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Tannaka–Krein duality

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25: 1553:. Tannaka–Krein philosophy suggests that braided monoidal categories arising from conformal field theory can also be obtained from quantum groups, and in a series of papers, Kazhdan and Lusztig proved that it was indeed so. On the other hand, braided monoidal categories arising from certain quantum groups were applied by Reshetikhin and Turaev to construction of new invariants of knots. 1549:. It turned out that a good duality theory of Tannaka–Krein type also exists in this case and plays an important role in the theory of quantum groups by providing a natural setting in which both the quantum groups and their representations can be studied. Shortly afterwards different examples of braided monoidal categories were found in 1410:
Let Π be a category of finite-dimensional vector spaces, endowed with operations of tensor product and involution. The following conditions are necessary and sufficient in order for Π to be a dual object to a compact group
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in general fail to form a group, or even a monoid, because a tensor product of irreducible representations is not necessarily irreducible. It turns out that one needs to consider the set
1303: 195:, allowing one to recover the group from its category of representations. Moreover, they in effect completely characterize all categories that can arise from a group in this fashion. 1399: 1109: 1469: 877: 1336: 985: 815: 686: 592: 1191: 906: 276: 1156: 835: 447: 715: 384: 340: 1129: 1437: 1537:. One of the main approaches to the study of a quantum group proceeds through its finite-dimensional representations, which form a category akin to the 1570: 1609: 1594: 89: 61: 497: 42: 68: 1208: 1840: 75: 1816: 597: 720: 57: 346:, where the product is the usual tensor product of representations, and the dual object is given by the operation of the 911: 452: 306: 108: 396: 1550: 1275: 1194: 46: 347: 1365: 1081: 1835: 82: 211:. A generalization of Tannaka–Krein theory provides the natural framework for studying representations of 1850: 1622: 1538: 1442: 840: 173: 1845: 1308: 295: 952: 787: 653: 1855: 1546: 1714: 565: 1643: 1067: 1046: 1161: 1407:
answers the following question: which categories can arise as a dual object to a compact group?
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Durkdević, Mićok (December 1996). "Quantum principal bundles and Tannaka-Krein duality theory".
1709: 1134: 1053: 387: 298: 279: 207:. Meanwhile, the original theory of Tannaka and Krein continued to be developed and refined by 196: 137: 1358:
gives rise to a tensor-preserving self-conjugate natural transformation via multiplication by
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Interest in Tannaka–Krein duality theory was reawakened in the 1980s with the discovery of
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Duality theorems of Tannaka and Krein describe the converse passage from the category Π(
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later showed that by a similar process, Tannaka duality can be extended to the case of
145: 1723: 180:) with some additional structure, formed by the finite-dimensional representations of 1812: 1780: 1775: 1732: 1589:. Such subcategories of compact group unitary representations on Hilbert spaces are: 1034: 777: 343: 291: 287: 133: 1804: 1770: 1752: 1719: 1660: 1566: 220: 1793: 1578: 244: 236: 200: 1038: 224: 212: 165: 153: 1641:
Doplicher, S.; Roberts, J. (1989). "A new duality theory for compact groups".
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to be noncommutative, the most direct analogue of the character group is the
169: 157: 130: 1784: 1534: 1505:) is either one-dimensional (when they are isomorphic) or is equal to zero. 1049: 1757: 1582: 231:
The idea of Tannaka–Krein duality: category of representations of a group
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of all tensor-preserving, self-conjugate natural transformations of
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and satisfies the conditions of compatibility with tensor products,
24: 1530: 552:{\displaystyle \varphi (T\otimes U)=\varphi (T)\otimes \varphi (U)} 391: 1401:. Tannaka's theorem then says that this map is an isomorphism. 1509:
If all these conditions are satisfied then the category Π = Π(
164:. In contrast to the case of commutative groups considered by 1257:{\displaystyle \tau _{V\otimes W}=\tau _{V}\otimes \tau _{W}} 342:
of all finite-dimensional representations, and treat it as a
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are two minimal objects then the space of homomorphisms Hom
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if it is the identity map on the trivial representation of
1803:, Lecture Notes in Mathematics, vol. 1488, Springer, 1475:
of Π (which will necessarily be unique up to isomorphism).
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where the bar denotes complex conjugation. Then the set
1205:, and if it preserves tensor products in the sense that 1070:
topology possible such that each of the projections End(
1794:"An introduction to Tannaka duality and quantum groups" 1482:
of Π can be decomposed into a sum of minimal objects.
1445: 1425: 1368: 1311: 1278: 1211: 1164: 1137: 1117: 1084: 955: 914: 885: 843: 823: 790: 723: 694: 656: 643:{\displaystyle f\circ \varphi (T)=\varphi (U)\circ f} 600: 568: 500: 455: 435: 429:
to itself. In other words, it is a non-zero function
399: 363: 319: 252: 769:{\displaystyle \varphi \psi (T)=\varphi (T)\psi (T)} 1608:, such that the C*-algebra of endomorphisms of the 305:. The analogue of the product of characters is the 152:topological groups, to groups that are compact but 49:. Unsourced material may be challenged and removed. 1463: 1431: 1393: 1330: 1297: 1256: 1185: 1150: 1123: 1103: 979: 941: 900: 871: 829: 809: 768: 709: 680: 642: 586: 551: 482: 441: 421: 378: 334: 270: 1827: 1640: 1362:on each representation, and hence one has a map 990: 1737:Proceedings of the National Academy of Sciences 1346:), which is in fact a (compact) group whenever 942:{\displaystyle T\in \operatorname {Ob} \Pi (G)} 483:{\displaystyle T\in \operatorname {Ob} \Pi (G)} 239:commutative groups, the dual object to a group 16:Duality between a group and its representations 422:{\displaystyle \operatorname {id} _{\Pi (G)}} 215:, and is currently being extended to quantum 1556: 987:thus becomes a compact (topological) group. 866: 844: 804: 791: 1791: 1517:is the group of the representations of Π. 1197:. We say that a natural transformation is 309:. However, irreducible representations of 1774: 1756: 1733:"Quantum groups with invariant integrals" 1730: 1713: 1695: 1681: 1298:{\displaystyle {\overline {\tau }}=\tau } 109:Learn how and when to remove this message 1005:from its category of representations Π( 688:of all representations of the category 1828: 1394:{\displaystyle G\to {\mathcal {T}}(G)} 1104:{\displaystyle \tau \mapsto \tau _{V}} 278:which consists of its one-dimensional 168:, the notion dual to a noncommutative 129:theory concerns the interaction of a 1350:is a (compact) group. Every element 47:adding citations to reliable sources 18: 1464:{\displaystyle I\otimes A\approx A} 872:{\displaystyle \{\varphi _{a}(T)\}} 717:can be endowed with multiplication 13: 1377: 1314: 1171: 998:provides a way to reconstruct the 962: 956: 927: 780:, in which convergence is defined 695: 663: 657: 468: 405: 364: 320: 14: 1867: 1674: 1520: 1331:{\displaystyle {\mathcal {T}}(G)} 1111:(taking a natural transformation 307:tensor product of representations 235:In Pontryagin duality theory for 980:{\displaystyle \Gamma (\Pi (G))} 810:{\displaystyle \{\varphi _{a}\}} 681:{\displaystyle \Gamma (\Pi (G))} 490:an endomorphism of the space of 23: 1684:Reports on Mathematical Physics 1551:rational conformal field theory 949:. It can be shown that the set 148:, between compact and discrete 144:. It is a natural extension of 34:needs additional citations for 1792:Joyal, A.; Street, R. (1991), 1634: 1388: 1382: 1372: 1325: 1319: 1180: 1174: 1088: 974: 971: 965: 959: 936: 930: 895: 889: 863: 857: 763: 757: 751: 745: 736: 730: 704: 698: 675: 672: 666: 660: 631: 625: 616: 610: 587:{\displaystyle f\colon T\to U} 578: 546: 540: 531: 525: 516: 504: 477: 471: 414: 408: 373: 367: 329: 323: 259: 1: 1841:Unitary representation theory 1724:10.1016/S0034-4877(97)84884-7 1545:), but of more general type, 1539:symmetric monoidal categories 1052:. One puts a topology on the 991:Theorems of Tannaka and Krein 348:contragredient representation 1593:a strict symmetric monoidal 1284: 1186:{\displaystyle V\in \Pi (G)} 156:. The theory is named after 7: 1616: 1016:be a compact group and let 901:{\displaystyle \varphi (T)} 271:{\displaystyle {\hat {G}},} 174:category of representations 10: 1872: 1731:Van Daele, Alfons (2000). 1419:1. There exists an object 1342:is a closed subset of End( 1563:Doplicher–Roberts theorem 1557:Doplicher–Roberts theorem 1547:braided monoidal category 1151:{\displaystyle \tau _{V}} 449:that associates with any 1644:Inventiones Mathematicae 1628: 1066:by setting it to be the 1037:from finite-dimensional 830:{\displaystyle \varphi } 442:{\displaystyle \varphi } 282:. If we allow the group 1623:Gelfand–Naimark theorem 1439:with the property that 1054:natural transformations 710:{\displaystyle \Pi (G)} 379:{\displaystyle \Pi (G)} 335:{\displaystyle \Pi (G)} 299:unitary representations 280:unitary representations 209:mathematical physicists 162:Mark Grigorievich Krein 58:"Tannaka–Krein duality" 1612:contains only scalars. 1465: 1433: 1395: 1332: 1299: 1258: 1187: 1152: 1125: 1105: 981: 943: 902: 873: 831: 811: 770: 711: 682: 644: 588: 561:intertwining operators 553: 484: 443: 423: 388:natural transformation 380: 336: 272: 197:Alexander Grothendieck 172:is not a group, but a 142:linear representations 1758:10.1073/pnas.97.2.541 1600:a subcategory having 1466: 1434: 1396: 1333: 1300: 1259: 1188: 1153: 1126: 1124:{\displaystyle \tau } 1106: 982: 944: 903: 874: 832: 812: 771: 712: 683: 645: 589: 559:, and with arbitrary 554: 485: 444: 424: 381: 337: 273: 127:Tannaka–Krein duality 1573:) characterises Rep( 1443: 1423: 1366: 1309: 1276: 1209: 1162: 1135: 1115: 1082: 953: 912: 883: 841: 821: 788: 721: 692: 654: 598: 566: 498: 453: 433: 397: 361: 317: 250: 191:) back to the group 43:improve this article 1836:Monoidal categories 1749:2000PNAS...97..541V 1706:1996RpMP...38..313K 1657:1989InMat..98..157D 1585:of the category of 1264:. We also say that 1195:continuous function 1041:representations of 784:, i.e., a sequence 292:equivalence classes 205:Tannakian formalism 1851:Topological groups 1809:10.1007/BFb0084235 1665:10.1007/BF01388849 1461: 1429: 1391: 1328: 1295: 1254: 1183: 1148: 1121: 1101: 1047:finite-dimensional 977: 939: 898: 869: 827: 817:converges to some 807: 766: 707: 678: 640: 584: 549: 480: 439: 419: 390:from the identity 376: 332: 268: 146:Pontryagin duality 1846:Harmonic analysis 1818:978-3-540-46435-8 1432:{\displaystyle I} 1287: 1199:tensor-preserving 1131:to its component 1035:forgetful functor 996:Tannaka's theorem 650:. The collection 344:monoidal category 262: 221:quantum groupoids 134:topological group 119: 118: 111: 93: 1863: 1856:Duality theories 1821: 1798: 1788: 1778: 1760: 1727: 1717: 1699: 1669: 1668: 1638: 1567:Sergio Doplicher 1478:2. Every object 1471:for all objects 1470: 1468: 1467: 1462: 1438: 1436: 1435: 1430: 1400: 1398: 1397: 1392: 1381: 1380: 1337: 1335: 1334: 1329: 1318: 1317: 1304: 1302: 1301: 1296: 1288: 1280: 1263: 1261: 1260: 1255: 1253: 1252: 1240: 1239: 1227: 1226: 1192: 1190: 1189: 1184: 1157: 1155: 1154: 1149: 1147: 1146: 1130: 1128: 1127: 1122: 1110: 1108: 1107: 1102: 1100: 1099: 986: 984: 983: 978: 948: 946: 945: 940: 907: 905: 904: 899: 878: 876: 875: 870: 856: 855: 836: 834: 833: 828: 816: 814: 813: 808: 803: 802: 775: 773: 772: 767: 716: 714: 713: 708: 687: 685: 684: 679: 649: 647: 646: 641: 593: 591: 590: 585: 558: 556: 555: 550: 489: 487: 486: 481: 448: 446: 445: 440: 428: 426: 425: 420: 418: 417: 385: 383: 382: 377: 357:of the category 341: 339: 338: 333: 277: 275: 274: 269: 264: 263: 255: 201:algebraic groups 114: 107: 103: 100: 94: 92: 51: 27: 19: 1871: 1870: 1866: 1865: 1864: 1862: 1861: 1860: 1826: 1825: 1824: 1819: 1801:Category Theory 1796: 1715:10.1.1.269.3027 1677: 1672: 1639: 1635: 1631: 1619: 1597:with conjugates 1581:, as a type of 1579:category theory 1571:John E. Roberts 1559: 1529:in the work of 1523: 1496: 1444: 1441: 1440: 1424: 1421: 1420: 1405:Krein's theorem 1376: 1375: 1367: 1364: 1363: 1313: 1312: 1310: 1307: 1306: 1279: 1277: 1274: 1273: 1248: 1244: 1235: 1231: 1216: 1212: 1210: 1207: 1206: 1163: 1160: 1159: 1142: 1138: 1136: 1133: 1132: 1116: 1113: 1112: 1095: 1091: 1083: 1080: 1079: 1032: 993: 954: 951: 950: 913: 910: 909: 884: 881: 880: 851: 847: 842: 839: 838: 837:if and only if 822: 819: 818: 798: 794: 789: 786: 785: 722: 719: 718: 693: 690: 689: 655: 652: 651: 599: 596: 595: 567: 564: 563: 499: 496: 495: 454: 451: 450: 434: 431: 430: 404: 400: 398: 395: 394: 362: 359: 358: 318: 315: 314: 254: 253: 251: 248: 247: 245:character group 237:locally compact 233: 225:Hopf algebroids 223:and their dual 115: 104: 98: 95: 52: 50: 40: 28: 17: 12: 11: 5: 1869: 1859: 1858: 1853: 1848: 1843: 1838: 1823: 1822: 1817: 1789: 1728: 1690:(3): 313–324. 1678: 1676: 1675:External links 1673: 1671: 1670: 1651:(1): 157–218. 1632: 1630: 1627: 1626: 1625: 1618: 1615: 1614: 1613: 1598: 1587:Hilbert spaces 1577:) in terms of 1558: 1555: 1527:quantum groups 1522: 1521:Generalization 1519: 1507: 1506: 1494: 1483: 1476: 1460: 1457: 1454: 1451: 1448: 1428: 1390: 1387: 1384: 1379: 1374: 1371: 1327: 1324: 1321: 1316: 1294: 1291: 1286: 1283: 1270:self-conjugate 1251: 1247: 1243: 1238: 1234: 1230: 1225: 1222: 1219: 1215: 1182: 1179: 1176: 1173: 1170: 1167: 1145: 1141: 1120: 1098: 1094: 1090: 1087: 1028: 992: 989: 976: 973: 970: 967: 964: 961: 958: 938: 935: 932: 929: 926: 923: 920: 917: 897: 894: 891: 888: 868: 865: 862: 859: 854: 850: 846: 826: 806: 801: 797: 793: 765: 762: 759: 756: 753: 750: 747: 744: 741: 738: 735: 732: 729: 726: 706: 703: 700: 697: 677: 674: 671: 668: 665: 662: 659: 639: 636: 633: 630: 627: 624: 621: 618: 615: 612: 609: 606: 603: 583: 580: 577: 574: 571: 548: 545: 542: 539: 536: 533: 530: 527: 524: 521: 518: 515: 512: 509: 506: 503: 479: 476: 473: 470: 467: 464: 461: 458: 438: 416: 413: 410: 407: 403: 386:is a monoidal 375: 372: 369: 366: 355:representation 331: 328: 325: 322: 267: 261: 258: 232: 229: 213:quantum groups 166:Lev Pontryagin 154:noncommutative 117: 116: 31: 29: 22: 15: 9: 6: 4: 3: 2: 1868: 1857: 1854: 1852: 1849: 1847: 1844: 1842: 1839: 1837: 1834: 1833: 1831: 1820: 1814: 1810: 1806: 1802: 1795: 1790: 1786: 1782: 1777: 1772: 1768: 1764: 1759: 1754: 1750: 1746: 1742: 1738: 1734: 1729: 1725: 1721: 1716: 1711: 1707: 1703: 1698: 1697:q-alg/9507018 1693: 1689: 1685: 1680: 1679: 1666: 1662: 1658: 1654: 1650: 1646: 1645: 1637: 1633: 1624: 1621: 1620: 1611: 1610:monoidal unit 1607: 1603: 1599: 1596: 1592: 1591: 1590: 1588: 1584: 1580: 1576: 1572: 1568: 1564: 1554: 1552: 1548: 1544: 1540: 1536: 1532: 1528: 1518: 1516: 1512: 1504: 1500: 1492: 1488: 1484: 1481: 1477: 1474: 1458: 1455: 1452: 1449: 1446: 1426: 1418: 1417: 1416: 1414: 1408: 1406: 1402: 1385: 1369: 1361: 1357: 1353: 1349: 1345: 1341: 1322: 1292: 1289: 1281: 1271: 1267: 1249: 1245: 1241: 1236: 1232: 1228: 1223: 1220: 1217: 1213: 1204: 1200: 1196: 1177: 1168: 1165: 1143: 1139: 1118: 1096: 1092: 1085: 1077: 1073: 1069: 1065: 1061: 1058: 1055: 1051: 1050:vector spaces 1048: 1044: 1040: 1036: 1031: 1027: 1023: 1019: 1015: 1010: 1008: 1004: 1001: 1000:compact group 997: 988: 968: 933: 924: 921: 918: 915: 892: 886: 879:converges to 860: 852: 848: 824: 799: 795: 783: 779: 760: 754: 748: 742: 739: 733: 727: 724: 701: 669: 637: 634: 628: 622: 619: 613: 607: 604: 601: 581: 575: 572: 569: 562: 543: 537: 534: 528: 522: 519: 513: 510: 507: 501: 493: 474: 465: 462: 459: 456: 436: 411: 401: 393: 389: 370: 356: 351: 349: 345: 326: 312: 308: 304: 300: 297: 293: 289: 285: 281: 265: 256: 246: 242: 238: 228: 226: 222: 218: 214: 210: 206: 202: 198: 194: 190: 185: 183: 179: 175: 171: 170:compact group 167: 163: 159: 158:Tadao Tannaka 155: 151: 147: 143: 139: 135: 132: 128: 124: 113: 110: 102: 91: 88: 84: 81: 77: 74: 70: 67: 63: 60: –  59: 55: 54:Find sources: 48: 44: 38: 37: 32:This article 30: 26: 21: 20: 1800: 1743:(2): 541–6. 1740: 1736: 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460:∈ 437:φ 406:Π 365:Π 321:Π 260:^ 1785:10639115 1617:See also 1565:(due to 1531:Drinfeld 1074:) → End( 1068:coarsest 908:for all 778:topology 138:category 136:and its 1745:Bibcode 1702:Bibcode 1653:Bibcode 1193:) is a 1039:complex 1033:be the 392:functor 243:is its 131:compact 83:scholar 1815:  1783:  1773:  1767:121658 1765:  1712:  1485:3. If 85:  78:  71:  64:  56:  1797:(PDF) 1776:33963 1763:JSTOR 1692:arXiv 1629:Notes 1535:Jimbo 90:JSTOR 76:books 1813:ISBN 1781:PMID 1604:and 1569:and 1561:The 1533:and 1489:and 1026:Vect 1024:) → 1012:Let 1009:). 776:and 203:via 160:and 62:news 1805:doi 1771:PMC 1753:doi 1720:doi 1661:doi 1354:of 1272:if 1268:is 1158:at 301:of 294:of 290:of 288:set 140:of 121:In 45:by 1832:: 1811:, 1799:, 1779:. 1769:. 1761:. 1751:. 1741:97 1739:. 1735:. 1718:. 1708:. 1700:. 1688:38 1686:. 1659:. 1649:98 1647:. 1541:Π( 1501:, 1415:. 1062:→ 1057:τ: 1020:Π( 1018:F: 922:Ob 463:Ob 402:id 353:A 350:. 227:. 219:, 184:. 176:Π( 125:, 1807:: 1787:. 1755:: 1747:: 1726:. 1722:: 1704:: 1694:: 1667:. 1663:: 1655:: 1575:G 1543:G 1515:G 1511:G 1503:B 1499:A 1497:( 1495:Π 1491:B 1487:A 1480:A 1473:A 1459:A 1453:A 1447:I 1427:I 1413:G 1389:) 1386:G 1383:( 1378:T 1370:G 1360:x 1356:G 1352:x 1348:G 1344:F 1340:F 1326:) 1323:G 1320:( 1315:T 1290:= 1266:τ 1250:W 1237:V 1229:= 1224:W 1218:V 1203:G 1181:) 1178:G 1175:( 1166:V 1144:V 1097:V 1076:V 1072:F 1064:F 1060:F 1043:G 1030:C 1022:G 1014:G 1007:G 1003:G 975:) 972:) 969:G 966:( 960:( 937:) 934:G 931:( 916:T 896:) 893:T 890:( 867:} 864:) 861:T 858:( 853:a 845:{ 805:} 800:a 792:{ 764:) 761:T 758:( 752:) 749:T 746:( 740:= 737:) 734:T 731:( 705:) 702:G 699:( 676:) 673:) 670:G 667:( 661:( 638:f 632:) 629:U 626:( 620:= 617:) 614:T 611:( 602:f 582:U 576:T 570:f 547:) 544:U 541:( 532:) 529:T 526:( 520:= 517:) 514:U 508:T 505:( 492:T 478:) 475:G 472:( 457:T 415:) 412:G 409:( 374:) 371:G 368:( 330:) 327:G 324:( 311:G 303:G 284:G 266:, 257:G 241:G 193:G 189:G 182:G 178:G 112:) 106:( 101:) 97:( 87:· 80:· 73:· 66:· 39:.

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"Tannaka–Krein duality"
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mathematics
compact
topological group
category
linear representations
Pontryagin duality
commutative
noncommutative
Tadao Tannaka
Mark Grigorievich Krein
Lev Pontryagin
compact group
category of representations
Alexander Grothendieck
algebraic groups
Tannakian formalism
mathematical physicists
quantum groups
supergroups

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