>Otherwise the <a class="tref" title="current-property-value" href="#T-current-property-value">current property value</a> is used
                  to generate a triple as follows:
                  <dl>
                    <dt>subject</dt>
                    <dd><a class="tref" title="new-subject" href="#T-new-subject">new subject</a></dd>
                    <dt>predicate</dt>
                    <dd>full IRI</dd>
                    <dt>object</dt>
                    <dd><a class="tref" title="current-property-value" href="#T-current-property-value">current property value</a></dd>
                  </dl>
                </li>
              </ul>
            </div>
            
<!--  <p>Once the triple has been created, if the <tdef>datatype</tdef> of the <tref>current property value</tref> is <code>rdf:XMLLiteral</code>,
          then the <tref>recurse</tref> flag is set to          <code>false</code>.</p>  -->

          </li>
          <li id="PS-complete-triples"> If the <a class="tref" title="skip-element" href="#T-skip-element">skip element</a> flag
            is 'false', <em>and</em> <a class="tref" title="new-subject" href="#T-new-subject">new subject</a> was set to a
            non-null value, then any <a class="tref" title="incomplete-triple" href="#T-incomplete-triple">incomplete triple</a>s <em>within

              the current context</em> should be completed:
            <div class="explanation"> The <a class="tref" title="list-of-incomplete-triples" href="#T-list-of-incomplete-triples">list of incomplete triples</a>
              from the current <a class="tref" title="evaluation-context" href="#T-evaluation-context">evaluation context</a> (<em>not</em>
              the <a class="tref" title="local-list-of-incomplete-triples" href="#T-local-list-of-incomplete-triples">local list of incomplete triples</a>) will contain
              zero or more predicate IRIs. This list is iterated and is and each
              of the predicates is used with <a class="tref" title="parent-subject" href="#T-parent-subject">parent subject</a> and <a class="tref" title="new-subject" href="#T-new-subject">new

                subject</a> to generate a triple or add a new element to the
              <a class="tref" title="local-list-mapping" href="#T-local-list-mapping">local list mapping</a>. Note that at each level there are
              <em>two</em> lists of <a class="tref" title="incomplete-triple" href="#T-incomplete-triple">incomplete triple</a>s; one for
              the current processing level (which is passed to each child
              element in the previous step), and one that was received as part
              of the <a class="tref" title="evaluation-context" href="#T-evaluation-context">evaluation context</a>. It is the latter that is
              used in processing during this step. </div>
            <div class="explanation"> Note that each <a class="tref" title="incomplete-triple" href="#T-incomplete-triple">incomplete triple</a>
              has a <dfn title="direction" id="T-direction">direction</dfn> value that it used to determine what
              will become the subject, and what will become the object, of each
              generated triple:
              <ul>
                <li>If <a class="tref" title="direction" href="#T-direction">direction</a> is 'none', the <a class="tref" title="new-subject" href="#T-new-subject">new subject</a>
                  is added to the list from the iterated <a class="tref" title="incomplete-triple" href="#T-incomplete-triple">incomplete
                    triple</a>. </li>
                <li> If <a class="tref" title="direction" href="#T-direction">direction</a> is 'forward' then the following
                  triple is generated:
                  <dl>
                    <dt>subject</dt>
                    <dd><a class="tref" title="parent-subject" href="#T-parent-subject">parent subject</a></dd>
                    <dt>predicate</dt>
                    <dd>the predicate from the iterated <a class="tref" title="incomplete-triple" href="#T-incomplete-triple">incomplete triple</a></dd>
                    <dt>object</dt>
                    <dd><a class="tref" title="new-subject" href="#T-new-subject">new subject</a></dd>
                  </dl>
                </li>
                <li> If <a class="tref" title="direction" href="#T-direction">direction</a> is neither 'forward' nor 'none'
                  then this is the triple generated:
                  <dl>
                    <dt>subject</dt>
                    <dd><a class="tref" title="new-subject" href="#T-new-subject">new subject</a></dd>
                    <dt>predicate</dt>
                    <dd>the predicate from the iterated <a class="tref" title="incomplete-triple" href="#T-incomplete-triple">incomplete triple</a></dd>
                    <dt>object</dt>
                    <dd><a class="tref" title="parent-subject" href="#T-parent-subject">parent subject</a></dd>
                  </dl>
                </li>
              </ul>
            </div>
          </li>
          <li id="PS-recurse"> Next, all elements that are children of the <a class="tref" title="current-element" href="#T-current-element">current

              element</a> are processed using the rules described here, using
            a new <a class="tref" title="evaluation-context" href="#T-evaluation-context">evaluation context</a>, initialized as follows:
            <ul>
              <li> If the <a class="tref" title="skip-element" href="#T-skip-element">skip element</a> flag is 'true' then the new
                <a class="tref" title="evaluation-context" href="#T-evaluation-context">evaluation context</a> is a copy of the current context
                that was passed in to this level of processing, with the <a class="tref" title="language" href="#T-language">language</a>
                and <a class="tref" title="list-of-iri-mappings" href="#T-list-of-iri-mappings">list of IRI mappings</a> values replaced with the
                local values; </li>
              <li> Otherwise, the values are:
                <ul>
                  <li>the <a class="tref" title="base" href="#T-base">base</a> is set to the <a class="tref" title="base" href="#T-base">base</a>
                    value of the current <a class="tref" title="evaluation-context" href="#T-evaluation-context">evaluation context</a>;</li>
                  <li>the <a class="tref" title="parent-subject" href="#T-parent-subject">parent subject</a> is set to the value of <a class="tref" title="new-subject" href="#T-new-subject">new

                      subject</a>, if non-null, <em>or</em> the value of the
                    <a class="tref" title="parent-subject" href="#T-parent-subject">parent subject</a> of the current <a class="tref" title="evaluation-context" href="#T-evaluation-context">evaluation
                      context</a>;</li>
                  <li>the <a class="tref" title="parent-object" href="#T-parent-object">parent object</a> is set to value of <a class="tref" title="current-object-resource" href="#T-current-object-resource">current

                      object resource</a>, if non-null, <em>or</em> the
                    value of <a class="tref" title="new-subject" href="#T-new-subject">new subject</a>, if non-null, <em>or</em>
                    the value of the <a class="tref" title="parent-subject" href="#T-parent-subject">parent subject</a> of the current
                    <a class="tref" title="evaluation-context" href="#T-evaluation-context">evaluation context</a>;</li>
                  <li>the <a class="tref" title="list-of-iri-mappings" href="#T-list-of-iri-mappings">list of IRI mappings</a> is set to the <a class="tref" title="local-list-of-iri-mappings" href="#T-local-list-of-iri-mappings">local

                      list of IRI mappings</a>;</li>
                  <li>the <a class="tref" title="list-of-incomplete-triples" href="#T-list-of-incomplete-triples">list of incomplete triples</a> is set to the
                    <a class="tref" title="local-list-of-incomplete-triples" href="#T-local-list-of-incomplete-triples">local list of incomplete triples</a>;</li>
                  <li>the <a class="tref" title="list-mapping" href="#T-list-mapping">list mapping</a> is set to the <a class="tref" title="local-list-mapping" href="#T-local-list-mapping">local
                      list mapping</a>;</li>
                  <li><a class="tref" title="language" href="#T-language">language</a> is set to the value of <a class="tref" title="current-language" href="#T-current-language">current

                      language</a>.</li>
                  
<!--  <li>the <tref>term mappings</tref> is set to the value of the
                <tref>local term mappings</tref>.</li>  -->

                  <li>the <a class="tref" title="default-vocabulary" href="#T-default-vocabulary">default vocabulary</a> is set to the value
                    of the <a class="tref" title="local-default-vocabulary" href="#T-local-default-vocabulary">local default vocabulary</a>.</li>
                </ul>
              </li>
            </ul>
          </li>
          <li id="PS-Lists"> Once all the child elements have been traversed,
            list triples are generated, if necessary.
            <div class="explanation"> For each IRI in the <a class="tref" title="local-list-mapping" href="#T-local-list-mapping">local list
                mapping</a>, if the equivalent list does not exist in the <a class="tref" title="evaluation-context" href="#T-evaluation-context">evaluation

                context</a>, indicating that the list was originally defined
              on the current element, use the list as follows:
              <ul>
                <li>Create a new ‘bnode’ array containing newly created <a class="tref" title="bnode" href="#T-bnode">bnode</a>s,

                  one for each element in the list</li>
                <li>For each pair of <a class="tref" title="bnode" href="#T-bnode">bnode</a> and IRI from the list
                  the following triple is generated:
                  <dl>
                    <dt>subject</dt>
                    <dd><a class="tref" title="bnode" href="#T-bnode">bnode</a></dd>
                    <dt>predicate</dt>
                    <dd>http://www.w3.org/1999/02/22-rdf-syntax-ns#first</dd>
                    <dt>object</dt>
                    <dd>full IRI</dd>
                  </dl>
                </li>
                <li>For each element in the ‘bnode’ array the following triple
                  is generated:
                  <dl>
                    <dt>subject</dt>
                    <dd><a class="tref" title="bnode" href="#T-bnode">bnode</a></dd>
                    <dt>predicate</dt>
                    <dd>http://www.w3.org/1999/02/22-rdf-syntax-ns#rest</dd>
                    <dt>object</dt>
                    <dd>next element in the ‘bnode’ array or, if that does not
                      exist, http://www.w3.org/1999/02/22-rdf-syntax-ns#nil</dd>
                  </dl>
                </li>
                <li>A single additional triple is generated:
                  <dl>
                    <dt>subject</dt>
                    <dd><a class="tref" title="current-subject" href="#T-current-subject">current subject</a></dd>
                    <dt>predicate</dt>
                    <dd>full IRI of the <a class="tref" title="local-list-mapping" href="#T-local-list-mapping">local list mapping</a>
                      associated with this list</dd>
                    <dt>object</dt>
                    <dd>first element of the ‘bnode’ array</dd>
                  </dl>
                </li>
              </ul>
            </div>
          </li>
        </ol>
      </div>
      <div id="processor-status" typeof="bibo:Chapter" about="#processor-status" class="section">
        <h3><span class="secno">7.6 </span>Processor Status</h3>
        <p> The processing rules covered in the previous section are designed to
          extract as many triples as possible from a document. The RDFa
          Processor is designed to continue processing, even in the event of
          errors. For example, failing to resolve a prefix mapping or <a class="tref" title="term" href="#T-term">term</a>
          would result in the RDFa Processor skipping the generation of a triple
          and continuing with document processing. There are cases where knowing
          each RDFa Processor warning or error would be beneficial to authors.
          The <a class="tref" title="processor-graph" href="#T-processor-graph">processor graph</a> is designed as a possible mechanism
          to capture all informational, warning, and error messages as triples
          from the RDFa Processor. These status triples may be retrieved and
          used to aid RDFa authoring or automated error detection. </p>
        <p id="C15" about="#C15" rel="bibo:affirmedBy" resource="http://www.w3.org/2010/02/rdfa/meetings/2010-07-15#resolution_1">
          If an RDFa Processor supports the generation of a processor graph,
          then it <em class="rfc2119" title="must">must</em> generate a set of triples when the following processing
          issues occur: </p>
        <ul>
          <li>An rdfa:Error <em class="rfc2119" title="must">must</em> be generated when the document fails to be
            fully processed as a result of non-conformant host language markup.</li>
          <li>A rdfa:Warning <em class="rfc2119" title="must">must</em> be generated when a CURIE prefix fails to be
            resolved.</li>
          <li>A rdfa:Warning <em class="rfc2119" title="must">must</em> be generated when a Term fails to be resolved.</li>
        </ul>
        <p> Other implementation-specific rdfa:Info, rdfa:Warning, or rdfa:Error
          triples <em class="rfc2119" title="may">may</em> be generated by the RDFa Processor. </p>
        <div id="accessing-the-processor-graph" typeof="bibo:Chapter" about="#accessing-the-processor-graph" class="section">
          <h4><span class="secno">7.6.1 </span>Accessing the Processor Graph</h4>
          <p> Accessing the <a class="tref" title="processor-graph" href="#T-processor-graph">processor graph</a> may be accomplished in
            a variety of ways and is dependent on the type of RDFa Processor and
            access method that the developer is utilizing. </p>
          <p> SAX-based processors or processors that utilize function or method
            callbacks to report the generation of triples are classified as <dfn title="event-based-rdfa-processor" id="T-event-based-rdfa-processor">event-based

              RDFa Processor</dfn>s. For Event-based RDFa Processors, the
            software <em class="rfc2119" title="must">must</em> allow the developer to register a function or callback
            that is called when a triple is generated for the <a class="tref" title="processor-graph" href="#T-processor-graph">processor
              graph</a>. The callback <em class="rfc2119" title="may">may</em> be the same as the one that is used
            for the <a class="tref" title="output-graph" href="#T-output-graph">output graph</a> as long as it can be determined
            if a generated triple belongs in the <a class="tref" title="processor-graph" href="#T-processor-graph">processor graph</a>
            or the <a class="tref" title="output-graph" href="#T-output-graph">output graph</a>. </p>
          <p> A <dfn title="whole-graph-rdfa-processor" id="T-whole-graph-rdfa-processor">whole-graph RDFa Processor</dfn> is defined as any RDFa
            Processor that processes the entire document and only allows
            developer access to the triples after processing has completed. RDFa
            Processors that typically fall into this category express their
            output via a single call using RDF/XML, N3, TURTLE, or N-Triples
            notation. For whole-graph RDFa Processors, the software <em class="rfc2119" title="must">must</em> allow
            the developer to specify if they would like to retrieve the <a class="tref" title="output-graph" href="#T-output-graph">output

              graph</a>, the <a class="tref" title="processor-graph" href="#T-processor-graph">processor graph</a>, or both graphs as
            a single, combined graph from the RDFa Processor. <span id="whole-graph-output-graph-preference" about="#whole-graph-output-graph-preference" rel="bibo:affirmedBy" resource="http://www.w3.org/2010/02/rdfa/meetings/2010-07-01#resolution_1">
              If the graph preference is not specified, the <a class="tref" title="output-graph" href="#T-output-graph">output graph</a>
              <em class="rfc2119" title="must">must</em> be returned. </span> </p>
          <p> An <dfn title="web-service-rdfa-processor" id="T-web-service-rdfa-processor">web service RDFa Processor</dfn> is defined as any RDFa
            Processor that is capable of processing a document by performing an
            HTTP GET, POST or similar action on an RDFa Processor IRI. For this
            class of RDFa Processor, the software <em class="rfc2119" title="must">must</em> allow the caller to
            specify if they would like to retrieve the <a class="tref" title="output-graph" href="#T-output-graph">output graph</a>,
            the <a class="tref" title="processor-graph" href="#T-processor-graph">processor graph</a>, or both graphs as a single,
            combined graph from the web service. The <code>rdfagraph</code>
            query parameter <em class="rfc2119" title="must">must</em> be used to specify the value. The allowable
            values are <code>output</code>, <code>processor</code> or both
            values, in any order, separated by a comma character. <span id="web-service-output-graph-preference" about="#web-service-output-graph-preference" rel="bibo:affirmedBy" resource="http://www.w3.org/2010/02/rdfa/meetings/2010-07-01#resolution_1">
              If the graph preference is not specified, the <a class="tref" title="output-graph" href="#T-output-graph">output graph</a>
              <em class="rfc2119" title="must">must</em> be returned. </span> </p>
        </div>
        <div id="processor-graph-terms" typeof="bibo:Chapter" about="#processor-graph-terms" class="section">
          <h4><span class="secno">7.6.2 </span>Processor Graph Terms</h4>
          <p> To ensure interoperability, a core hierarchy of classes is defined
            for the content of the processor graph. Separate errors or warnings
            are resources (typically blank nodes) of a specific type, with
            additional properties giving more details on the error condition or
            the warning. This specification defines only the top level classes
            and the ones referring to the error and warning conditions defined <a href="#processor-status">explicitly</a>
            by this document. Other, implementation-specific subclasses may be
            defined by the RDFa Processor.</p>
          <p>The top level classes are <code>rdfa:Error</code>, <code>rdfa:Warning</code>,
            and <code>rdfa:Info</code>, defined as part of the <a href="#processor-graph-reporting">RDFa

              Vocabulary</a>. Furthermore, a single property is defined on those
            classes, namely <code>rdfa:context</code>, that provides an extra
            context for the error, e.g., http response, an XPath information, or
            simply the IRI to the RDFa resource. Usage of this property is
            optional, and more than one triple can be used with this predicate
            on the same subject. Finally, error and warning instances <em class="rfc2119" title="should">should</em> use
            the <code>dc:description</code> and <code>dc:date</code>
            properties. <code>dc:description</code> should provide a short,
            human readable but implementation dependent description of the
            error. <code>dc:date</code> should give the time when the error was
            found and it is advised to be as precise as possible to allow the
            detection of, for example, possible network errors. </p>
          <p>The example below shows the triples that should be minimally
            present in the processor graph as a result of an error (the content
            of the literal for the <code>dc:description</code> predicate is
            implementation dependent): </p>
          <pre class="example">@prefix rdfa:    &lt;http://www.w3.org/ns/rdfa#&gt; .
@prefix xsd:     &lt;http://www.w3.org/2001/XMLSchema#&gt; .
@prefix dc: &lt;http://purl.org/dc/terms/&gt; .
[] a rdfa:DocumentError ;
   dc:description &quot;The document could not be parsed due to parsing errors&quot; ;
   dc:date &quot;2010-06-30T13:40:23&quot;^^xsd:dateTime .</pre>
          <p>A slightly more elaborate example makes use of the <code>rdfa:context</code>
            property to provide further information, using external vocabularies
            to represent HTTP headers or XPointer information (note that a
            processor may not have these information in all cases, i.e., these <code>rdfa:context</code>
            information are not required):</p>
          <pre class="example">@prefix rdfa:    &lt;http://www.w3.org/ns/rdfa#&gt; .
@prefix xsd:     &lt;http://www.w3.org/2001/XMLSchema#&gt; .
@prefix dc: &lt;http://purl.org/dc/terms/&gt; .
@prefix ptr:     &lt;http://www.w3.org/2009/pointers#&gt; .
@prefix http:    &lt;http://www.w3.org/2006/http#&gt; .
 
[] a rdfa:DocumentError ;
   dc:description &quot;The document could not be parsed due to parsing errors&quot; ;
   dc:date &quot;2010-06-30T13:40:23&quot;^^xsd:dateTime ;
   rdfa:context &lt;http://www.example.org/doc&gt; ;
   rdfa:context [
      a ptr:Pointer ;
      # detailed xpointer/xpath information provided here to locate the 
      # error
   ] ;
   rdfa:context [
      a http:Response ;
      http:responseCode &lt;http://www.w3.org/2006/http#404&gt;
      # Get the HTTP response headers on the request for the source file.
   ].</pre> </div>
      </div>
      <div id="vocabulary-expansion" typeof="bibo:Chapter" about="#vocabulary-expansion" class="section">
        <h3><span class="secno">7.7 </span>Vocabulary Expansion</h3>
        <p> Processors <em class="rfc2119" title="may">may</em> perform limited RDFS entailment rules to perform
          vocabulary expansion, as described in <a href="#s_vocab_expansion">RDFa

            Vocabulary Expansion</a>. </p>
      </div>
    </div>
    <div class="informative section" id="s_rdfaindetail" typeof="bibo:Chapter" about="#s_rdfaindetail">
      
<!-- OddPage -->
<h2><span class="secno">8. </span>RDFa Processing in detail</h2><p><em>This section is non-normative.</em></p>
      <p> This section provides an in-depth examination of the processing steps
        described in the previous section. It also includes examples which may
        help clarify some of the steps involved. </p>
      <p> The key to processing is that a triple is generated whenever a
        predicate/object combination is detected. The actual triple generated
        will include a subject that may have been set previously, so this is
        tracked in the current <a class="tref" title="evaluation-context" href="#T-evaluation-context">evaluation context</a> and is called
        the <a class="tref" title="parent-subject" href="#T-parent-subject">parent subject</a>. Since the subject will default to the
        current document if it hasn't been set explicitly, then a
        predicate/object combination is always enough to generate one or more
        triples. </p>
      <p> The attributes for setting a predicate are <a class="aref" href="#A-rel" title="rel">@rel</a>, <a class="aref" href="#A-rev" title="rev">@rev</a>
        and <a class="aref" href="#A-property" title="property">@property</a>, whilst the attributes for setting an object
        are <a class="aref" href="#A-resource" title="resource">@resource</a>, <a class="aref" href="#A-href" title="href">@href</a>, <a class="aref" href="#A-content" title="content">@content</a>,
        and <a class="aref" href="#A-src" title="src">@src</a>. <a class="aref" href="#A-typeof" title="typeof">@typeof</a> is unique in that it sets <em>both</em>
        a predicate and an object at the same time (and also a subject when it
        appears in the absence of other attributes that would set a subject).
        Inline content might also set an object, if <a class="aref" href="#A-content" title="content">@content</a> is not
        present, but <a class="aref" href="#A-property" title="property">@property</a> is present. </p>
      <p class="note"> There are many examples in this section. The examples are
        all written using XHTML+RDFa. However, the explanations are relevant
        regardless of the Host Language.</p>
      <div id="changing-the-evaluation-context" typeof="bibo:Chapter" about="#changing-the-evaluation-context" class="section">
        <h3><span class="secno">8.1 </span>Changing the evaluation context</h3>
        <div id="setting-the-current-subject" typeof="bibo:Chapter" about="#setting-the-current-subject" class="section">
          <h4><span class="secno">8.1.1 </span>Setting the current subject</h4>
          <p>When triples are created they will always be in relation to a
            subject resource which is provided either by <a class="tref" title="new-subject" href="#T-new-subject">new subject</a>
            (if there are rules on the current element that have set a subject)
            or <a class="tref" title="parent-subject" href="#T-parent-subject">parent subject</a>, as passed in via the <a class="tref" title="evaluation-context" href="#T-evaluation-context">evaluation

              context</a>. This section looks at the specific ways in which
            these values are set. Note that it doesn't matter how the subject is
            set, so in this section we use the idea of the <dfn title="current-subject" id="T-current-subject">current
              subject</dfn> which may be <em>either</em> <a class="tref" title="new-subject" href="#T-new-subject">new subject</a>
            or <a class="tref" title="parent-subject" href="#T-parent-subject">parent subject</a>.</p>
          <div id="the-current-document" typeof="bibo:Chapter" about="#the-current-document" class="section">
            <h5><span class="secno">8.1.1.1 </span>The current document</h5>
            <p>When parsing begins, the <a class="tref" title="current-subject" href="#T-current-subject">current subject</a> will be
              the IRI of the document being parsed, or a value as set by a Host
              Language-provided mechanism (e.g., the <code>base</code> element
              in (X)HTML). This means that by default any metadata found in the
              document will concern the document itself:</p>
            <pre class="example">&lt;html&gt;
  &lt;head&gt;
    &lt;title&gt;Jo's Friends and Family Blog&lt;/title&gt;
    <span class="hilite">&lt;link rel=&quot;foaf:primaryTopic&quot; href=&quot;#bbq&quot; /&gt;</span>
    <span class="hilite">&lt;meta property=&quot;dc:creator&quot; content=&quot;Jo&quot; /&gt;</span>
  &lt;/head&gt;
  &lt;body&gt;
    ...
  &lt;/body&gt;
&lt;/html&gt;</pre>
            <p>This would generate the following triples:</p>
            <pre class="example">&lt;&gt; foaf:primaryTopic &lt;#bbq&gt; .
&lt;&gt; dc:creator &quot;Jo&quot; .</pre>
            <p>It is possible for the data to appear elsewhere in the document:</p>
            <pre class="example">&lt;html&gt;
  &lt;head&gt;
    &lt;title&gt;Jo's Blog&lt;/title&gt;
  &lt;/head&gt;
  &lt;body&gt;
    &lt;h1&gt;<span class="hilite">&lt;span property=&quot;dc:creator&quot;&gt;Jo&lt;/span&gt;</span>'s blog&lt;/h1&gt;
    &lt;p&gt;
      Welcome to my blog.
    &lt;/p&gt;
  &lt;/body&gt;
&lt;/html&gt;</pre>
            <p>which would still generate the triple:</p>
            <pre class="example">&lt;&gt; dc:creator &quot;Jo&quot; .</pre>
            <p>In (X)HTML the value of <code>base</code> may change the initial
              value of <a class="tref" title="current-subject" href="#T-current-subject">current subject</a>:</p>
            <pre class="example">&lt;html&gt;
  &lt;head&gt;
    <span class="hilite">&lt;base href=&quot;http://www.example.org/jo/blog&quot; /&gt;</span>
    &lt;title&gt;Jo's Friends and Family Blog&lt;/title&gt;
    &lt;link rel=&quot;foaf:primaryTopic&quot; href=&quot;#bbq&quot; /&gt;
    &lt;meta property=&quot;dc:creator&quot; content=&quot;Jo&quot; /&gt;
  &lt;/head&gt;
  &lt;body&gt;
    ...
  &lt;/body&gt;
&lt;/html&gt;</pre>
            <p>An RDFa Processor should now generate the following triples,
              regardless of the IRI from which the document is served:</p>
            <pre class="example">&lt;http://www.example.org/jo/blog&gt; foaf:primaryTopic &lt;#bbq&gt; .
&lt;http://www.example.org/jo/blog&gt; dc:creator &quot;Jo&quot; .</pre> </div>
          <div id="using--about" typeof="bibo:Chapter" about="#using--about" class="section">
            <h5><span class="secno">8.1.1.2 </span>Using <a class="aref" href="#A-about" title="about">@about</a></h5>
            <p>As processing progresses, any <a class="aref" href="#A-about" title="about">@about</a> attributes will
              change the <a class="tref" title="current-subject" href="#T-current-subject">current subject</a>. The value of <a class="aref" href="#A-about" title="about">@about</a>
              is an IRI or a CURIE. If it is a relative IRI then it needs to be
              resolved against the current <a class="tref" title="base" href="#T-base">base</a> value. To
              illustrate how this affects the statements, note in this markup
              how the properties inside the (X)HTML <code>body</code> element
              become part of a new calendar event object, rather than referring
              to the document as they do in the head of the document: </p>
            <pre class="example">&lt;html prefix=&quot;cal: http://www.w3.org/2002/12/cal/ical#&quot;&gt;
  &lt;head&gt;
    &lt;title&gt;Jo's Friends and Family Blog&lt;/title&gt;
    &lt;link rel=&quot;foaf:primaryTopic&quot; href=&quot;#bbq&quot; /&gt;
    &lt;meta property=&quot;dc:creator&quot; content=&quot;Jo&quot; /&gt;
  &lt;/head&gt;
  &lt;body&gt;
    &lt;p <span class="hilite">about=&quot;#bbq&quot;</span> <span class="hilite">typeof=&quot;cal:Vevent&quot;</span>&gt;
      I'm holding
      &lt;span <span class="hilite">property=&quot;cal:summary&quot;</span>&gt;
        one last summer barbecue
      &lt;/span&gt;,
      on
      &lt;span <span class="hilite">property=&quot;cal:dtstart&quot;</span> content=&quot;2015-09-16T16:00:00-05:00&quot; 
            datatype=&quot;xsd:dateTime&quot;&gt;
        September 16th at 4pm
      &lt;/span&gt;.
    &lt;/p&gt;
  &lt;/body&gt;
&lt;/html&gt;</pre>
            <p>With this markup an RDFa Processor will generate the following
              triples:</p>
            <pre class="example">&lt;&gt; foaf:primaryTopic &lt;#bbq&gt; .
&lt;&gt; dc:creator &quot;Jo&quot; .
<span class="hilite">&lt;#bbq&gt; rdf:type cal:Vevent .</span>
<span class="hilite">&lt;#bbq&gt; cal:summary &quot;one last summer barbecue&quot; .</span>
<span class="hilite">&lt;#bbq&gt; cal:dtstart &quot;2015-09-16T16:00:00-05:00&quot;^^xsd:dateTime .</span></pre>
            <p>Other kinds of resources can be used to set the <a class="tref" title="current-subject" href="#T-current-subject">current
                subject</a>, not just references to web-pages. Although not
              advised, email addresses might be used to represent a person:</p>
            <pre class="example">John knows
&lt;a <span class="hilite">about=&quot;mailto:john@example.org&quot;</span>
  rel=&quot;foaf:knows&quot; href=&quot;mailto:sue@example.org&quot;&gt;Sue&lt;/a&gt;.

Sue knows
&lt;a <span class="hilite">about=&quot;mailto:sue@example.org&quot;</span>
  rel=&quot;foaf:knows&quot; href=&quot;mailto:jim@example.org&quot;&gt;Jim&lt;/a&gt;.</pre>
            <p>This should generate the following triples:</p>
            <pre class="example">&lt;mailto:john@example.org&gt; foaf:knows &lt;mailto:sue@example.org&gt; .
&lt;mailto:sue@example.org&gt; foaf:knows &lt;mailto:jim@example.org&gt; .</pre>
            <p>Similarly, authors may make statements about images:</p>
            <pre class="example">&lt;div <span class="hilite">about=&quot;photo1.jpg&quot;</span>&gt;
  this photo was taken by
  &lt;span property=&quot;dc:creator&quot;&gt;Mark Birbeck&lt;/span&gt;
&lt;/div&gt;</pre>
            <p>which should generate the following triples:</p>
            <pre class="example">&lt;photo1.jpg&gt; dc:creator &quot;Mark Birbeck&quot; .</pre> </div>
          <div id="typing-resources-with--typeof" typeof="bibo:Chapter" about="#typing-resources-with--typeof" class="section">
            <h5><span class="secno">8.1.1.3 </span>Typing resources with <a class="aref" href="#A-typeof" title="typeof">@typeof</a></h5>
            <p><a class="aref" href="#A-typeof" title="typeof">@typeof</a> defines typing triples. <a class="aref" href="#A-typeof" title="typeof">@typeof</a>
              works differently to other ways of setting a predicate since the
              predicate is always <code>rdf:type</code>, which means that the
              processor only requires one attribute, the value of the type. The
              question is: which resource gets these typing information?</p>
            <p>If the element has an <a class="aref" href="#A-about" title="about">@about</a>, which creates a new
              context for statements, the typing relationships are defined on
              that resource. For example, the following:</p>
            <pre class="example">&lt;div <span class="hilite"> about=&quot;http://dbpedia.org/resource/Albert_Einstein&quot; typeof=&quot;foaf:Person&quot;</span>&gt;
  &lt;span property=&quot;foaf:name&quot;&gt;Albert Einstein&lt;/span&gt;
  &lt;span property=&quot;foaf:givenName&quot;&gt;Albert&lt;/span&gt;
&lt;/div&gt;</pre>
            <p>also creates the triple:</p>
            <pre class="example">&lt;http://dbpedia.org/resource/Albert_Einstein&gt; rdf:type foaf:Person .</pre>
            <p>The <a class="aref" href="#A-about" title="about">@about</a> attribute is the main source for typing;
              if it is present on an element, it determines the effect of <a class="aref" href="#A-typeof" title="typeof">@typeof</a>
              with the highest priority. If <a class="aref" href="#A-about" title="about">@about</a> is <em>not</em>
              present, but the element is used only to define possible subject
              resources via, e.g., <a class="aref" href="#A-resource" title="resource">@resource</a> (i.e., there is <em>no</em>
              <a class="aref" href="#A-rel" title="rel">@rel</a>, <a class="aref" href="#A-rev" title="rev">@rev</a>, or <a class="aref" href="#A-property" title="property">@property</a>
              present), then that resource is used for the typed resource, just
              like <a class="aref" href="#A-about" title="about">@about</a>.</p>
            <p>If an <a class="aref" href="#A-rel" title="rel">@rel</a> is present (and still no <a class="aref" href="#A-about" title="about">@about</a>)
              then the explicit object of the triples defined by <a class="aref" href="#A-rel" title="rel">@rel</a>
              is typed. For example, in the case of:</p>
            <pre class="example">&lt;div about=&quot;http://dbpedia.org/resource/Albert_Einstein&quot;&gt;
  &lt;div rel=&quot;dbp:birthPlace&quot; 
      <span class="hilite">resource=&quot;http://dbpedia.org/resource/German_Empire&quot;</span>
      <span class="hilite">typeof=&quot;http://schema.org/Country&quot;</span>&gt;
  &lt;/div&gt;
&lt;/div&gt;</pre>
            <p>the generated triples also include:</p>
            <pre class="example">&lt;http://dbpedia.org/resource/German_Empire&gt; rdf:type &lt;http://schema.org/Country&gt; .</pre>
            <p>Finally, <a class="aref" href="#A-typeof" title="typeof">@typeof</a> also has the additional feature of
              creating a new context for statements, <em>in case no other
                attributes define any</em>. This involves generating a new <a class="tref" title="bnode" href="#T-bnode">bnode</a>
              (see below for more about bnodes). For example, an author may wish
              to create markup for a person using the FOAF vocabulary, but
              without having a clear identifier for the item: </p>
            <pre class="example">&lt;div <span class="hilite">typeof=&quot;foaf:Person&quot;</span>&gt;
  &lt;span property=&quot;foaf:name&quot;&gt;Albert Einstein&lt;/span&gt;
  &lt;span property=&quot;foaf:givenName&quot;&gt;Albert&lt;/span&gt;
&lt;/div&gt;</pre>
            <p> This markup would cause a <a class="tref" title="bnode" href="#T-bnode">bnode</a> to be created
              which has a 'type' of <code>foaf:Person</code>, as well as name
              and given name properties: </p>
            <pre class="example">_:a rdf:type foaf:Person .
_:a foaf:name &quot;Albert Einstein&quot; .
_:a foaf:givenName &quot;Albert&quot; .</pre>
            <p>This usage of <a class="aref" href="#A-typeof" title="typeof">@typeof</a> is a shorthand for: </p>
            <pre class="example">&lt;div <span class="hilite">about=&quot;_:a&quot; typeof=&quot;foaf:Person&quot;</span>&gt;
  &lt;span property=&quot;foaf:name&quot;&gt;Albert Einstein&lt;/span&gt;
  &lt;span property=&quot;foaf:givenName&quot;&gt;Albert&lt;/span&gt;
&lt;/div&gt;</pre>
            <p>Similarly, </p>
            <pre class="example">&lt;div about=&quot;http://dbpedia.org/resource/Albert_Einstein&quot;&gt;
  &lt;div rel=&quot;dbp:birthPlace&quot; <span class="hilite">typeof=&quot;http://schema.org/Country&quot;</span>&gt;
    &lt;span property=&quot;dbp:conventionalLongName&quot;&gt;the German Empire&lt;/span&gt;
  &lt;/div&gt;
&lt;/div&gt;</pre>
            <p>generates:</p>
            <pre class="example">&lt;http://dbpedia.org/resource/Albert_Einstein&quot;&gt; dbp:birthPlace _:b .
_:b dbp:conventionalLongName &quot;the German Empire&quot; .</pre>
            <div class="explanation"> A <a class="tref" title="bnode" href="#T-bnode">bnode</a> is simply a unique
              identifier that is only available to the processor, not to any
              external software. By generating values internally, the processor
              is able to keep track of properties for <code>_:a</code> as being
              distinct from <code>_:b</code>. But by not exposing these values
              to any external software, it is possible to have complete control
              over the identifier, as well as preventing further statements
              being made about the item. </div>
            <div id="chaining-with--property-and--typeof" typeof="bibo:Chapter" about="#chaining-with--property-and--typeof" class="section">
              <h6><span class="secno">8.1.1.3.1 </span>Chaining with <a class="aref" href="#A-property" title="property">@property</a> and <a class="aref" href="#A-typeof" title="typeof">@typeof</a></h6>
              <p>As emphasized in the <a href="#s_chaining">section on chaining</a>,
                one of the main differences between <a class="aref" href="#A-property" title="property">@property</a> and <a class="aref" href="#A-rel" title="rel">@rel</a>
                (or <a class="aref" href="#A-rev" title="rev">@rev</a>) is that the former does not induce
                chaining. The <em>only</em> exception to this rule is when <a class="aref" href="#A-typeof" title="typeof">@typeof</a>
                is also present on the element. In that case the effect of <a class="aref" href="#A-property" title="property">@property</a>
                is identical to <a class="aref" href="#A-rel" title="rel">@rel</a>. For example, the previous
                example could have been written as: </p>
              <pre class="example">&lt;div about=&quot;http://dbpedia.org/resource/Albert_Einstein&quot;&gt;
  &lt;div property=&quot;dbp:birthPlace&quot; <span class="hilite">typeof=&quot;http://schema.org/Country&quot;</span>&gt;
    &lt;span property=&quot;dbp:conventionalLongName&quot;&gt;the German Empire&lt;/span&gt;
  &lt;/div&gt;
&lt;/div&gt;</pre>
              <p>generating the same triples as before.</p>
            </div>
          </div>
          <div id="determining-the-subject-with-neither--about-nor--typeof" typeof="bibo:Chapter" about="#determining-the-subject-with-neither--about-nor--typeof" class="section">
            <h5><span class="secno">8.1.1.4 </span>Determining the subject with neither <a class="aref" href="#A-about" title="about">@about</a> nor <a class="aref" href="#A-typeof" title="typeof">@typeof</a></h5>
            <p> As described in the previous two sections, <a class="aref" href="#A-about" title="about">@about</a>
              will always take precedence and mark a new subject, but if no <a class="aref" href="#A-about" title="about">@about</a>
              value is available then <a class="aref" href="#A-typeof" title="typeof">@typeof</a> will do the same job,
              although using an implied identifier, i.e., a <a class="tref" title="bnode" href="#T-bnode">bnode</a>.</p>
            <p> But if neither <a class="aref" href="#A-about" title="about">@about</a> or <a class="aref" href="#A-typeof" title="typeof">@typeof</a> are
              present, there are a number of ways that the subject could be
              arrived at. One of these is to 'inherit' the subject from the
              containing statement, with the value to be inherited set either
              explicitly, or implicitly. </p>
            <div id="inheriting-subject-from--resource" typeof="bibo:Chapter" about="#inheriting-subject-from--resource" class="section">
              <h6><span class="secno">8.1.1.4.1 </span>Inheriting subject from <a class="aref" href="#A-resource" title="resource">@resource</a></h6>
              <p> The most usual way that an inherited subject might get set
                would be when the parent statement has an object that is a
                resource. Returning to the earlier example, in which the long
                name for the German_Empire was added, the following markup was
                used: </p>
              <pre class="example">&lt;div about=&quot;http://dbpedia.org/resource/Albert_Einstein&quot;&gt;
  &lt;span property=&quot;foaf:name&quot;&gt;Albert Einstein&lt;/span&gt;
  &lt;span property=&quot;dbp:dateOfBirth&quot; datatype=&quot;xsd:date&quot;&gt;1879-03-14&lt;/span&gt;
  &lt;div rel=&quot;dbp:birthPlace&quot; resource=&quot;http://dbpedia.org/resource/German_Empire&quot; /&gt;
  <span class="hilite">&lt;span about=&quot;http://dbpedia.org/resource/German_Empire&quot;
    property=&quot;dbp:conventionalLongName&quot;&gt;the German Empire&lt;/span&gt;</span>
&lt;/div&gt;</pre>
              <p> In an earlier illustration the subject and object for the
                German Empire were connected by removing the <a class="aref" href="#A-resource" title="resource">@resource</a>,
                relying on the <a class="aref" href="#A-about" title="about">@about</a> to set the object: </p>
              <pre class="example">&lt;div about=&quot;http://dbpedia.org/resource/Albert_Einstein&quot;&gt;
  &lt;span property=&quot;foaf:name&quot;&gt;Albert Einstein&lt;/span&gt;
  &lt;span property=&quot;dbp:dateOfBirth&quot; datatype=&quot;xsd:date&quot;&gt;1879-03-14&lt;/span&gt;
  <span class="hilite">&lt;div rel=&quot;dbp:birthPlace&quot;&gt;</span>
    &lt;span about=&quot;http://dbpedia.org/resource/German_Empire&quot;
      property=&quot;dbp:conventionalLongName&quot;&gt;the German Empire&lt;/span&gt;
  &lt;/div&gt;
&lt;/div&gt;</pre>
              <p> but it is also possible for authors to achieve the same effect
                by removing the <a class="aref" href="#A-about" title="about">@about</a> and leaving the <a class="aref" href="#A-resource" title="resource">@resource</a>:
              </p>
              <pre class="example">&lt;div about=&quot;http://dbpedia.org/resource/Albert_Einstein&quot;&gt;
  &lt;span property=&quot;foaf:name&quot;&gt;Albert Einstein&lt;/span&gt;
  &lt;span property=&quot;dbp:dateOfBirth&quot; datatype=&quot;xsd:date&quot;&gt;1879-03-14&lt;/span&gt;
  &lt;div rel=&quot;dbp:birthPlace&quot; <span class="hilite">resource=&quot;http://dbpedia.org/resource/German_Empire&quot;</span>&gt;
    &lt;span property=&quot;dbp:conventionalLongName&quot;&gt;the German Empire&lt;/span&gt;
  &lt;/div&gt;
&lt;/div&gt;</pre>
              <p> In this situation, all statements that are 'contained' by the
                object resource representing the German Empire (the value in <a class="aref" href="#A-resource" title="resource">@resource</a>)
                will have the same subject, making it easy for authors to add
                additional statements: </p>
              <pre class="example">&lt;div about=&quot;http://dbpedia.org/resource/Albert_Einstein&quot;&gt;
  &lt;span property=&quot;foaf:name&quot;&gt;Albert Einstein&lt;/span&gt;
  &lt;span property=&quot;dbp:dateOfBirth&quot; datatype=&quot;xsd:date&quot;&gt;1879-03-14&lt;/span&gt;
  &lt;div rel=&quot;dbp:birthPlace&quot; resource=&quot;http://dbpedia.org/resource/German_Empire&quot;&gt;
    &lt;span property=&quot;dbp:conventionalLongName&quot;&gt;the German Empire&lt;/span&gt;
    <span class="hilite">&lt;span rel=&quot;dbp-owl:capital&quot; resource=&quot;http://dbpedia.org/resource/Berlin&quot; /&gt;</span>
  &lt;/div&gt;
&lt;/div&gt;</pre>
              <p>Looking at the triples that an RDFa Processor would generate,
                we can see that we actually have two groups of statements; the
                first group are set to refer to the <a class="aref" href="#A-about" title="about">@about</a> that
                contains them:</p>
              <pre class="example">&lt;http://dbpedia.org/resource/Albert_Einstein&gt; foaf:name &quot;Albert Einstein&quot; .
&lt;http://dbpedia.org/resource/Albert_Einstein&gt; dbp:dateOfBirth &quot;1879-03-14&quot;^^xsd:date .
&lt;http://dbpedia.org/resource/Albert_Einstein&gt; dbp:birthPlace &lt;http://dbpedia.org/resource/German_Empire&gt; .</pre>
              <p>whilst the second group refer to the <a class="aref" href="#A-resource" title="resource">@resource</a>
                that contains them:</p>
              <pre class="example">&lt;http://dbpedia.org/resource/German_Empire&gt;
  dbp:conventionalLongName &quot;the German Empire&quot; .
&lt;http://dbpedia.org/resource/German_Empire&gt;
  dbp-owl:capital &lt;http://dbpedia.org/resource/Berlin&gt; .</pre>
              <p> Note also that the same principle described here applies to <a class="aref" href="#A-src" title="src">@src</a>
                and <a class="aref" href="#A-href" title="href">@href</a>. </p>
            </div>
            <div id="inheriting-an-anonymous-subject" typeof="bibo:Chapter" about="#inheriting-an-anonymous-subject" class="section">
              <h6><span class="secno">8.1.1.4.2 </span>Inheriting an anonymous subject</h6>
              <p> There will be occasions when the author wants to connect the
                subject and object as shown above, but is not concerned to name
                the resource that is common to the two statements (i.e., the
                object of the first statement, which is the subject of the
                second). For example, to indicate that Einstein was influenced
                by Spinoza the following markup could well be used: </p>
              <pre class="example">&lt;div about=&quot;http://dbpedia.org/resource/Baruch_Spinoza&quot; rel=&quot;dbp-owl:influenced&quot;&gt;
  &lt;div about=&quot;http://dbpedia.org/resource/Albert_Einstein&quot;&gt;
    &lt;span property=&quot;foaf:name&quot;&gt;Albert Einstein&lt;/span&gt;
    &lt;span property=&quot;dbp:dateOfBirth&quot; datatype=&quot;xsd:date&quot;&gt;1879-03-14&lt;/span&gt;
  &lt;/div&gt;
&lt;/div&gt;</pre>
              <p> An RDFa Processor will generate the following triples: </p>
              <pre class="example">&lt;http://dbpedia.org/resource/Baruch_Spinoza&gt;
  dbp-owl:influenced &lt;http://dbpedia.org/resource/Albert_Einstein&gt; .
&lt;http://dbpedia.org/resource/Albert_Einstein&gt; foaf:name &quot;Albert Einstein&quot; .
&lt;http://dbpedia.org/resource/Albert_Einstein&gt; dbp:dateOfBirth &quot;1879-03-14&quot;^^xsd:date .</pre>
              <p> However, an author could just as easily say that Spinoza
                influenced <em>something by the name of Albert Einstein, that
                  was born on March 14th, 1879</em>: </p>
              <pre class="example">&lt;div about=&quot;http://dbpedia.org/resource/Baruch_Spinoza&quot; rel=&quot;dbp-owl:influenced&quot;&gt;
  <span class="hilite">&lt;div&gt;</span>
    &lt;span property=&quot;foaf:name&quot;&gt;Albert Einstein&lt;/span&gt;
    &lt;span property=&quot;dbp:dateOfBirth&quot; datatype=&quot;xsd:date&quot;&gt;1879-03-14&lt;/span&gt;
  <span class="hilite">&lt;/div&gt;</span>
&lt;/div&gt;</pre>
              <p> In RDF terms, the item that 'represents' Einstein is <em>anonymous</em>,
                since it has no IRI to identify it. However, the item is given
                an automatically generated <a class="tref" title="bnode" href="#T-bnode">bnode</a>, and it is onto
                this identifier that all child statements are attached: </p>
              <p> An RDFa Processor will generate the following triples: </p>
              <pre class="example">&lt;http://dbpedia.org/resource/Baruch_Spinoza&gt; dbp-owl:influenced _:a .
_:a foaf:name &quot;Albert Einstein&quot; .
_:a dbp:dateOfBirth &quot;1879-03-14&quot;^^xsd:date .</pre>
              <p> Note that the <code>div</code> is superfluous, and an RDFa
                Processor will create the intermediate object even if the
                element is removed: </p>
              <pre class="example">&lt;div about=&quot;http://dbpedia.org/resource/Baruch_Spinoza&quot; rel=&quot;dbp-owl:influenced&quot;&gt;
  &lt;span property=&quot;foaf:name&quot;&gt;Albert Einstein&lt;/span&gt;
  &lt;span property=&quot;dbp:dateOfBirth&quot; datatype=&quot;xsd:date&quot;&gt;1879-03-14&lt;/span&gt;
&lt;/div&gt;</pre>
              <p> An alternative pattern is to <em>keep</em> the <code>div</code>
                and move the <a class="aref" href="#A-rel" title="rel">@rel</a> onto it: </p>
              <pre class="example">&lt;div about=&quot;http://dbpedia.org/resource/Baruch_Spinoza&quot;&gt;
  &lt;div <span class="hilite">rel=&quot;dbp-owl:influenced&quot;</span>&gt;
    &lt;span property=&quot;foaf:name&quot;&gt;Albert Einstein&lt;/span&gt;
    &lt;span property=&quot;dbp:dateOfBirth&quot; datatype=&quot;xsd:date&quot;&gt;1879-03-14&lt;/span&gt;
  &lt;/div&gt;
&lt;/div&gt;</pre>
              <p> From the point of view of the markup, this latter layout is to
                be preferred, since it draws attention to the 'hanging rel'. But
                from the point of view of an RDFa Processor, all of these
                permutations need to be supported. </p>
            </div>
          </div>
        </div>
      </div>
      <div id="s_Completing_Incomplete_Triples" typeof="bibo:Chapter" about="#s_Completing_Incomplete_Triples" class="section">
        <h3><span class="secno">8.2 </span>Completing incomplete triples'</h3>
        <p> When a new subject is calculated, it is also used to complete any
          incomplete triples that are pending. This situation arises when the
          author wants to 'chain' a number of statements together. For example,
          an author could have a statement that Albert Einstein was born in the
          German Empire: </p>
        <pre class="example">&lt;div about=&quot;http://dbpedia.org/resource/Albert_Einstein&quot;&gt;
  &lt;span property=&quot;foaf:name&quot;&gt;Albert Einstein&lt;/span&gt;
  &lt;span property=&quot;dbp:dateOfBirth&quot; datatype=&quot;xsd:date&quot;&gt;1879-03-14&lt;/span&gt;
  <span class="hilite">&lt;div rel=&quot;dbp:birthPlace&quot; resource=&quot;http://dbpedia.org/resource/German_Empire&quot; /&gt;</span>
&lt;/div&gt;</pre>
        <p> and then a further statement that the 'long name' for this country
          is <em>the German Empire</em>: </p>
        <pre class="example">&lt;span about=&quot;http://dbpedia.org/resource/German_Empire&quot;
  property=&quot;dbp:conventionalLongName&quot;&gt;the German Empire&lt;/span&gt;</pre>
        <p> RDFa allows authors to insert this statement as a self-contained
          unit into other contexts: </p>
        <pre class="example">&lt;div about=&quot;http://dbpedia.org/resource/Albert_Einstein&quot;&gt;
  &lt;span property=&quot;foaf:name&quot;&gt;Albert Einstein&lt;/span&gt;
  &lt;span property=&quot;dbp:dateOfBirth&quot; datatype=&quot;xsd:date&quot;&gt;1879-03-14&lt;/span&gt;
  &lt;div rel=&quot;dbp:birthPlace&quot; resource=&quot;http://dbpedia.org/resource/German_Empire&quot; /&gt;
  <span class="hilite">&lt;span about=&quot;http://dbpedia.org/resource/German_Empire&quot;
    property=&quot;dbp:conventionalLongName&quot;&gt;the German Empire&lt;/span&gt;</span>
&lt;/div&gt;</pre>
        <p> But it also allows authors to avoid unnecessary repetition and to
          'normalize' out duplicate identifiers, in this case the one for the
          German Empire: </p>
        <pre class="example">&lt;div about=&quot;http://dbpedia.org/resource/Albert_Einstein&quot;&gt;
  &lt;span property=&quot;foaf:name&quot;&gt;Albert Einstein&lt;/span&gt;
  &lt;span property=&quot;dbp:dateOfBirth&quot; datatype=&quot;xsd:date&quot;&gt;1879-03-14&lt;/span&gt;
  <span class="hilite">&lt;div rel=&quot;dbp:birthPlace&quot;&gt;</span>
    &lt;span about=&quot;http://dbpedia.org/resource/German_Empire&quot;
      property=&quot;dbp:conventionalLongName&quot;&gt;the German Empire&lt;/span&gt;
  &lt;/div&gt;
&lt;/div&gt;</pre>
        <p> When this happens the <a class="aref" href="#A-rel" title="rel">@rel</a> for 'birth place' is
          regarded as a 'hanging rel' because it has not yet generated any
          triples, but these 'incomplete triples' are completed by the <a class="aref" href="#A-about" title="about">@about</a>
          that appears on the next line. The first step is therefore to store
          the two parts of the triple that the RDFa Processor <em>does</em>
          have, but without an object: </p>
        <pre class="example">&lt;http://dbpedia.org/resource/Albert_Einstein&gt; dbp:birthPlace <span class="hilite">?</span> .</pre>
        <p> Then as processing continues, the RDFa Processor encounters the
          subject of the statement about the long name for the German Empire,
          and this is used in two ways. First it is used to complete the
          'incomplete triple': </p>
        <pre class="example">&lt;http://dbpedia.org/resource/Albert_Einstein&gt; 
      dbp:birthPlace <span class="hilite">&lt;http://dbpedia.org/resource/German_Empire&gt;</span> .</pre>
        <p>and second it is used to generate its own triple:</p>
        <pre class="example">&lt;http://dbpedia.org/resource/German_Empire&gt; 
      dbp:conventionalLongName &quot;the German Empire&quot; .</pre>
        <p> Note that each occurrence of <a class="aref" href="#A-about" title="about">@about</a> will complete any
          incomplete triples. For example, to mark up the fact that Albert
          Einstein had a residence both in the German Empire and Switzerland, an
          author need only specify one <a class="aref" href="#A-rel" title="rel">@rel</a> value that is then used
          with multiple <a class="aref" href="#A-about" title="about">@about</a> values: </p>
        <pre class="example">&lt;div about=&quot;http://dbpedia.org/resource/Albert_Einstein&quot; rel=&quot;dbp-owl:residence&quot;&gt;
  <span class="hilite">&lt;span about=&quot;http://dbpedia.org/resource/German_Empire&quot; /&gt;</span>
  <span class="hilite">&lt;span about=&quot;http://dbpedia.org/resource/Switzerland&quot; /&gt;</span>
&lt;/div&gt;</pre>
        <p> In this example there is one incomplete triple: </p>
        <pre class="example">&lt;http://dbpedia.org/resource/Albert_Einstein&gt; dbp-owl:residence <span class="hilite">?</span> .</pre>
        <p> When the processor meets each of the <a class="aref" href="#A-about" title="about">@about</a> values,
          this triple is completed, giving: </p>
        <pre class="example">&lt;http://dbpedia.org/resource/Albert_Einstein&gt;
  dbp-owl:residence <span class="hilite">&lt;http://dbpedia.org/resource/German_Empire&gt;</span> .
&lt;http://dbpedia.org/resource/Albert_Einstein&gt;
  dbp-owl:residence <span class="hilite">&lt;http://dbpedia.org/resource/Switzerland&gt;</span> .</pre>
        <p> These examples show how <a class="aref" href="#A-about" title="about">@about</a> completes triples, but
          there are other situations that can have the same effect. For example,
          when <a class="aref" href="#A-typeof" title="typeof">@typeof</a> creates a new <a class="tref" title="bnode" href="#T-bnode">bnode</a> (as
          described above), that will be used to complete any 'incomplete
          triples'. To illustrate, to indicate that Spinoza influenced both
          Einstein and Schopenhauer, the following markup could be used: </p>
        <pre class="example">&lt;div about=&quot;http://dbpedia.org/resource/Baruch_Spinoza&quot;&gt;
  &lt;div rel=&quot;dbp-owl:influenced&quot;&gt;
    &lt;div <span class="hilite">typeof=&quot;foaf:Person&quot;</span>&gt;
      &lt;span property=&quot;foaf:name&quot;&gt;Albert Einstein&lt;/span&gt;
      &lt;span property=&quot;dbp:dateOfBirth&quot; datatype=&quot;xsd:date&quot;&gt;1879-03-14&lt;/span&gt;
    &lt;/div&gt;
    &lt;div <span class="hilite">typeof=&quot;foaf:Person&quot;</span>&gt;
      &lt;span property=&quot;foaf:name&quot;&gt;Arthur Schopenhauer&lt;/span&gt;
      &lt;span property=&quot;dbp:dateOfBirth&quot; datatype=&quot;xsd:date&quot;&gt;1788-02-22&lt;/span&gt;
    &lt;/div&gt;          
  &lt;/div&gt;
&lt;/div&gt;</pre>
        <p>First the following incomplete triple is stored:</p>
        <pre class="example">&lt;http://dbpedia.org/resource/Baruch_Spinoza&gt; dbp-owl:influenced <span class="hilite">?</span> .</pre>
        <p> Then when the RDFa Processor processes the two occurrences of <a class="aref" href="#A-typeof" title="typeof">@typeof</a>,
          each generates a <a class="tref" title="bnode" href="#T-bnode">bnode</a>, which is used to both complete
          the 'incomplete triple', and to set the subject for further
          statements: </p>
        <pre class="example">&lt;http://dbpedia.org/resource/Baruch_Spinoza&quot;&gt; dbp-owl:influenced <span class="hilite">_:a</span> .
<span class="hilite">_:a</span> rdf:type foaf:Person .
<span class="hilite">_:a</span> foaf:name &quot;Albert Einstein&quot; .
<span class="hilite">_:a</span> dbp:dateOfBirth &quot;1879-03-14&quot;^^xsd:date .
&lt;http://dbpedia.org/resource/Baruch_Spinoza&quot;&gt; dbp-owl:influenced <span class="hilite">_:b</span> .
<span class="hilite">_:b</span> rdf:type foaf:Person .
<span class="hilite">_:b</span> foaf:name &quot;Arthur Schopenhauer&quot; .
<span class="hilite">_:b</span> dbp:dateOfBirth &quot;1788-02-22&quot;^^xsd:date .</pre>
        <p> Triples are also 'completed' if any one of <a class="aref" href="#A-property" title="property">@property</a>, <a class="aref" href="#A-rel" title="rel">@rel</a>
          or <a class="aref" href="#A-rev" title="rev">@rev</a> are present. However, unlike the situation when <a class="aref" href="#A-about" title="about">@about</a>
          or <a class="aref" href="#A-typeof" title="typeof">@typeof</a> are present, all predicates are attached to
          one <a class="tref" title="bnode" href="#T-bnode">bnode</a>: </p>
        <pre class="example">&lt;div about=&quot;http://dbpedia.org/resource/Baruch_Spinoza&quot; rel=&quot;dbp-owl:influenced&quot;&gt;
  &lt;span property=&quot;foaf:name&quot;&gt;Albert Einstein&lt;/span&gt;
  &lt;span property=&quot;dbp:dateOfBirth&quot; datatype=&quot;xsd:date&quot;&gt;1879-03-14&lt;/span&gt;
  &lt;div rel=&quot;dbp-owl:residence&quot;&gt;
    &lt;span about=&quot;http://dbpedia.org/resource/German_Empire&quot; /&gt;
    &lt;span about=&quot;http://dbpedia.org/resource/Switzerland&quot; /&gt;
  &lt;/div&gt;
&lt;/div&gt;</pre>
        <p> This example has two 'hanging rels', and so two situations when
          'incomplete triples' will be created. Processing would proceed as
          follows; first an incomplete triple is stored: </p>
        <pre class="example">&lt;http://dbpedia.org/resource/Baruch_Spinoza&gt; dbp-owl:influenced <span class="hilite">?</span> .</pre>
        <p> Next, the RDFa Processor processes the predicate values for <code>foaf:name</code>,
          <code>dbp:dateOfBirth</code> and <code>dbp-owl:residence</code>, but
          note that only the first needs to 'complete' the 'hanging rel'. So
          processing <code>foaf:name</code> generates two triples: </p>
        <pre class="example">&lt;http://dbpedia.org/resource/Baruch_Spinoza&gt; dbp-owl:influenced <span class="hilite">_:a</span> .
<span class="hilite">_:a</span> foaf:name &quot;Albert Einstein&quot; .</pre>
        <p> but processing <code>dbp:dateOfBirth</code> generates only one: </p>
        <pre class="example"><span class="hilite">_:a</span> dbp:dateOfBirth &quot;1879-03-14&quot;^^xsd:date .</pre>
        <p>Processing <code>dbp-owl:residence</code> also uses the same <a class="tref" title="bnode" href="#T-bnode">bnode</a>,
          but note that it also generates its own 'incomplete triple':</p>
        <pre class="example">_:a dbp-owl:residence <span class="hilite">?</span> .</pre>
        <p>As before, the two occurrences of <a class="aref" href="#A-about" title="about">@about</a> complete the
          'incomplete triple', once each:</p>
        <pre class="example">_:a dbp-owl:residence <span class="hilite">&lt;http://dbpedia.org/resource/German_Empire&gt;</span> .
_:a dbp-owl:residence <span class="hilite">&lt;http://dbpedia.org/resource/Switzerland&gt;</span> .</pre>
        <p> The entire set of triples that an RDFa Processor should generate are
          as follows: </p>
        <pre class="example">&lt;http://dbpedia.org/resource/Baruch_Spinoza&gt; dbp-owl:influenced <span class="hilite">_:a</span> .
<span class="hilite">_:a</span> foaf:name &quot;Albert Einstein&quot; .
<span class="hilite">_:a</span> dbp:dateOfBirth &quot;1879-03-14&quot;^^xsd:date .
<span class="hilite">_:a</span> dbp-owl:residence &lt;http://dbpedia.org/resource/German_Empire&gt; .
<span class="hilite">_:a</span> dbp-owl:residence &lt;http://dbpedia.org/resource/Switzerland&gt; .</pre> </div>
      <div id="object-resolution" typeof="bibo:Chapter" about="#object-resolution" class="section">
        <h3><span class="secno">8.3 </span>Object resolution</h3>
        <p> Although objects have been discussed in the previous sections, as
          part of the explanation of subject resolution, chaining, evaluation
          contexts, and so on, this section will look at objects in more detail.
        </p>
        <p>There are two types of object, <a class="tref" title="iri-resource" href="#T-iri-resource">IRI resource</a>s and <a class="tref" title="literal" href="#T-literal">literal</a>s.</p>
        <p> A <a class="tref" title="literal" href="#T-literal">literal</a> object can be set by using <a class="aref" href="#A-property" title="property">@property</a>
          to express a <a class="tref" title="predicate" href="#T-predicate">predicate</a>, and then using either <a class="aref" href="#A-content" title="content">@content</a>,
          or the inline text of the element that <a class="aref" href="#A-property" title="property">@property</a> is on. <em>Note

            that the use of <a class="aref" href="#A-content" title="content">@content</a> prohibits the inclusion of
            rich markup in your literal. If the inline content of an element
            accurately represents the object, then documents should rely upon
            that rather than duplicating that data using the <a class="aref" href="#A-content" title="content">@content</a>.</em></p>
        <p>A <dfn title="iri-resource" id="T-iri-resource">IRI resource</dfn> object can be set using one of <a class="aref" href="#A-rel" title="rel">@rel</a>
          or <a class="aref" href="#A-rev" title="rev">@rev</a> to express a <a class="tref" title="predicate" href="#T-predicate">predicate</a>, and then <em>either</em>
          using one of <a class="aref" href="#A-href" title="href">@href</a>, <a class="aref" href="#A-resource" title="resource">@resource</a> or <a class="aref" href="#A-src" title="src">@src</a>
          to provide an object resource explicitly, <em>or</em> using the
          chaining techniques described above to obtain an object from a nested
          subject, or from a <a class="tref" title="bnode" href="#T-bnode">bnode</a>. <em>Alternatively</em>, the <a class="aref" href="#A-property" title="property">@property</a>
          can also be used to define an IRI resource, in the presence of an <a class="aref" href="#A-href" title="href">@href</a>,
          <a class="aref" href="#A-resource" title="resource">@resource</a>, or <a class="aref" href="#A-src" title="src">@src</a> <em>and</em> in the
          absence of <a class="aref" href="#A-rel" title="rel">@rel</a>, <a class="aref" href="#A-rev" title="rev">@rev</a>, <a class="aref" href="#A-datatype" title="datatype">@datatype</a>,
          or <a class="aref" href="#A-content" title="content">@content</a>.</p>
        <div id="object-resolution-for-the--property-attribute" typeof="bibo:Chapter" about="#object-resolution-for-the--property-attribute" class="section">
          <h4><span class="secno">8.3.1 </span>Object resolution for the <a class="aref" href="#A-property" title="property">@property</a> attribute</h4>
          <p> An <dfn title="object-literal" id="T-object-literal">object literal</dfn> will be generated when <a class="aref" href="#A-property" title="property">@property</a>
            is present. <a class="aref" href="#A-property" title="property">@property</a> provides the predicate, and the
            following sections describe how the actual literal to be generated
            is determined. </p>
          <div style="margin: 0pt auto; text-align: center;"> <object data="Literal_Resolution.svg" type="image/svg+xml" height="75%" width="75%">
              <img src="Literal_Resolution.png" alt="Literal object resolution" />
            </object>
            <p><strong>Literal object resolution</strong></p>
          </div>
          <div id="plain-literals-1" typeof="bibo:Chapter" about="#plain-literals-1" class="section">
            <h5><span class="secno">8.3.1.1 </span>Plain Literals</h5>
            <p><a class="aref" href="#A-content" title="content">@content</a> can be used to indicate a <a class="tref" title="plain-literal" href="#T-plain-literal">plain
                literal</a>, as follows:</p>
            <pre class="example">&lt;meta about=&quot;http://internet-apps.blogspot.com/&quot;
      property=&quot;dc:creator&quot; <span class="hilite">content=&quot;Mark Birbeck&quot;</span> /&gt;</pre>
            <p>The <a class="tref" title="plain-literal" href="#T-plain-literal">plain literal</a> can also be specified by using
              the content of the element:</p>
            <pre class="example">&lt;span about=&quot;http://internet-apps.blogspot.com/&quot;
      property=&quot;dc:creator&quot;&gt;<span class="hilite">Mark Birbeck</span>&lt;/span&gt;</pre>
            <p> Both of these examples give the following triple: </p>
            <pre class="example">&lt;http://internet-apps.blogspot.com/&gt; dc:creator &quot;Mark Birbeck&quot; .</pre>
            <p>The value of <a class="aref" href="#A-content" title="content">@content</a> is given precedence over any
              element content, so the following would give exactly the same
              triple as shown above:</p>
            <pre class="example">&lt;span about=&quot;http://internet-apps.blogspot.com/&quot;
      property=&quot;dc:creator&quot; <span class="hilite">content=&quot;Mark Birbeck&quot;</span>&gt;John Doe&lt;/span&gt;</pre>
            <div id="language-tags" typeof="bibo:Chapter" about="#language-tags" class="section">
              <h6><span class="secno">8.3.1.1.1 </span>Language Tags</h6>
              <p>RDF allows <a class="tref" title="plain-literal" href="#T-plain-literal">plain literal</a>s to have a language tag,
                as illustrated by the following example from [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-TESTCASES">RDF-TESTCASES</a></cite>]:</p>
              <pre class="example">&lt;http://example.org/node&gt; 
  &lt;http://example.org/property&gt; &quot;chat&quot;<span class="hilite">@fr</span> .</pre>
              <p>In RDFa the Host Language may provide a mechanism for setting
                the language tag. In XHTML+RDFa [<cite><a class="bibref" rel="biblioentry" href="#bib-XHTML-RDFA">XHTML-RDFA</a></cite>], for example,
                the XML language attribute <span class="aref">@xml:lang</span>
                or the attribute <span class="aref">@lang</span> is used to add
                this information, whether the plain literal is designated by <a class="aref" href="#A-content" title="content">@content</a>,
                or by the inline text of the element:</p>
              <pre class="example">&lt;meta about=&quot;http://example.org/node&quot;
  property=&quot;ex:property&quot; <span class="hilite">xml:lang=&quot;fr&quot;</span> content=&quot;chat&quot; /&gt;</pre>
              <p>Note that the language value can be inherited as defined in
                [<cite><a class="bibref" rel="biblioentry" href="#bib-XML10-4e">XML10-4e</a></cite>], so the following syntax will give the same triple
                as above:</p>
              <pre class="example">&lt;html xmlns=&quot;http://www.w3.org/1999/xhtml&quot; 
      prefix=&quot;ex: http://www.example.com/ns/&quot; <span class="hilite">xml:lang=&quot;fr&quot;</span>&gt;
  &lt;head&gt;
    &lt;title xml:lang=&quot;en&quot;&gt;Example&lt;/title&gt;
    &lt;meta about=&quot;http://example.org/node&quot;
      property=&quot;ex:property&quot; content=&quot;chat&quot; /&gt;
  &lt;/head&gt;
  ...
&lt;/html&gt;</pre> </div>
          </div>
          <div id="typed-literals-1" typeof="bibo:Chapter" about="#typed-literals-1" class="section">
            <h5><span class="secno">8.3.1.2 </span>Typed literals</h5>
            <p>Literals can be given a data type using <a class="aref" href="#A-datatype" title="datatype">@datatype</a>.</p>
            <p>This can be represented in RDFa as follows:</p>
            <pre class="example">&lt;span property=&quot;cal:dtstart&quot; content=&quot;2015-09-16T16:00:00-05:00&quot; 
      <span class="hilite">datatype=&quot;xsd:dateTime&quot;</span>&gt;
  September 16th at 4pm
&lt;/span&gt;.</pre>
            <p>The triples that this markup generates include the datatype after
              the literal:</p>
            <pre class="example">&lt;&gt; cal:dtstart &quot;2015-09-16T16:00:00-05:00&quot;^^<span class="hilite">xsd:dateTime</span> .</pre> </div>
          <div id="s-xml-literals" typeof="bibo:Chapter" about="#s-xml-literals" class="section">
            <h5><span class="secno">8.3.1.3 </span><dfn title="xml-literals" id="T-xml-literals">XML Literals</dfn></h5>
            <p>XML documents cannot contain XML markup in their attributes,
              which means it is not possible to represent XML within <a class="aref" href="#A-content" title="content">@content</a>
              (the following would cause an XML parser to generate an error):</p>
            <pre class="example">&lt;head&gt;
  &lt;meta property=&quot;dc:title&quot;
    <span class="hilite">content=&quot;E = mc&lt;sup&gt;2&lt;/sup&gt;: The Most Urgent Problem of Our Time&quot;</span> /&gt;
&lt;/head&gt;</pre>
            <p>RDFa therefore supports the use of normal markup to express XML
              literals, by using <a class="aref" href="#A-datatype" title="datatype">@datatype</a>:</p>
            <pre class="example">&lt;h2 property=&quot;dc:title&quot; datatype=&quot;rdf:XMLLiteral&quot;&gt;
  <span class="hilite">E = mc&lt;sup&gt;2&lt;/sup&gt;: The Most Urgent Problem of Our Time</span>
&lt;/h2&gt;</pre>
            <p>This would generate the following triple, with the XML preserved
              in the literal:</p>
            <pre class="example">&lt;&gt; dc:title &quot;E = mc&lt;sup&gt;2&lt;/sup&gt;: The Most Urgent Problem of Our Time&quot;^^rdf:XMLLiteral .</pre>
            <p class="note"> This requires that an IRI mapping for the prefix <code>rdf</code>
              has been defined. </p>
            <p> In the examples given here the <code>sup</code> element is
              actually part of the meaning of the literal, but there will be
              situations where the extra markup means nothing, and can therefore
              be ignored. In this situation omitting the <a class="aref" href="#A-datatype" title="datatype">@datatype</a>
              attribute or specifying an empty <a class="aref" href="#A-datatype" title="datatype">@datatype</a> value can
              be used create a plain literal: </p>
            <pre class="example">&lt;p&gt;You searched for &lt;strong&gt;Einstein&lt;/strong&gt;:&lt;/p&gt;
&lt;p about=&quot;http://dbpedia.org/resource/Albert_Einstein&quot;&gt;
  &lt;span property=&quot;foaf:name&quot; <span class="hilite">datatype=&quot;&quot;</span>&gt;Albert &lt;strong&gt;Einstein&lt;/strong&gt;&lt;/span&gt;
  (b. March 14, 1879, d. April 18, 1955) was a German-born theoretical physicist.
&lt;/p&gt;</pre>
            <p>Although the rendering of this page has highlighted the term the
              user searched for, setting <a class="aref" href="#A-datatype" title="datatype">@datatype</a> to nothing
              ensures that the data is interpreted as a plain literal, giving
              the following triples:</p>
            <pre class="example">&lt;http://dbpedia.org/resource/Albert_Einstein&gt; foaf:name <span class="hilite">&quot;Albert Einstein&quot;</span> .</pre>
            <p class="note">The value of this <a class="tref" title="xml-literals" href="#T-xml-literals">XML
                Literal</a> is the exclusive canonicalization
              [<cite><a class="bibref" rel="biblioentry" href="#bib-XML-EXC-C14N">XML-EXC-C14N</a></cite>] of the RDFa element's value.</p>
          </div>
        </div>
        <div id="iri-object-resolution" typeof="bibo:Chapter" about="#iri-object-resolution" class="section">
          <h4><span class="secno">8.3.2 </span>IRI object resolution</h4>
          <p> Most of the rules governing the processing of objects that are
            resources are to be found in the processing descriptions given
            above, since they are important for establishing the subject. This
            section aims to highlight general concepts, and anything that might
            have been missed. </p>
          <p> One or more <dfn title="iri-object" id="T-iri-object">IRI object</dfn>s are needed when <a class="aref" href="#A-rel" title="rel">@rel</a>,
            <a class="aref" href="#A-rev" title="rev">@rev</a>, or <a class="aref" href="#A-property" title="property">@property</a> is present. Each
            attribute will cause triples to be generated when used with <a class="aref" href="#A-href" title="href">@href</a>,
            <a class="aref" href="#A-resource" title="resource">@resource</a> or <a class="aref" href="#A-src" title="src">@src</a>, or with the subject
            value of any nested statement if none of these attributes are
            present. </p>
          <p> <a class="aref" href="#A-rel" title="rel">@rel</a> and <a class="aref" href="#A-rev" title="rev">@rev</a> are essentially the
            inverse of each other; whilst <a class="aref" href="#A-rel" title="rel">@rel</a> establishes a
            relationship between the <a class="tref" title="current-subject" href="#T-current-subject">current subject</a> as subject,
            and the <a class="tref" title="current-object-resource" href="#T-current-object-resource">current object resource</a> as the object, <a class="aref" href="#A-rev" title="rev">@rev</a>
            does the exact opposite, and uses the <a class="tref" title="current-object-resource" href="#T-current-object-resource">current object resource</a>
            as the subject, and the <a class="tref" title="current-subject" href="#T-current-subject">current subject</a> as the object.
          </p>
          <div id="using--resource-to-set-the-object" typeof="bibo:Chapter" about="#using--resource-to-set-the-object" class="section">
            <h5><span class="secno">8.3.2.1 </span>Using <a class="aref" href="#A-resource" title="resource">@resource</a> to set the object</h5>
            <p>RDFa provides the <a class="aref" href="#A-resource" title="resource">@resource</a> attribute as a way to
              set the object of statements. This is particularly useful when
              referring to resources that are not themselves navigable links:</p>
            <pre class="example">&lt;html&gt;
  &lt;head&gt;
    &lt;title&gt;On Crime and Punishment&lt;/title&gt;
    &lt;base href=&quot;http://www.example.com/candp.xhtml&quot; /&gt;
  &lt;/head&gt;
  &lt;body&gt;
    &lt;blockquote about=&quot;#q1&quot; rel=&quot;dc:source&quot; <span class="hilite">resource=&quot;urn:ISBN:0140449132&quot;</span> &gt;
      &lt;p id=&quot;q1&quot;&gt;
        Rodion Romanovitch! My dear friend! If you go on in this way
        you will go mad, I am positive! Drink, pray, if only a few drops!
      &lt;/p&gt;
    &lt;/blockquote&gt;
  &lt;/body&gt;
&lt;/html&gt;</pre>
            <p>The <code>blockquote</code> element generates the following
              triple:</p>
            <pre class="example">&lt;http://www.example.com/candp.xhtml#q1&gt;
  &lt;http://purl.org/dc/terms/source&gt; &lt;urn:ISBN:0140449132&gt; .</pre>
            <p>Note that, in the example above, <a class="aref" href="#A-property" title="property">@property</a> could
              have been used instead of <a class="aref" href="#A-rel" title="rel">@rel</a>, yielding the same
              triple.</p>
          </div>
          <div id="using--href-or--src" typeof="bibo:Chapter" about="#using--href-or--src" class="section">
            <h5><span class="secno">8.3.2.2 </span>Using <a class="aref" href="#A-href" title="href">@href</a> or <a class="aref" href="#A-src" title="src">@src</a></h5>
            <p> If no <a class="aref" href="#A-resource" title="resource">@resource</a> is present, then <a class="aref" href="#A-href" title="href">@href</a>
              or <a class="aref" href="#A-src" title="src">@src</a> are next in priority order for setting the
              object. </p>
            <p>When a predicate has been expressed using <a class="aref" href="#A-rel" title="rel">@rel</a>, the
              <a class="aref" href="#A-href" title="href">@href</a> or <a class="aref" href="#A-src" title="src">@src</a> on the RDFa statement's
              element is used to identify the object with a <a class="tref" title="iri-reference" href="#T-iri-reference">IRI reference</a>.
              Their types are an IRI:</p>
            <pre class="example">&lt;link about=&quot;mailto:john@example.org&quot;
      <span class="hilite">rel=&quot;foaf:knows&quot; href=&quot;mailto:sue@example.org&quot;</span> /&gt;</pre>
            <p>It's also possible to use both <a class="aref" href="#A-rel" title="rel">@rel</a> and <a class="aref" href="#A-rev" title="rev">@rev</a>
              at the same time on an element. This is particularly useful when
              two things stand in two different relationships with each other,
              for example when a picture is taken <em>by</em> Mark, but that
              picture also <em>depicts</em> him:</p>
            <pre class="example">&lt;img about=&quot;http://www.blogger.com/profile/1109404&quot;
    src=&quot;photo1.jpg&quot; <span class="hilite">rev=&quot;dc:creator&quot; rel=&quot;foaf:img&quot;</span>/&gt;</pre>
            <p>which then yields two triples:</p>
            <pre class="example">&lt;photo1.jpg&gt; 
  dc:creator &lt;http://www.blogger.com/profile/1109404&gt; .
&lt;http://www.blogger.com/profile/1109404&gt; 
  foaf:img &lt;photo1.jpg&gt; .</pre> </div>
          <div id="incomplete-triples" typeof="bibo:Chapter" about="#incomplete-triples" class="section">
            <h5 id="s_Incomplete_Triples"><span class="secno">8.3.2.3 </span>Incomplete triples</h5>
            <p>When a triple predicate has been expressed using <a class="aref" href="#A-rel" title="rel">@rel</a>
              or <a class="aref" href="#A-rev" title="rev">@rev</a>, but no <a class="aref" href="#A-href" title="href">@href</a>, <a class="aref" href="#A-src" title="src">@src</a>,
              or <a class="aref" href="#A-resource" title="resource">@resource</a> exists on the same element, there is a
              'hanging rel'. This causes the current subject and all possible
              predicates (with an indicator of whether they are 'forwards, i.e.,
              <a class="aref" href="#A-rel" title="rel">@rel</a> values, or not, i.e., <a class="aref" href="#A-rev" title="rev">@rev</a> values),
              to be stored as 'incomplete triples' pending discovery of a
              subject that could be used to 'complete' those triples.</p>
            <p>This process is described in more detail in <a href="#s_Completing_Incomplete_Triples">Completing

                'Incomplete Triples'</a>.</p>
          </div>
        </div>
      </div>
      <div id="list-generation" typeof="bibo:Chapter" about="#list-generation" class="section">
        <h3><span class="secno">8.4 </span>List generation</h3>
        <p>An RDF graph is a collection of triples. This also means that if the
          graph contains two triples sharing the same subject and predicate:</p>
        <pre class="example">&lt;http://www.example.com&gt; &lt;http://www.example.com/predicate&gt; &quot;first object&quot;, &quot;second object&quot; ;</pre>
        <p>There is no way for an application to rely on the relative order of
          the two triples when, for example, querying a database containing
          these triples. For most of the applications and data sets this is not
          a problem, but, in some cases, the order is important. A typical case
          is publications: when a book or an article has several co-authors, the
          order of the authors may be important. </p>
        <p>RDF has a set of predefined predicates that have an agreed-upon
          semantics of order. For example, the publication: “Semantic Annotation
          and Retrieval, by Ben Adida, Mark Birbeck, and Ivan Herman” could be
          described in RDF triples using these terms as follows:</p>
        <pre class="example">@prefix bibo:  &lt;http://purl.org/ontology/bibo/&gt; .
@prefix dc:    &lt;http://purl.org/dc/terms/&gt; .
@prefix rdf:   &lt;http://www.w3.org/1999/02/22-rdf-syntax-ns#&gt; .
[ a bibo:Chapter ;
  dc:title &quot;Semantic Annotation and Retrieval&quot; ;
  dc:creator [
    rdf:first &quot;Ben Adida&quot; ;
    rdf:rest [
      rdf:first &quot;Mark Birbeck&quot; ;
      rdf:rest [
        rdf:first &quot;Ivan Herman&quot; ;
        rdf:rest rdf:nil .
      ] .
    ] .
  ] .
	...
]</pre>
        <p>which conveys the notion of “order” for the three authors.
          Admittingly, this is not very readable. However, Turtle has a
          syntactic shorthand for these structures:</p>
        <pre class="example">@prefix bibo:  &lt;http://purl.org/ontology/bibo/&gt; .
@prefix dc:    &lt;http://purl.org/dc/terms/&gt; .
@prefix rdf:   &lt;http://www.w3.org/1999/02/22-rdf-syntax-ns#&gt; .
[ a bibo:Chapter ;
  dc:title &quot;Semantic Annotation and Retrieval&quot; ;
  dc:creator ( &quot;Ben Adida&quot; &quot;Mark Birbeck&quot; &quot;Ivan Herman&quot; ) .
  ...
]</pre>
        <p>It would of course be possible to reproduce the same structure in
          RDFa, using the RDF predicates <code>rdf:first</code>, <code>rdf:rest</code>,
          as well as the special resource <code>rdf:nil</code>. However, to
          make this easier, RDFa provides the <a class="aref" href="#A-inlist" title="inlist">@inlist</a>. What this
          attributes signals is that the object generated on that element should
          be put on a list; the list is used with the common predicate with the
          common subject. Here is how the previous structure could look like in
          RDFa:</p>
        <pre class="example">&lt;p prefix=&quot;bibo: http://purl.org/ontology/bibo/ dc: http://purl.org/dc/terms/ typeof=&quot;bibo:Chapter&quot;&gt;
  “&lt;span property=&quot;dc:title&quot;&gt;Semantic Annotation and Retrieval&lt;/span&gt;”, by
  &lt;span <span class="hilite">inlist=&quot;&quot;</span> <span class="hilite">property=&quot;dc:creator&quot;</span>&gt;Ben Adida&lt;/span&gt;,
  &lt;span <span class="hilite">inlist=&quot;&quot;</span> <span class="hilite">property=&quot;dc:creator&quot;</span>&gt;Mark Birbeck&lt;/span&gt;, and
  &lt;span <span class="hilite">inlist=&quot;&quot;</span> <span class="hilite">property=&quot;dc:creator&quot;</span>&gt;Ivan Herman&lt;/span&gt;.
&lt;/p&gt;</pre>
        <p>Note that the order in the list is determined by the document order.
          (The value of the <a class="aref" href="#A-inlist" title="inlist">@inlist</a> is not relevant, only its
          presence is.)</p>
        <p>Lists may also include URIs and not only literals. For example, two
          of the three co-authors could decide to publicise their FOAF address
          in the authors’ list:</p>
        <pre class="example">&lt;p prefix=&quot;bibo: http://purl.org/ontology/bibo/ dc: http://purl.org/dc/terms/ typeof=&quot;bibo:Chapter&quot;&gt;
  “&lt;span property=&quot;dc:title&quot;&gt;Semantic Annotation and Retrieval&lt;/span&gt;”, by
  &lt;span <span class="hilite">inlist=&quot;&quot;</span> <span class="hilite">property=&quot;dc:creator&quot;</span> <span class="hilite">resource=&quot;http://ben.adida.net/#me&quot;</span>&gt;Ben Adida&lt;/span&gt;,
  &lt;span <span class="hilite">inlist=&quot;&quot;</span> <span class="hilite">property=&quot;dc:creator&quot;</span>&gt;Mark Birbeck&lt;/span&gt;, and
  &lt;span <span class="hilite">inlist=&quot;&quot;</span> <span class="hilite">property=&quot;dc:creator&quot;</span> <span class="hilite">resource=&quot;http://www.ivan-herman.net/foaf#me&quot;</span>&gt;Ivan Herman&lt;/span&gt;.
&lt;/p&gt;</pre>
        <p>yielding:</p>
        <pre class="example">@prefix bibo:  &lt;http://purl.org/ontology/bibo/&gt; .
@prefix dc:    &lt;http://purl.org/dc/terms/&gt; .
@prefix rdf:   &lt;http://www.w3.org/1999/02/22-rdf-syntax-ns#&gt; .
[ a bibo:Chapter ;
  dc:title &quot;Semantic Annotation and Retrieval&quot; ;
  dc:creator ( &lt;http://ben.adida.net/#me&gt; &quot;Mark Birbeck&quot; &lt;http://www.ivan-herman.net/foaf#me&gt; ) .
  ...
]</pre>
        <p>In the example above, <a class="aref" href="#A-rel" title="rel">@rel</a> could have been used leading
          exactly to the same triples:</p>
        <pre class="example">&lt;p prefix=&quot;bibo: http://purl.org/ontology/bibo/ dc: http://purl.org/dc/terms/ typeof=&quot;bibo:Chapter&quot;&gt;
  “&lt;span property=&quot;dc:title&quot;&gt;Semantic Annotation and Retrieval&lt;/span&gt;”, by
  &lt;span <span class="hilite">inlist=&quot;&quot;</span> <span class="hilite">rel=&quot;dc:creator&quot;</span> <span class="hilite">resource=&quot;http://ben.adida.net/#me&quot;</span>&gt;Ben Adida&lt;/span&gt;,
  &lt;span <span class="hilite">inlist=&quot;&quot;</span> <span class="hilite">property=&quot;dc:creator&quot;</span>&gt;Mark Birbeck&lt;/span&gt;, and
  &lt;span <span class="hilite">inlist=&quot;&quot;</span> <span class="hilite">rel=&quot;dc:creator&quot;</span> <span class="hilite">resource=&quot;http://www.ivan-herman.net/foaf#me&quot;</span>&gt;Ivan Herman&lt;/span&gt;.
&lt;/p&gt;</pre>
        <p><a href="#s_Incomplete_Triples">Incomplete Triples</a> can also be
          used in conjunction with lists when all list elements are resources
          and not literal. For example, the previous example, this time with all
          three authors referring to their FOAF profile, could have been written
          as:</p>
        <pre class="example">&lt;p prefix=&quot;bibo: http://purl.org/ontology/bibo/ dc: http://purl.org/dc/terms/ typeof=&quot;bibo:Chapter&quot;&gt;
  “&lt;span property=&quot;dc:title&quot;&gt;Semantic Annotation and Retrieval&lt;/span&gt;”, by
   &lt;span <span class="hilite">rel=&quot;dc:creator&quot;</span> <span class="hilite">inlist=&quot;&quot;</span>&gt;
     &lt;a <span class="hilite">href=&quot;http://ben.adida.net/#me&quot;</span>&gt;Ben Adida&lt;/a&gt;,
     &lt;a <span class="hilite">href=&quot;http://internet-apps.blogspot.com/2008/03/my-profile.html#me&quot;</span>&gt;Mark Birbeck&lt;/a&gt;, and
     &lt;a <span class="hilite">href=&quot;http://www.ivan-herman.net/foaf#me&quot;</span>&gt;Ivan Herman&lt;/a&gt;.
   &lt;/span&gt;
  &lt;/p&gt;</pre>
        <p>Resulting in:</p>
        <pre class="example">@prefix bibo:  &lt;http://purl.org/ontology/bibo/&gt; .
@prefix dc:    &lt;http://purl.org/dc/terms/&gt; .
@prefix rdf:   &lt;http://www.w3.org/1999/02/22-rdf-syntax-ns#&gt; .
[ a bibo:Chapter ;
  dc:title &quot;Semantic Annotation and Retrieval&quot; ;
  dc:creator ( &lt;http://ben.adida.net/#me&gt;
               &lt;http://internet-apps.blogspot.com/2008/03/my-profile.html#me&gt;
               &lt;http://www.ivan-herman.net/foaf#me&gt; ) .
  ...
]</pre>
        <p>Note that it is also possible to generate an empty list easily,
          without <a class="aref" href="#A-inlist" title="inlist">@inlist</a>, using:</p>
        <pre class="example">&lt;span rel=&quot;prop&quot; resource=&quot;rdf:nil&quot;/&gt;</pre>
      </div>
    </div>
    <div id="s_initialcontexts" typeof="bibo:Chapter" about="#s_initialcontexts" class="section">
      
<!-- OddPage -->
<h2><span class="secno">9. </span>RDFa Initial Contexts</h2>
      <p>RDFa permits Host Languages to define an <a class="tref" title="initial-context" href="#T-initial-context">initial context</a>.
        Such a context is a collection of terms, prefix mappings, and/or default
        vocabulary declarations. An initial context is either intrinsically
        known to the parser, or it is loaded as external documents and
        processed. These documents <em class="rfc2119" title="must">must</em> be defined in an approved RDFa Host
        Language (currently XML+RDFa and XHTML+RDFa [<cite><a class="bibref" rel="biblioentry" href="#bib-XHTML-RDFA">XHTML-RDFA</a></cite>]). <span id="C16" about="#C16" resource="http://www.w3.org/2010/02/rdfa/meetings/2010-10-21#resolution_2" rel="bibo:affirmedBy">
          They <em class="rfc2119" title="may">may</em> also be defined in other formats (e.g., RDF/XML
          [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-SYNTAX-GRAMMAR">RDF-SYNTAX-GRAMMAR</a></cite>], or Turtle [<cite><a class="bibref" rel="biblioentry" href="#bib-TURTLE">TURTLE</a></cite>]).</span> When an initial
        context document is processed, it is evaluated as follows:</p>
      <ol>
        <li>Parse the content (according to the processing rules for that
          document type) and extract the triples into a collection associated
          with that IRI. Note: These triples <em class="rfc2119" title="must not">must not</em> be co-mingled with the
          triples being extracted from any other IRI. </li>
        <li>For every subject with a pair of predicates that have the values <code>rdfa:prefix</code>
          and <code>rdfa:uri</code>, create a key-value mapping from the <code>rdfa:prefix</code>
          object literal (the key) to the <code>rdfa:uri</code> object literal
          (the value). Add this mapping to the <a class="tref" title="list-of-iri-mappings" href="#T-list-of-iri-mappings">list of IRI mappings</a>
          of the <a href="#s_sequence">initial evaluation context</a>, after
          transforming the 'prefix' component to lower-case.</li>
        <li>For every subject with a pair of predicates that have the values <code>rdfa:term</code>
          and <code>rdfa:uri</code>, create a key-value mapping from the <code>rdfa:term</code>
          object literal (the key) to the <code>rdfa:uri</code> object literal
          (the value). Add this mapping to the <a class="tref" title="term-mappings" href="#T-term-mappings">term mappings</a> of
          the <a href="#s_sequence">initial evaluation context</a>.</li>
        <li>For an extracted triple that has a predicate of <code>rdfa:vocabulary</code>,
          define the <a class="tref" title="default-vocabulary" href="#T-default-vocabulary">default vocabulary</a> of the <a href="#s_sequence">initial

            evaluation context</a> to be the object literal of the <code>rdfa:vocabulary</code>
          predicate.</li>
      </ol>
      <p id="C17" about="#C17" resource="http://www.w3.org/2010/02/rdfa/meetings/2010-10-21#resolution_2" rel="bibo:affirmedBy">
        When an RDFa Initial Context is defined using an RDF serialization, it
        <em class="rfc2119" title="must">must</em> use the vocabulary terms above to declare the components of the
        context.</p>
      <p class="note">Caching of the relevant triples retrieved via this
        mechanism is <em class="rfc2119" title="recommended">recommended</em>. Embedding definitions for well known, stable
        RDFa Initial Contexts in the implementation is <em class="rfc2119" title="recommended">recommended</em>.</p>
      <p class="note">The object literal for the <code>rdfa:uri</code>
        predicate <em class="rfc2119" title="must">must</em> be an absolute IRI. The object literal for the <code>rdfa:term</code>
        predicate <em class="rfc2119" title="must">must</em> match the production for <a href="#P_term">term</a>. The
        object literal for the <code>rdfa:prefix</code> predicate must match
        the production for <a href="#P_prefix">prefix</a>. The object literal
        for the <code>rdfa:vocabulary</code> predicate <em class="rfc2119" title="must">must</em> be an absolute IRI.
        If one of the objects is not a Literal, does not match its associated
        production, if there is more than one <code>rdfa:vocabulary</code>
        predicate, or if there are additional <code>rdfa:uri</code> or <code>rdfa:term</code>
        predicates sharing the same subject, an RDFa Processor <em class="rfc2119" title="must not">must not</em> create
        the associated mapping.</p>
    </div>
    <div id="s_vocab_expansion" typeof="bibo:Chapter" about="#s_vocab_expansion" class="section">
      
<!-- OddPage -->
<h2><span class="secno">10. </span><dfn id="T-vocab-expansion">RDFa Vocabulary Expansion</dfn></h2>
      <p> Since RDFa is based on RDF, the semantics of RDF vocabularies can be
        used to gain more knowledge about data. Vocabularies, properties and
        classes are identified by IRIs, which enables them to be discoverable.
        RDF data published at the location of these IRIs can be retrieved, and
        descriptions of the properties and classes using specified semantics can
        be applied. </p>
      <p> RDFa Vocabulary Expansion is an optional processing step which may be
        added once the normal processing steps described in <a href="#s_model">Processing

          Model</a> are complete. Vocabulary expansion relies on a very small
        sub-set of OWL entailment [<cite><a class="bibref" rel="biblioentry" href="#bib-OWL2-OVERVIEW">OWL2-OVERVIEW</a></cite>] to add triples to the <a class="tref" title="output-graph" href="#T-output-graph">output

          graph</a> based on rules and property/class relationships described
        in referenced vocabularies. Vocabulary expansion <em class="rfc2119" title="may">may</em> be performed as
        part of a larger RDF toolset including, for example, an OWL 2 RL
        reasoner. Alternatively, using vocabulary data added to the <a class="tref" title="output-graph" href="#T-output-graph">output
          graph</a> in processing step 2 of <a href="#s_sequence">Sequence</a>,
        expansion <em class="rfc2119" title="may">may</em> also be done using a separate and dedicated (e.g., rule
        based) reasoner after the <a class="tref" title="output-graph" href="#T-output-graph">output graph</a> has been generated,
        or as the last processing step by an RDFa processor. </p>
      <p> It can be very useful to make generalized data available for
        subsequent usage of RDFa-embedded data by expanding inferred statements
        entailed by these semantics. This provides for existing vocabularies
        that extend well-known vocabularies to have those properties added to
        the output graph automatically. For example, the namespace document of
        the Creative Commons vocabulary, i.e., <code>http://creativecommons.org/ns</code>,
        defines <code>cc:license</code> to be a sub-property of <code>dc:license</code>.
        By using the <a class="aref" href="#A-vocab" title="vocab">@vocab</a> attribute, one can describe a licensing
        information as follows:</p>
      <pre class="example">This document is licensed under the 
&lt;a vocab=&quot;http://creativecommons.org/ns#&quot;
   rel=&quot;license&quot;
   href=&quot;http://creativecommons.org/licenses/by-nc-nd/3.0/&quot;&gt;
   Creative Commons By-NC-ND License
&lt;/a&gt;.</pre>
      <p>which results in the following <a class="tref" title="output-graph" href="#T-output-graph">output graph</a>:</p>
      <pre class="example">@prefix cc:    &lt;http://creativecommons.org/ns#&gt; .
@prefix rdfa:  &lt;http://www.w3.org/ns/rdfa#&gt; .
&lt;&gt; cc:license          &lt;http://creativecommons.org/licenses/by-nc-nd/3.0/&gt; ;
   rdfa:usesVocabulary &lt;http://creativecommons.org/ns#&gt; .</pre>
      <p>After vocabulary expansion, the <a class="tref" title="output-graph" href="#T-output-graph">output graph</a> contains:</p>
      <pre class="example">@prefix cc:    &lt;http://creativecommons.org/ns#&gt; .
@prefix rdfa:  &lt;http://www.w3.org/ns/rdfa#&gt; .
<span class="hilite">@prefix dc:    &lt;http://purl.org/dc/terms/&gt; .</span>
&lt;&gt; cc:license          &lt;http://creativecommons.org/licenses/by-nc-nd/3.0/&gt;;
   <span class="hilite">dc:license          &lt;http://creativecommons.org/licenses/by-nc-nd/3.0/&gt;</span> ;
   rdfa:usesVocabulary  &lt;http://creativecommons.org/ns#&gt; .</pre>
      <p> Other vocabularies, specifically intended to provide relations to
        multiple vocabularies, could also be defined by publishers, allowing use
        of terms in a single namespace which result in properties and/or classes
        from other primary vocabularies being imported. This benefits publishers
        as data is now more widely searchable and encourages the practice of
        referencing well-known vocabularies. </p>
      <div class="informative section" id="s_vocab_expansion_details" typeof="bibo:Chapter" about="#s_vocab_expansion_details">
        <h3><span class="secno">10.1 </span><dfn id="T-vocab_expansion_details">Details of the RDFa Vocabulary
            Expansion</dfn></h3><p><em>This section is non-normative.</em></p>
        <p> Once the <a class="tref" title="output-graph" href="#T-output-graph">output graph</a> is generated following the
          processing steps defined in <a href="#s_sequence">Sequence</a>,
          processors <em class="rfc2119" title="may">may</em> perform the following processing steps on the output
          graph. It must do so only if the user of the processor explicitly asks
          for it, as prescribed in <a href="#s_expansion_control">Vocabulary
            Expansion Control of RDFa Processors</a>. </p>
        <p> A <dfn title="vocabulary-graph" id="T-vocabulary-graph">vocabulary graph</dfn> is created as follows: For each IRI
          being the object of a triple in the <a class="tref" title="output-graph" href="#T-output-graph">output graph</a> with
          the subject being the current document (<a class="tref" title="base" href="#T-base">base</a>) IRI and the
          property being <code>rdfa:usesVocabulary</code>, that IRI is
          dereferenced. If the dereferencing yields the serialization of an RDF
          graph, that serialization is parsed and the resulting graph is merged
          with the vocabulary graph. (An RDFa processor capable of vocabulary
          expansion <em class="rfc2119" title="must">must</em> accept an RDF graph serialized in RDFa, and <em class="rfc2119" title="should">should</em>
          accept other standard serialization formats of RDF such as RDF/XML
          [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-SYNTAX-GRAMMAR">RDF-SYNTAX-GRAMMAR</a></cite>] and Turtle [<cite><a class="bibref" rel="biblioentry" href="#bib-TURTLE">TURTLE</a></cite>].) </p>
        <p class="note"> Note that if, in the second step, a particular
          vocabulary is serialized in RDFa, that particular graph is not
          expected to undergo any vocabulary expansion on its own. </p>
        <p>Vocabulary expansion is then performed as follows:</p>
        <ol>
          <li>The processor operates on the merge of the default and vocabulary
            graphs using <a href="#s_vocab_entailment">RDFa Vocabulary
              Entailment</a>.</li>
          <li>Add the new triples inferred from the <a class="tref" title="output-graph" href="#T-output-graph">output graph</a>
            using this entailment to the (expanded) <a class="tref" title="output-graph" href="#T-output-graph">output graph</a>.
            The processor <em class="rfc2119" title="should not">should not</em> add the triples appearing in the <a class="tref" title="vocabulary-graph" href="#T-vocabulary-graph">vocabulary
            graph</a> only.</li>
        </ol>
        <div class="explanation"> The goal of the second step is to avoid adding
          the “axioms”, e.g., the sub-property definitions to the output graph.
          Applications usually do not require those additional information. </div>
        <div id="s_vocab_entailment" typeof="bibo:Chapter" about="#s_vocab_entailment" class="section">
          <h4><span class="secno">10.1.1 </span><dfn id="T-vocab-entailment">RDFa Vocabulary Entailment</dfn></h4>
          <p> For the purpose of vocabulary processing, RDFa used a very
            restricted subset of the OWL vocabulary and is based on the RDF-Based
              Semantics of OWL[<cite><a class="bibref" rel="biblioentry" href="#bib-OWL2-RDF-BASED-SEMANTICS">OWL2-RDF-BASED-SEMANTICS</a></cite>]. The RDFa
            Vocabulary Entailment uses the following terms: </p>
          <ul>
            <li><code>rdf:type</code></li>
            <li><code>rdfs:subClassOf</code></li>
            <li><code>rdfs:subPropertyOf</code></li>
            <li><code>owl:equivalentClass</code></li>
            <li><code>owl:equivalentProperty</code><br />
            </li>
          </ul>
          <p class="note">and it considers only the entailment on individuals
            (i.e., not on the relationships that can be deduced on the
            properties or the classes themselves.)<br />
          </p>
          <p class="note">While the formal definition of the RDFa Entailment
            refers to the general OWL 2 Semantics, practical implementations may
            rely on a subset of the OWL 2 RL Profile’s entailment expressed in
            rules (<cite><a href="http://www.w3.org/TR/2009/REC-owl2-profiles-20091027/#Reasoning_in_OWL_2_RL_and_RDF_Graphs_using_Rules">section

                4.3</a></cite> of [<cite><a class="bibref" rel="biblioentry" href="#bib-OWL2-PROFILES">OWL2-PROFILES</a></cite>]). In particular, the
            relevant rules are (using the rule identifications in <cite><a href="http://www.w3.org/TR/2009/REC-owl2-profiles-20091027/#Reasoning_in_OWL_2_RL_and_RDF_Graphs_using_Rules">section

                4.3</a></cite> of [<cite><a class="bibref" rel="biblioentry" href="#bib-OWL2-PROFILES">OWL2-PROFILES</a></cite>]): <code>prp-spo1</code>, <code>prp-eqp1</code>,
            <code>prp-eqp2</code>, <code>cax-sco</code>, <code>cax-eqc1</code>,
            and <code>cax-eqc2</code>. </p>
          The entailment described in this section is the <em>minimum</em>
          useful level for RDFa. Processors may, of course, choose to follow
          more powerful entailment regimes, e.g., include full RDFS [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-MT">RDF-MT</a></cite>]
          or OWL [<cite><a class="bibref" rel="biblioentry" href="#bib-OWL2-OVERVIEW">OWL2-OVERVIEW</a></cite>] entailments. Using those entailments
          applications may perform datatype validation by checking <code>rdfs:range</code>
          of a property, or use the advanced facilities offered by, e.g., OWL’s
          property chains to interlink vocabularies further. </div>
      </div>
      <div class="normative section" id="s_expansion_control" typeof="bibo:Chapter" about="#s_expansion_control">
        <h3><span class="secno">10.2 </span>Vocabulary Expansion Control of RDFa Processors</h3>
        <p> Conforming RDFa processors are NOT required to provide vocabulary
          expansion. </p>
        <p> If an RDFa processor provides vocabulary expansion, it <em class="rfc2119" title="must not">must not</em> be
          performed by default. Instead, the processor <em class="rfc2119" title="must">must</em> provide an option, <code>vocab_expansion</code>,
          which, when used, instructs the RDFa processor to perform a vocabulary
          expansion before returning the output graph. </p>
        <p class="note"> Although vocabulary expansion is described in terms of
          a <a class="tref" title="vocabulary-graph" href="#T-vocabulary-graph">vocabulary graph</a> and RDFS entailment rules, processors
          are free to use any process which obtains equivalent results. </p>
        <div class="informative section" id="s_vocab_guidelines" typeof="bibo:Chapter" about="#s_vocab_guidelines">
          <h4><span class="secno">10.2.1 </span>Notes to RDFa Vocabulary Implementations and Publishing</h4><p><em>This section is non-normative.</em></p>
          <p>For RDFa Processors caching the relevant graphs retrieved via this
            mechanism is <em class="rfc2119" title="recommended">recommended</em>. Caching is usually based on HTTP response
            headers like expiration time, cache control, etc.</p>
          <p>For publishers of vocabularies, the URI for the vocabularies <em class="rfc2119" title="should">should</em>
            be dereferencable, and should return an RDF graph with the
            vocabulary description. This vocabulary description <em class="rfc2119" title="should">should</em> be
            available encoded in RDFa, and <em class="rfc2119" title="may">may</em> also be available in other RDF
            serialization syntaxes (using content negotiation to choose among
            the different formats). If possible, vocabulary descriptions <em class="rfc2119" title="should">should</em>
            include subproperty and subclass statements linking the vocabulary
            terms to other, well-known vocabularies. Finally, HTTP responses
            <em class="rfc2119" title="should">should</em> include fields usable for cache control, e.g., expiration
            date.</p>
        </div>
      </div>
    </div>
    <div class="appendix section" id="s_datatypes" typeof="bibo:Chapter" about="#s_datatypes">
      
<!-- OddPage -->
<h2><span class="secno">A. </span>CURIE Datatypes</h2>
      <p>In order to facilitate the use of CURIEs in markup languages, this
        specification defines some additional datatypes in the XHTML datatype
        space (<code>http://www.w3.org/1999/xhtml/datatypes/</code>). Markup
        languages that want to import these definitions can find them in the
        &quot;datatypes&quot; file for their schema grammar:</p>
      <ul>
        <li><a href="http://www.w3.org/MarkUp/DTD/xhtml-datatypes-1.mod">DTD
            xhtml-datatypes.mod</a></li>
        <li><a href="http://www.w3.org/MarkUp/SCHEMA/xhtml-datatypes-1.xsd">XML
            Schema xhtml-datatypes.xsd</a></li>
      </ul>
      <p>Specifically, the following datatypes are defined:</p>
      <dl>
        <dt><dfn id="dfn-curie">CURIE</dfn></dt>
        <dd>A single <a href="#P_curie">curie</a></dd>
        <dt><dfn id="dfn-curies">CURIEs</dfn></dt>
        <dd>A white space separated list of CURIEs</dd>
        <dt><dfn id="dfn-curieoriri">CURIEorIRI</dfn></dt>
        <dd>A <a class="datatype internalDFN" title="CURIE" href="#dfn-curie">CURIE</a> or a <a class="externalDFN" title="IRI">IRI</a></dd>
        <dt><dfn id="dfn-curieoriris">CURIEorIRIs</dfn></dt>
        <dd>A white space separated list of <a class="datatype internalDFN" title="CURIEorIRI" href="#dfn-curieoriri">CURIEorIRI</a>s</dd>
        <dt><dfn id="dfn-safecurie">SafeCURIE</dfn></dt>
        <dd>A single <a href="#P_safe_curie">safe_curie</a></dd>
        <dt><dfn id="dfn-safecurieorcurieoriri">SafeCURIEorCURIEorIRI</dfn></dt>
        <dd>A single <a class="datatype internalDFN" title="SafeCURIE" href="#dfn-safecurie">SafeCURIE</a> or <a class="datatype internalDFN" title="CURIEorIRI" href="#dfn-curieoriri">CURIEorIRI</a></dd>
        <dt><dfn id="dfn-safecurieorcurieoriris">SafeCURIEorCURIEorIRIs</dfn></dt>
        <dd>A white space separated list of <a class="datatype internalDFN" title="SafeCURIEorCURIEorIRI" href="#dfn-safecurieorcurieoriri">SafeCURIEorCURIEorIRI</a>s.</dd>
        <dt><dfn id="dfn-term">TERM</dfn></dt>
        <dd>A single <a href="#P_term">term</a></dd>
        <dt><dfn id="dfn-termorcurieorabsiri">TERMorCURIEorAbsIRI</dfn></dt>
        <dd>A <a class="datatype internalDFN" title="TERM" href="#dfn-term">TERM</a> or a <a class="datatype internalDFN" title="CURIEorIRI" href="#dfn-curieoriri">CURIEorIRI</a></dd>
        <dt><dfn id="dfn-termorcurieorabsiris">TERMorCURIEorAbsIRIs</dfn></dt>
        <dd>A white space separated list of <a class="datatype internalDFN" title="TERMorCURIEorAbsIRI" href="#dfn-termorcurieorabsiri">TERMorCURIEorAbsIRI</a>s</dd>
      </dl>
      <div class="informative section" id="xml-schema-definition" typeof="bibo:Chapter" about="#xml-schema-definition">
        <h3><span class="secno">A.1 </span>XML Schema Definition</h3><p><em>This section is non-normative.</em></p>
        <p>The following <i>informative</i> XML Schema definition for these
          datatypes is included as an example:</p>
        <pre class="example">&lt;?xml version=&quot;1.0&quot; encoding=&quot;UTF-8&quot;?&gt;
&lt;xs:schema
 xmlns:xs=&quot;http://www.w3.org/2001/XMLSchema&quot;
 xmlns=&quot;http://www.w3.org/1999/xhtml/datatypes/&quot;
 xmlns:xh11d=&quot;http://www.w3.org/1999/xhtml/datatypes/&quot;
 targetNamespace=&quot;http://www.w3.org/1999/xhtml/datatypes/&quot;
 elementFormDefault=&quot;qualified&quot;
&gt;
    &lt;xs:simpleType name=&quot;CURIE&quot;&gt;
        &lt;xs:restriction base=&quot;xs:string&quot;&gt;
            &lt;xs:pattern value=&quot;(([\i-[:]][\c-[:]]*)?:)?.+&quot; /&gt;
            &lt;xs:minLength value=&quot;1&quot;/&gt;
        &lt;/xs:restriction&gt;
    &lt;/xs:simpleType&gt; 

    &lt;xs:simpleType name=&quot;CURIEs&quot;&gt;
        &lt;xs:list itemType=&quot;xh11d:CURIE&quot;/&gt;
    &lt;/xs:simpleType&gt;

    &lt;xs:simpleType name=&quot;SafeCURIE&quot;&gt;
        &lt;xs:restriction base=&quot;xs:string&quot;&gt;
            &lt;xs:pattern value=&quot;\[(([\i-[:]][\c-[:]]*)?:)?.+\]&quot; /&gt;
            &lt;xs:minLength value=&quot;3&quot;/&gt;
        &lt;/xs:restriction&gt;
    &lt;/xs:simpleType&gt;

    &lt;xs:simpleType name=&quot;SafeCURIEs&quot;&gt;
        &lt;xs:list itemType=&quot;xh11d:SafeCURIE&quot;/&gt;
    &lt;/xs:simpleType&gt;

    &lt;xs:simpleType name=&quot;TERM&quot;&gt;
      &lt;xs:restriction base=&quot;xs:Name&quot;&gt;
        &lt;xs:pattern value=&quot;[\i-[:]][/\c-[:]]*&quot; /&gt;
      &lt;/xs:restriction&gt;
    &lt;/xs:simpleType&gt;
    

    &lt;xs:simpleType name=&quot;CURIEorIRI&quot;&gt;
        &lt;xs:union memberTypes=&quot;xh11d:CURIE xs:anyURI&quot; /&gt;
    &lt;/xs:simpleType&gt;

    &lt;xs:simpleType name=&quot;CURIEorIRIs&quot;&gt;
        &lt;xs:list itemType=&quot;xh11d:CURIEorIRI&quot;/&gt;
    &lt;/xs:simpleType&gt;

    &lt;xs:simpleType name=&quot;SafeCURIEorCURIEorIRI&quot;&gt;
        &lt;xs:union memberTypes=&quot;xh11d:SafeCURIE xh11d:CURIE xs:anyURI&quot; /&gt;
    &lt;/xs:simpleType&gt;

    &lt;xs:simpleType name=&quot;SafeCURIEorCURIEorIRIs&quot;&gt;
        &lt;xs:list itemType=&quot;xh11d:SafeCURIEorCURIEorIRI&quot;/&gt;
    &lt;/xs:simpleType&gt;

    &lt;xs:simpleType name='AbsIRI'&gt;
        &lt;xs:restriction base='xs:string'&gt;
            &lt;xs:pattern value=&quot;[\i-[:]][\c-[:]]+:.+&quot; /&gt;
        &lt;/xs:restriction&gt;
    &lt;/xs:simpleType&gt;

    &lt;xs:simpleType name=&quot;TERMorCURIEorAbsIRI&quot;&gt;
        &lt;xs:union memberTypes=&quot;xh11d:TERM xh11d:CURIE xh11d:AbsIRI&quot; /&gt;
    &lt;/xs:simpleType&gt;

    &lt;xs:simpleType name=&quot;TERMorCURIEorAbsIRIs&quot;&gt;
        &lt;xs:list itemType=&quot;xh11d:SafeCURIEorCURIEorAbsIRI&quot;/&gt;
    &lt;/xs:simpleType&gt;
&lt;/xs:schema&gt;</pre> </div>
      <div class="informative section" id="xml-dtd-definition" typeof="bibo:Chapter" about="#xml-dtd-definition">
        <h3><span class="secno">A.2 </span>XML DTD Definition</h3><p><em>This section is non-normative.</em></p>
        <p>The following <i>informative</i> XML DTD definition for these
          datatypes is included as an example:</p>
        <pre class="example">&lt;!ENTITY % CURIE.datatype &quot;CDATA&quot; &gt;
&lt;!ENTITY % CURIEs.datatype &quot;CDATA&quot; &gt;
&lt;!ENTITY % CURIEorIRI.datatype &quot;CDATA&quot; &gt;
&lt;!ENTITY % CURIEorIRIs.datatype &quot;CDATA&quot; &gt;
&lt;!ENTITY % SafeCURIEorCURIEorIRI.datatype &quot;CDATA&quot; &gt;
&lt;!ENTITY % SafeCURIEorCURIEorIRIs.datatype &quot;CDATA&quot; &gt;
&lt;!ENTITY % TERMorCURIEorAbsIRI.datatype &quot;CDATA&quot; &gt;
&lt;!ENTITY % TERMorCURIEorAbsIRIs.datatype &quot;CDATA&quot; &gt;</pre> </div>
    </div>
    <div class="normative section" id="vocabulary" typeof="bibo:Chapter" about="#vocabulary">
      
<!-- OddPage -->
<h2><span class="secno">B. </span>The RDFa Vocabulary</h2>
      <p>The RDFa Vocabulary has three roles: it contains the predicates to
        define the terms and prefixes in <a class="tref" title="initial-context" href="#T-initial-context">initial context</a>
        documents, it contains the classes and predicates for the messages that
        a <a class="tref" title="processor-graph" href="#T-processor-graph">processor graph</a> may contain and, finally, it contains
        the predicate necessary for vocabulary processing. The IRI of the
        vocabulary is <code>http://www.w3.org/ns/rdfa#</code>; the usual prefix
        used in this document is <code>rdfa</code>.</p>
      <p>This vocabulary specification is available in <a href="http://www.w3.org/ns/rdfa.html">XHTML+RDFa

          1.1</a>, <a href="http://www.w3.org/ns/rdfa.ttl">Turtle</a>, and in <a href="http://www.w3.org/ns/rdfa.rdf">RDF/XML</a>
        formats.</p>
      <div class="normative section" id="term-prefix-definitions-vocabulary" typeof="bibo:Chapter" about="#term-prefix-definitions-vocabulary">
        <h3><span class="secno">B.1 </span>Term and Prefix Assignments</h3>
        <p>The RDFa Vocabulary includes the following triples (shown here in
          Turtle [<cite><a class="bibref" rel="biblioentry" href="#bib-TURTLE">TURTLE</a></cite>] format): </p>
        <pre class="example">@prefix dc:      &lt;http://purl.org/dc/terms/&gt; .
@prefix owl:     &lt;http://www.w3.org/2002/07/owl#&gt; .
@prefix rdf:     &lt;http://www.w3.org/1999/02/22-rdf-syntax-ns#&gt; .
@prefix rdfs:    &lt;http://www.w3.org/2000/01/rdf-schema#&gt; .
@prefix rdfa:    &lt;http://www.w3.org/ns/rdfa#&gt; .
@prefix foaf:    &lt;http://xmlns.com/foaf/0.1/&gt; .

&lt;http://www.w3.org/ns/rdfa#&gt; a owl:Ontology .

rdfa:PrefixOrTermMapping a rdfs:Class, owl:Class ;
    dc:description &quot;is the top level class for prefix or term mappings&quot; .
    
rdfa:PrefixMapping dc:description &quot;is the class for prefix mappings&quot; .
    rdfs:subClassOf rdfa:PrefixOrTermMapping .
    
rdfa:TermMapping dc:description &quot;is the class for term mappings&quot; .
    rdfs:subClassOf rdfa:PrefixOrTermMapping .

rdfa:prefix a rdf:Property, owl:DatatypeProperty ;
     rdfs:domain rdfa:PrefixMapping ;
     dc:description &quot;defines a prefix mapping for an IRI; the value is supposed to be a NMTOKEN&quot; . 

rdfa:term a rdf:Property, owl:DatatypeProperty ;
     rdfs:domain rdfa:TermMapping ;
     dc:description &quot;defines a term mapping for an IRI; the value is supposed to be a NMTOKEN&quot; . 

rdfa:uri a rdf:Property, owl:DatatypeProperty ;
     rdfs:domain rdfa:PrefixOrTermMapping ;
     dc:description &quot;&quot;&quot;defines the IRI for either a prefix or a term mapping;
        the value is supposed to be an absolute IRI&quot;&quot;&quot; . 

rdfa:vocabulary a rdf:Property, owl:DatatypeProperty ;
     dc:description &quot;&quot;&quot;defines an IRI to be used as a default vocabulary;
        the value is can be any string; for documentation purposes it is advised to use
        the string ‘true’ or ‘True’.&quot;&quot;&quot; . </pre>
        <p>These predicates can be used to define the <a class="tref" title="initial-context" href="#T-initial-context">initial context</a>
          for a given Host Language.</p>
        <p>These predicates are used to 'pair' IRI strings and their usage in
          the form of a prefix and/or a term as part of, for example, a blank
          node. An example can be as follows:</p>
        <pre class="example">[] rdfa:uri     &quot;http://xmlns.com/foaf/0.1/name&quot; ;
   rdfa:prefix  &quot;foaf&quot; . </pre>
        <p>which defines a prefix for the foaf IRI.</p>
      </div>
      <div class="normative section" id="processor-graph-reporting" typeof="bibo:Chapter" about="#processor-graph-reporting">
        <h3><span class="secno">B.2 </span>Processor Graph Reporting</h3>
        <p>The Vocabulary includes the following term definitions (shown here in
          Turtle [<cite><a class="bibref" rel="biblioentry" href="#bib-TURTLE">TURTLE</a></cite>] format): </p>
        <pre class="example">@prefix dc:      &lt;http://purl.org/dc/terms/&gt; .
@prefix owl:     &lt;http://www.w3.org/2002/07/owl#&gt; .
@prefix rdf:     &lt;http://www.w3.org/1999/02/22-rdf-syntax-ns#&gt; .
@prefix rdfs:    &lt;http://www.w3.org/2000/01/rdf-schema#&gt; .
@prefix rdfa:    &lt;http://www.w3.org/ns/rdfa#&gt; .

rdfa:PGClass a rdfs:Class, owl:Class;
    dc:description &quot;is the top level class of the hierarchy&quot; .

rdfa:Error dcterms:description &quot;is the class for all error conditions&quot;;
    rdfs:subClassOf rdfa:PGClass .

rdfa:Warning dcterms:description &quot;is the class for all warnings&quot;;
    rdfs:subClassOf rdfa:PGClass .

rdfa:Info dcterms:description &quot;is the class for all informations&quot;;
    rdfs:subClassOf rdfa:PGClass .

rdfa:DocumentError dc:description &quot;error condition; to be used when the document
    fails to be fully processed as a result of non-conformant host language markup&quot;;
    rdfs:subClassOf rdfa:Error .

rdfa:VocabReferenceError dc:description &quot;warning; to be used
    when the value of a @vocab attribute cannot be dereferenced, hence the vocabulary expansion
    cannot be completed.&quot;;
    rdfs:subClassOf rdfa:Warning .

rdfa:UnresolvedTerm dc:description &quot;warning; to be used when a Term fails to be resolved&quot;;
    rdfs:subClassOf rdfa:Warning .

rdfa:UnresolvedCURIE dc:description &quot;warning; to be used when a CURIE prefix
    fails to be resolved&quot;;
    rdfs:subClassOf rdfa:Warning .
    
rdfa:context a owl:ObjectProperty, rdf:Property;
    dc:description &quot;provides extra context for the error, e.g., http response,
    an XPointer/XPath information, or simply the IRI that created the error&quot;;
    rdfs:domain rdfa:PGClass .</pre> </div>
      <div class="normative section" id="vocabulary-relationship" typeof="bibo:Chapter" about="#vocabulary-relationship">
        <h3><span class="secno">B.3 </span>Term for vocabulary expansion</h3>
        <p>The Vocabulary includes the following term definitions (shown here in
          Turtle [<cite><a class="bibref" rel="biblioentry" href="#bib-TURTLE">TURTLE</a></cite>] format): </p>
        <pre class="example">@prefix dc:      &lt;http://purl.org/dc/terms/&gt; .
@prefix owl:     &lt;http://www.w3.org/2002/07/owl#&gt; .
@prefix rdf:     &lt;http://www.w3.org/1999/02/22-rdf-syntax-ns#&gt; .
@prefix rdfa:    &lt;http://www.w3.org/ns/rdfa#&gt; .

rdfa:usesVocabulary a owl:ObjectProperty, rdf:Property;
    dc:description &quot;provides a relationship between the host document and a vocabulary
    defined using the @vocab facility of RDFa1.1&quot; .</pre> </div>
      <div class="informative section" id="a_history" typeof="bibo:Chapter" about="#a_history">
        <h3><span class="secno">B.4 </span>Changes</h3><p><em>This section is non-normative.</em></p>
        <div id="major-differences-with-rdfa-syntax-1.0" typeof="bibo:Chapter" about="#major-differences-with-rdfa-syntax-1.0" class="section">
          <h4><span class="secno">B.4.1 </span>Major differences with RDFa Syntax 1.0</h4>
          <p>This specification introduces a number of new features, and extends
            the behavior of some features from the previous version. The
            following summary may be helpful to RDFa Processor developers, but
            is <em>not</em> meant to be comprehensive.</p>
          <ul>
            <li>Specific rules about XHTML have been moved into a companion
              specification: [<cite><a class="bibref" rel="biblioentry" href="#bib-XHTML-RDFA">XHTML-RDFA</a></cite>].</li>
            <li>Prefix mappings can now be declared using <a class="aref" href="#A-prefix" title="prefix">@prefix</a>
              in addition to <span class="aref">@xmlns</span>. The usage of <span class="aref">@xmlns</span>
              has been deprecated.</li>
            <li>Prefix names are now required be be converted to lower-case when
              the mapping is defined. Prefixes are checked in a case-insensitive
              manner during CURIE expansion.</li>
            <li>You can now use an Absolute IRI everywhere you could previously
              only use a CURIE (e.g., in the value of <a class="aref" href="#A-datatype" title="datatype">@datatype</a>).</li>
            <li>There is now a concept of a <a class="tref" title="term" href="#T-term">term</a>. This concept has
              replaced the concept of a 'reserved word'. It is possible now to
              use a 'term' in most places where you could previously only use a
              CURIE.</li>
            <li>You can define a default prefix mapping (via <a class="aref" href="#A-vocab" title="vocab">@vocab</a>)
              that will be used on undefined terms.</li>
            <li>When a triple would include an object literal, and there is no
              explicit datatype attribute, the object literal will now be a
              'plain literal'. In version 1.0 it would have been an
              'XMLLiteral'.</li>
            <li>The <a class="aref" href="#A-inlist" title="inlist">@inlist</a> attribute can be used to instruct the
              processor to generate RDF lists with the resources rather than
              simple triples.</li>
            <li>The effect of <a class="aref" href="#A-src" title="src">@src</a> is now identical to <a class="aref" href="#A-href" title="href">@href</a>
              rather than <a class="aref" href="#A-about" title="about">@about</a> like in version 1.0. </li>
          </ul>
          <p>While this specification strives to be as backward compatible as
            possible with [<cite><a class="bibref" rel="biblioentry" href="#bib-RDFA-SYNTAX">RDFA-SYNTAX</a></cite>], the changes above mean that there are
            some circumstances where it is possible for different RDF triples to
            be output for the same document when processed by an RDFa 1.0
            processor vs. an RDFa 1.1 processor. In order to minimize these
            differences, a document author can do the following:</p>
          <ul>
            <li>Use the XHTML+RDFa 1.0 document type as defined in
              [<cite><a class="bibref" rel="biblioentry" href="#bib-RDFA-SYNTAX">RDFA-SYNTAX</a></cite>].</li>
            <li>Place a <span class="aref">@version</span> attribute with the
              value <code>XHTML+RDFa 1.0</code> on the <code>html</code>
              element.</li>
            <li>If there are places in the document where an object literal <em class="rfc2119" title="must">must</em>
              be an XMLLiteral, use <code>datatype='rdf:XMLLiteral'</code>.</li>
            <li>If there are places in the document where an object literal <em class="rfc2119" title="must">must</em>
              be a plain literal, use <code>datatype=''</code>.</li>
            <li>If there are places in the document where <a class="aref" href="#A-src" title="src">@src</a> is
              used, add an <a class="aref" href="#A-about" title="about">@about</a> (unless already present) with the
              same URI.</li>
          </ul>
          <p>When producing XHTML+RDFa 1.1 documents, it is possible to reduce
            the incompatibilities with RDFa 1.0 conforming processors by doing
            the following:</p>
          <ul>
            <li>DO NOT use the <a class="aref" href="#A-vocab" title="vocab">@vocab</a> feature.</li>
            <li>DO NOT rely upon host language defaults for IRI mappings.</li>
            <li>DO NOT use absolute IRIs in place of CURIEs.</li>
            <li>Use <span class="aref">@xmlns</span> AND <a class="aref" href="#A-prefix" title="prefix">@prefix</a>
              when declaring prefix mappings.</li>
            <li>DO NOT use TERMs on <a class="aref" href="#A-datatype" title="datatype">@datatype</a>, <a class="aref" href="#A-property" title="property">@property</a>,
              or <a class="aref" href="#A-typeof" title="typeof">@typeof</a>.</li>
            <li>When using TERMs in <a class="aref" href="#A-rel" title="rel">@rel</a> and <a class="aref" href="#A-rev" title="rev">@rev</a>,
              only use ones defined in [<cite><a class="bibref" rel="biblioentry" href="#bib-RDFA-SYNTAX">RDFA-SYNTAX</a></cite>].</li>
            <li>Place a <span class="aref">version</span> attribute with the
              value <code>XHTML+RDFa 1.0</code> on the <code>html</code>
              element.</li>
            <li>If there are places in the document where an object literal <em class="rfc2119" title="must">must</em>
              be an XMLLiteral, use <code>datatype='rdf:XMLLiteral'</code>.</li>
            <li>If there are places in the document where an object literal <em class="rfc2119" title="must">must</em>
              be a plain literal, use <code>datatype=''</code>.</li>
            <li>If there are places in the document where <a class="aref" href="#A-src" title="src">@src</a> is
              used, add an <a class="aref" href="#A-about" title="about">@about</a> (unless already present) with the
              same URI.</li>
          </ul>
        </div>
      </div>
    </div>
    <div class="informative section" id="a_acks" typeof="bibo:Chapter" about="#a_acks">
      
<!-- OddPage -->
<h2><span class="secno">C. </span>Acknowledgments</h2><p><em>This section is non-normative.</em></p>
      <p>At the time of publication, the active members of the RDFa Working
        Group were:</p>
      <ul>
        <li>Ben Adida, Creative Commons (Chair)</li>
        <li>Benjamin Adrian, German Research Center for Artificial Intelligence
          (DFKI) Gmbh</li>
        <li>Mark Birbeck, webBackplane.com (Invited Expert)</li>
        <li>Stéphane Corlosquet, Massachusetts General Hospital</li>
        <li>Markus Gylling, DAISY Consortium</li>
        <li>Ivan Herman, <acronym title="World Wide Web Consortium">W3C</acronym></li>
        <li>Toby Inkster (Invited Expert)</li>
        <li>Gregg Kellogg (Invited Expert)</li>
        <li>Niklas Lindström (Invited Expert)</li>
        <li>Shane McCarron, Applied Testing and Technology, Inc. (Invited
          Expert)</li>
        <li>Knud Möller, DERI Galway at the National University of Ireland</li>
        <li>John O'Donovan, British Broadcasting Corporation</li>
        <li>Steven Pemberton, Centre for Mathematics and Computer Science (CWI)</li>
        <li>Nathan Rixham (Invited Expert)</li>
        <li>Manu Sporny, Digital Bazaar (Chair, Invited Expert)</li>
        <li>Robert Weir, IBM Corporation</li>
      </ul>
    </div>
  

<div id="references" class="appendix section" typeof="bibo:Chapter" about="#references">
<!-- OddPage -->
<h2><span class="secno">D. </span>References</h2><div id="normative-references" typeof="bibo:Chapter" about="#normative-references" class="section"><h3><span class="secno">D.1 </span>Normative references</h3><dl class="bibliography" about=""><dt id="bib-OWL2-OVERVIEW">[OWL2-OVERVIEW]</dt><dd rel="dcterms:requires">W3C OWL Working Group. <a href="http://www.w3.org/TR/2009/REC-owl2-overview-20091027/"><cite>OWL 2 Web Ontology Language: Overview.</cite></a> 27 October 2009. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2009/REC-owl2-overview-20091027/">http://www.w3.org/TR/2009/REC-owl2-overview-20091027/</a> 
</dd><dt id="bib-OWL2-PROFILES">[OWL2-PROFILES]</dt><dd rel="dcterms:requires">Boris Motik; Bernardo Cuenca Grau; Ian Horrocks; Zhe Wu; Achille Fokoue; Carsten Lutz. <a href="http://www.w3.org/TR/2009/REC-owl2-profiles-20091027/"><cite>OWL 2 Web Ontology Language:Profiles.</cite></a> 27 October 2009. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2009/REC-owl2-profiles-20091027/">http://www.w3.org/TR/2009/REC-owl2-profiles-20091027/</a> 
</dd><dt id="bib-OWL2-RDF-BASED-SEMANTICS">[OWL2-RDF-BASED-SEMANTICS]</dt><dd rel="dcterms:requires">Michael Schneider. <a href="http://www.w3.org/TR/2009/REC-owl2-rdf-based-semantics-20091027/"><cite>OWL 2 Web Ontology Language:RDF-Based Semantics.</cite></a> 27 October 2009. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2009/REC-owl2-rdf-based-semantics-20091027/">http://www.w3.org/TR/2009/REC-owl2-rdf-based-semantics-20091027/</a> 
</dd><dt id="bib-RDF-MT">[RDF-MT]</dt><dd rel="dcterms:requires">Patrick Hayes. <a href="http://www.w3.org/TR/2004/REC-rdf-mt-20040210"><cite>RDF Semantics.</cite></a> 10 February 2004. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2004/REC-rdf-mt-20040210">http://www.w3.org/TR/2004/REC-rdf-mt-20040210</a> 
</dd><dt id="bib-RDF-SYNTAX-GRAMMAR">[RDF-SYNTAX-GRAMMAR]</dt><dd rel="dcterms:requires">Dave Beckett. <a href="http://www.w3.org/TR/2004/REC-rdf-syntax-grammar-20040210"><cite>RDF/XML Syntax Specification (Revised).</cite></a> 10 February 2004. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2004/REC-rdf-syntax-grammar-20040210">http://www.w3.org/TR/2004/REC-rdf-syntax-grammar-20040210</a> 
</dd><dt id="bib-RFC2119">[RFC2119]</dt><dd rel="dcterms:requires">S. Bradner. <a href="http://www.ietf.org/rfc/rfc2119.txt"><cite>Key words for use in RFCs to Indicate Requirement Levels.</cite></a> March 1997. Internet RFC 2119.  URL: <a href="http://www.ietf.org/rfc/rfc2119.txt">http://www.ietf.org/rfc/rfc2119.txt</a> 
</dd><dt id="bib-RFC3987">[RFC3987]</dt><dd rel="dcterms:requires">M. Dürst; M. Suignard. <a href="http://www.ietf.org/rfc/rfc3987.txt"><cite>Internationalized Resource Identifiers (IRIs).</cite></a> January 2005. Internet RFC 3987. URL: <a href="http://www.ietf.org/rfc/rfc3987.txt">http://www.ietf.org/rfc/rfc3987.txt</a> 
</dd><dt id="bib-TURTLE">[TURTLE]</dt><dd rel="dcterms:requires">David Beckett, Tim Berners-Lee. <a href="http://www.w3.org/TeamSubmission/turtle/"><cite>Turtle: Terse RDF Triple Language.</cite></a> January 2008. W3C Team Submission. URL: <a href="http://www.w3.org/TeamSubmission/turtle/">http://www.w3.org/TeamSubmission/turtle/</a> 
</dd><dt id="bib-XHTML-RDFA">[XHTML-RDFA]</dt><dd rel="dcterms:requires">Shane McCarron; et. al. <a href="http://www.w3.org/TR/2011/WD-xhtml-rdfa-20111215"><cite>XHTML+RDFa 1.1.</cite></a> 15 December 2011. W3C Working Draft. URL: <a href="http://www.w3.org/TR/2011/WD-xhtml-rdfa-20111215">http://www.w3.org/TR/2011/WD-xhtml-rdfa-20111215</a> 
</dd><dt id="bib-XML-NAMES">[XML-NAMES]</dt><dd rel="dcterms:requires">Richard Tobin; et al. <a href="http://www.w3.org/TR/2009/REC-xml-names-20091208/"><cite>Namespaces in XML 1.0 (Third Edition).</cite></a> 8 December 2009. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2009/REC-xml-names-20091208/">http://www.w3.org/TR/2009/REC-xml-names-20091208/</a> 
</dd><dt id="bib-XML10-4e">[XML10-4e]</dt><dd rel="dcterms:requires">C. M. Sperberg-McQueen; et al. <a href="http://www.w3.org/TR/2006/REC-xml-20060816/"><cite>Extensible Markup Language (XML) 1.0 (Fourth Edition).</cite></a> 16 August 2006. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2006/REC-xml-20060816/">http://www.w3.org/TR/2006/REC-xml-20060816/</a> 
</dd><dt id="bib-XMLSCHEMA-2">[XMLSCHEMA-2]</dt><dd rel="dcterms:requires">Paul V. Biron; Ashok Malhotra. <a href="http://www.w3.org/TR/2004/REC-xmlschema-2-20041028/"><cite>XML Schema Part 2: Datatypes Second Edition.</cite></a> 28 October 2004. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2004/REC-xmlschema-2-20041028/">http://www.w3.org/TR/2004/REC-xmlschema-2-20041028/</a> 
</dd></dl></div><div id="informative-references" typeof="bibo:Chapter" about="#informative-references" class="section"><h3><span class="secno">D.2 </span>Informative references</h3><dl class="bibliography" about=""><dt id="bib-HTML401">[HTML401]</dt><dd rel="dcterms:references">David Raggett; Ian Jacobs; Arnaud Le Hors. <a href="http://www.w3.org/TR/1999/REC-html401-19991224"><cite>HTML 4.01 Specification.</cite></a> 24 December 1999. W3C Recommendation. URL: <a href="http://www.w3.org/TR/1999/REC-html401-19991224">http://www.w3.org/TR/1999/REC-html401-19991224</a> 
</dd><dt id="bib-MICROFORMATS">[MICROFORMATS]</dt><dd rel="dcterms:references"><a href="http://microformats.org"><cite>Microformats</cite></a>. URL: <a href="http://microformats.org">http://microformats.org</a> 
</dd><dt id="bib-QNAMES">[QNAMES]</dt><dd rel="dcterms:references">N. Walsh. <a href="http://www.w3.org/2001/tag/doc/qnameids-2004-03-17"><cite>Using Qualified Names (QNames) as Identifiers in XML Content</cite></a> 17 March, 2004. TAG Finding. URL: <a href="http://www.w3.org/2001/tag/doc/qnameids-2004-03-17">http://www.w3.org/2001/tag/doc/qnameids-2004-03-17</a> 
</dd><dt id="bib-RDF-CONCEPTS">[RDF-CONCEPTS]</dt><dd rel="dcterms:references">Graham Klyne; Jeremy J. Carroll. <a href="http://www.w3.org/TR/2004/REC-rdf-concepts-20040210"><cite>Resource Description Framework (RDF): Concepts and Abstract Syntax.</cite></a> 10 February 2004. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2004/REC-rdf-concepts-20040210">http://www.w3.org/TR/2004/REC-rdf-concepts-20040210</a> 
</dd><dt id="bib-RDF-PRIMER">[RDF-PRIMER]</dt><dd rel="dcterms:references">Frank Manola; Eric Miller. <a href="http://www.w3.org/TR/2004/REC-rdf-primer-20040210/"><cite>RDF Primer.</cite></a> 10 February 2004. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2004/REC-rdf-primer-20040210/">http://www.w3.org/TR/2004/REC-rdf-primer-20040210/</a> 
</dd><dt id="bib-RDF-SYNTAX">[RDF-SYNTAX]</dt><dd rel="dcterms:references">Ora Lassila; Ralph R. Swick. <a href="http://www.w3.org/TR/1999/REC-rdf-syntax-19990222"><cite>Resource Description Framework (RDF) Model and Syntax Specification.</cite></a> 22 February 1999. W3C Recommendation. URL: <a href="http://www.w3.org/TR/1999/REC-rdf-syntax-19990222">http://www.w3.org/TR/1999/REC-rdf-syntax-19990222</a> 
</dd><dt id="bib-RDF-TESTCASES">[RDF-TESTCASES]</dt><dd rel="dcterms:references">Jan Grant; Dave Beckett. <a href="http://www.w3.org/TR/2004/REC-rdf-testcases-20040210"><cite>RDF Test Cases.</cite></a> 10 February 2004. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2004/REC-rdf-testcases-20040210">http://www.w3.org/TR/2004/REC-rdf-testcases-20040210</a> 
</dd><dt id="bib-RDFA-PRIMER">[RDFA-PRIMER]</dt><dd rel="dcterms:references">Mark Birbeck; Ben Adida. <a href="http://www.w3.org/TR/2008/NOTE-xhtml-rdfa-primer-20081014"><cite>RDFa Primer.</cite></a> 14 October 2008. W3C Note. URL: <a href="http://www.w3.org/TR/2008/NOTE-xhtml-rdfa-primer-20081014">http://www.w3.org/TR/2008/NOTE-xhtml-rdfa-primer-20081014</a> 
</dd><dt id="bib-RDFA-SYNTAX">[RDFA-SYNTAX]</dt><dd rel="dcterms:references">Ben Adida, et al. <a href="http://www.w3.org/TR/2008/REC-rdfa-syntax-20081014"><cite>RDFa in XHTML: Syntax and Processing.</cite></a> 14 October 2008. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2008/REC-rdfa-syntax-20081014">http://www.w3.org/TR/2008/REC-rdfa-syntax-20081014</a> 
</dd><dt id="bib-RELAXNG-SCHEMA">[RELAXNG-SCHEMA]</dt><dd rel="dcterms:references"><a href="http://standards.iso.org/ittf/PubliclyAvailableStandards/c052348_ISO_IEC_19757-2_2008(E).zip"><cite>Information technology -- Document Schema Definition Language (DSDL) -- Part 2: Regular-grammar-based validation -- RELAX NG</cite></a>. ISO/IEC 19757-2:2008. URL: <a href="http://standards.iso.org/ittf/PubliclyAvailableStandards/c052348_ISO_IEC_19757-2_2008(E).zip">http://standards.iso.org/ittf/PubliclyAvailableStandards/c052348_ISO_IEC_19757-2_2008(E).zip</a>
</dd><dt id="bib-RFC2854">[RFC2854]</dt><dd rel="dcterms:references">D. Connolly; L. Masinter. <a href="http://www.rfc-editor.org/rfc/rfc2854.txt"><cite>The 'text/html' Media Type.</cite></a> June 2000. Internet RFC 2854. URL: <a href="http://www.rfc-editor.org/rfc/rfc2854.txt">http://www.rfc-editor.org/rfc/rfc2854.txt</a> 
</dd><dt id="bib-RFC3023">[RFC3023]</dt><dd rel="dcterms:references">M. Murata; S. St.Laurent; D. Kohn. <a href="http://www.ietf.org/rfc/rfc3023.txt"><cite>XML Media Types</cite></a> January 2001. Internet RFC 3023. URL: <a href="http://www.ietf.org/rfc/rfc3023.txt">http://www.ietf.org/rfc/rfc3023.txt</a> 
</dd><dt id="bib-RFC3986">[RFC3986]</dt><dd rel="dcterms:references">T. Berners-Lee; R. Fielding; L. Masinter. <a href="http://www.ietf.org/rfc/rfc3986.txt"><cite>Uniform Resource Identifier (URI): Generic Syntax.</cite></a> January 2005. Internet RFC 3986. URL: <a href="http://www.ietf.org/rfc/rfc3986.txt">http://www.ietf.org/rfc/rfc3986.txt</a> 
</dd><dt id="bib-SAX">[SAX]</dt><dd rel="dcterms:references">D. Megginson, et al. <a href="http://www.megginson.com/downloads/SAX/"><cite>SAX: The Simple API for XML</cite></a>. May 1998. URL: <a href="http://www.megginson.com/downloads/SAX/"> http://www.megginson.com/downloads/SAX/</a>
</dd><dt id="bib-WEBARCH">[WEBARCH]</dt><dd rel="dcterms:references">Norman Walsh; Ian Jacobs. <a href="http://www.w3.org/TR/2004/REC-webarch-20041215/"><cite>Architecture of the World Wide Web, Volume One.</cite></a> 15 December 2004. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2004/REC-webarch-20041215/">http://www.w3.org/TR/2004/REC-webarch-20041215/</a> 
</dd><dt id="bib-XHTML11">[XHTML11]</dt><dd rel="dcterms:references">Murray Altheim; Shane McCarron. <a href="http://www.w3.org/TR/2001/REC-xhtml11-20010531"><cite>XHTML™ 1.1 - Module-based XHTML.</cite></a> 31 May 2001. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2001/REC-xhtml11-20010531">http://www.w3.org/TR/2001/REC-xhtml11-20010531</a> 
</dd><dt id="bib-XML-EXC-C14N">[XML-EXC-C14N]</dt><dd rel="dcterms:references">Donald E. Eastlake 3rd; Joseph Reagle; John Boyer. <a href="http://www.w3.org/TR/2002/REC-xml-exc-c14n-20020718/"><cite>Exclusive XML Canonicalization Version 1.0.</cite></a> 18 July 2002. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2002/REC-xml-exc-c14n-20020718/">http://www.w3.org/TR/2002/REC-xml-exc-c14n-20020718/</a> 
</dd><dt id="bib-XML10">[XML10]</dt><dd rel="dcterms:references">C. M. Sperberg-McQueen; et al. <a href="http://www.w3.org/TR/2008/REC-xml-20081126/"><cite>Extensible Markup Language (XML) 1.0 (Fifth Edition).</cite></a> 26 November 2008. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2008/REC-xml-20081126/">http://www.w3.org/TR/2008/REC-xml-20081126/</a> 
</dd><dt id="bib-XMLSCHEMA-1">[XMLSCHEMA-1]</dt><dd rel="dcterms:references">Henry S. Thompson; et al. <a href="http://www.w3.org/TR/2004/REC-xmlschema-1-20041028/"><cite>XML Schema Part 1: Structures Second Edition.</cite></a> 28 October 2004. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2004/REC-xmlschema-1-20041028/">http://www.w3.org/TR/2004/REC-xmlschema-1-20041028/</a> 
</dd></dl></div></div></body></html>