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Group representation

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1544: 1300: 1777: 217:— Many important Lie groups are compact, so the results of compact representation theory apply to them. Other techniques specific to Lie groups are used as well. Most of the groups important in physics and chemistry are Lie groups, and their representation theory is crucial to the application of group theory in those fields. See 189:— Many of the results of finite group representation theory are proved by averaging over the group. These proofs can be carried over to infinite groups by replacement of the average with an integral, provided that an acceptable notion of integral can be defined. This can be done for locally compact groups, using the 1354: 248:. Although linear algebraic groups have a classification that is very similar to that of Lie groups, and give rise to the same families of Lie algebras, their representations are rather different (and much less well understood). The analytic techniques used for studying Lie groups must be replaced by techniques from 1110: 1591: 27: 138:
The representation theory of groups divides into subtheories depending on the kind of group being represented. The various theories are quite different in detail, though some basic definitions and concepts are similar. The most important divisions are:
1539:{\displaystyle \sigma \left(1\right)={\begin{bmatrix}1&0\\0&1\\\end{bmatrix}}\qquad \sigma \left(u\right)={\begin{bmatrix}u&0\\0&1\\\end{bmatrix}}\qquad \sigma \left(u^{2}\right)={\begin{bmatrix}u^{2}&0\\0&1\\\end{bmatrix}}.} 1295:{\displaystyle \rho \left(1\right)={\begin{bmatrix}1&0\\0&1\\\end{bmatrix}}\qquad \rho \left(u\right)={\begin{bmatrix}1&0\\0&u\\\end{bmatrix}}\qquad \rho \left(u^{2}\right)={\begin{bmatrix}1&0\\0&u^{2}\\\end{bmatrix}}.} 572: 1882: 1772:{\displaystyle \tau \left(1\right)={\begin{bmatrix}1&0\\0&1\\\end{bmatrix}}\qquad \tau \left(u\right)={\begin{bmatrix}a&-b\\b&a\\\end{bmatrix}}\qquad \tau \left(u^{2}\right)={\begin{bmatrix}a&b\\-b&a\\\end{bmatrix}}} 2768: 2194:
In the example above, the first two representations given (ρ and σ) are both decomposable into two 1-dimensional subrepresentations (given by span{(1,0)} and span{(0,1)}), while the third representation (τ) is irreducible.
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on which the group acts. One distinguishes between finite-dimensional representations and infinite-dimensional ones. In the infinite-dimensional case, additional structures are important (e.g. whether or not the space is a
852: 1036: 438: 2436: 262:— The class of non-compact groups is too broad to construct any general representation theory, but specific special cases have been studied, sometimes using ad hoc techniques. The 1964: 1583: 1346: 1102: 110:
is also used in a more general sense to mean any "description" of a group as a group of transformations of some mathematical object. More formally, a "representation" means a
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for the special case of linear representations. The bulk of this article describes linear representation theory; see the last section for generalizations.
148:— Group representations are a very important tool in the study of finite groups. They also arise in the applications of finite group theory to 780: 2156:. The representation of dimension zero is considered to be neither reducible nor irreducible, just as the number 1 is considered to be neither 972: 2884: 395: 382: 2610:, this definition is equivalent to a linear representation. Likewise, a set-theoretic representation is just a representation of 84:
In chemistry, a group representation can relate mathematical group elements to symmetric rotations and reflections of molecules.
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of the field is also significant; many theorems for finite groups depend on the characteristic of the field not dividing the
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Lie groups cannot be classified in the same way. The general theory for Lie groups deals with
2874: 2688: 185: 78: 62: 47: 2835: 2184: 2180: 1971: 333: 325: 2021: 8: 2217: 363: 349: 305: 153: 55: 31: 240:) — These are the analogues of Lie groups, but over more general fields than just 2728: 2579: 2486: 2444: 1998: 1910:
be the space of homogeneous degree-3 polynomials over the complex numbers in variables
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over which the vector space is defined. The most important case is the field of
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of a physical system affects the solutions of equations describing that system.
309: 100: 92: 35: 2817: 2187:). This holds in particular for any representation of a finite group over the 601:
itself as the representation when the homomorphism is clear from the context.
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has exactly two subrepresentations, namely the zero-dimensional subspace and
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Two types of representations closely related to linear representations are:
847:{\displaystyle \ker \rho =\left\{g\in G\mid \rho (g)=\mathrm {id} \right\}.} 2692: 2176: 2161: 1072: 356: 317: 313: 298: 289: 236: 190: 144: 111: 88: 70: 66: 2474: 939: 43: 2849: 2485:. Thus we may equivalently define a permutation representation to be a 213: 26: 2812:, Readings in Mathematics. Vol. 129. New York: Springer-Verlag. 2470: 1306: 876: 59: 328:
fields are easier to handle than non-algebraically closed ones. The
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have a deep theory, building on the compact case. The complementary
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Group homomorphism into the general linear group over a vector space
2634: 2527: 73:); in particular, they can be used to represent group elements as 2551: 96: 38:, consisting of reflections and rotations, transform the polygon. 1031:{\displaystyle \alpha \circ \rho (g)\circ \alpha ^{-1}=\pi (g).} 2858:
Introduction to the Theory of Banach Representations of Groups
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describes the theory for commutative groups, as a generalised
2682: 879:; in other words, one whose kernel is the trivial subgroup { 433:{\displaystyle \rho \colon G\to \mathrm {GL} \left(V\right)} 1075:
under multiplication. This group has a representation ρ on
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does not divide the size of the group, representations of
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Representation theory also depends heavily on the type of
133: 2848:. Introduction to representation theory with emphasis on 2465:. This condition and the axioms for a group imply that ρ( 597:
of the representation. It is common practice to refer to
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of an object. If the object is a vector space we have a
173:; this special case has very different properties. See 2513: 2506:
For more information on this topic see the article on
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of the two types, by means of general results called
2681:. These can be described as "linear representations 167:
divides the order of the group, then this is called
2453: 2430: 2315: 2203: 2100: 2068: 2036: 2007: 1987: 1958: 1902: 1876: 1771: 1577: 1538: 1340: 1294: 1096: 1030: 883:} consisting only of the group's identity element. 846: 654: 566: 432: 77:so that the group operation can be represented by 1348:, isomorphic to the previous one, is σ given by: 34:"acts" on an object. A simple example is how the 2866: 2431:{\displaystyle \rho (g_{1}g_{2})=\rho (g_{1})],} 1305:This representation is faithful because ρ is a 2148:itself, then the representation is said to be 312:. The other important cases are the field of 2796: 193:. The resulting theory is a central part of 126:for the general notion and reserve the term 2530:in this category are just the elements of 1565: 1328: 1084: 25: 2183:of irreducible subrepresentations (see 2015:by permutation of the three variables. 389:. That is, a representation is a map 134:Branches of group representation theory 2867: 2744:Representation theory of finite groups 1556:may also be faithfully represented on 175:Representation theory of finite groups 91:problems to be reduced to problems in 2806:Representation theory. A first course 763:is defined as the normal subgroup of 87:Representations of groups allow many 2739:List of representation theory topics 256:causes many technical complications. 2562:. Such a functor selects an object 2514:Representations in other categories 304:One must also consider the type of 156:of scalars of the vector space has 13: 2633:, the objects obtained are called 2198: 1959:{\displaystyle x_{1},x_{2},x_{3}.} 832: 829: 415: 412: 14: 2896: 2643:For another example consider the 2212:(also known as a group action or 864:is one in which the homomorphism 2734:List of harmonic analysis topics 1578:{\displaystyle \mathbb {R} ^{2}} 1341:{\displaystyle \mathbb {C} ^{2}} 1097:{\displaystyle \mathbb {C} ^{2}} 2885:Representation theory of groups 2204:Set-theoretical representations 2111: 1833: 1705: 1648: 1465: 1411: 1221: 1167: 938:if there exists a vector space 771:is the identity transformation: 526: 280:, which is a generalization of 223:Representations of Lie algebras 36:symmetries of a regular polygon 2761: 2645:category of topological spaces 2570:and a group homomorphism from 2534:. Given an arbitrary category 2422: 2419: 2413: 2410: 2397: 2391: 2388: 2375: 2366: 2360: 2357: 2334: 2304: 2298: 2295: 2289: 2167:Under the assumption that the 2031: 2025: 1851: 1845: 1809: 1803: 1022: 1016: 991: 985: 822: 816: 520: 507: 501: 488: 479: 456: 408: 339: 260:Non-compact topological groups 1: 2810:Graduate Texts in Mathematics 2790: 2663:group of a topological space 219:Representations of Lie groups 170:modular representation theory 69:to itself (i.e. vector space 2242:, the set of functions from 2210:set-theoretic representation 2130:that is invariant under the 1048:Consider the complex number 252:, where the relatively weak 7: 2714:Irreducible representations 2707: 2461:is the identity element of 1312:Another representation for 1052:= e which has the property 1043: 10: 2901: 2675:projective representations 2631:category of abelian groups 2316:{\displaystyle \rho (1)=x} 2214:permutation representation 2118:Irreducible representation 2115: 705:such that the application 18: 2818:10.1007/978-1-4612-0979-9 2749:Semisimple representation 2604:category of vector spaces 2179:can be decomposed into a 2101:{\displaystyle x_{2}^{3}} 2069:{\displaystyle x_{1}^{3}} 691:continuous representation 655:{\displaystyle n\times n} 612:it is common to choose a 108:representation of a group 2754: 2685:scalar transformations". 687:topological vector space 152:and to geometry. If the 99:, they describe how the 19:Not to be confused with 2655:are homomorphisms from 862:faithful representation 608:is of finite dimension 282:Wigner's classification 230:Linear algebraic groups 21:Presentation of a group 2769:"1.4: Representations" 2689:affine representations 2526:with a single object; 2455: 2432: 2317: 2102: 2070: 2038: 2009: 1989: 1960: 1904: 1878: 1773: 1579: 1540: 1342: 1296: 1098: 1032: 900:, two representations 848: 656: 568: 434: 186:locally compact groups 114:from the group to the 63:linear transformations 39: 30:A representation of a 2880:Representation theory 2691:: in the category of 2677:: in the category of 2651:. Representations in 2456: 2433: 2318: 2103: 2071: 2039: 2010: 1990: 1988:{\displaystyle S_{3}} 1961: 1905: 1879: 1774: 1580: 1541: 1343: 1297: 1099: 1033: 849: 657: 585:and the dimension of 569: 435: 264:semisimple Lie groups 120:linear representation 79:matrix multiplication 52:group representations 48:representation theory 29: 2773:Chemistry LibreTexts 2445: 2328: 2283: 2250:, such that for all 2080: 2048: 2037:{\displaystyle (12)} 2022: 1999: 1972: 1914: 1894: 1789: 1592: 1560: 1355: 1323: 1111: 1079: 973: 781: 755:of a representation 701:is a representation 640: 583:representation space 450: 396: 383:general linear group 326:algebraically closed 233:(or more generally 2699:acts affinely upon 2695:. For example, the 2522:can be viewed as a 2097: 2065: 663:invertible matrices 272:semidirect products 75:invertible matrices 2855:Yurii I. Lyubich. 2729:Molecular symmetry 2589:In the case where 2580:automorphism group 2487:group homomorphism 2451: 2428: 2313: 2098: 2083: 2066: 2051: 2034: 2005: 1985: 1956: 1900: 1874: 1869: 1828: 1769: 1763: 1699: 1642: 1575: 1536: 1527: 1459: 1405: 1338: 1292: 1283: 1215: 1161: 1094: 1028: 844: 767:whose image under 652: 604:In the case where 564: 430: 371:group homomorphism 334:order of the group 250:algebraic geometry 207:Peter–Weyl theorem 199:Pontryagin duality 122:. Some people use 116:automorphism group 54:describe abstract 40: 2827:978-0-387-97495-8 2679:projective spaces 2454:{\displaystyle 1} 2185:Maschke's theorem 2137:subrepresentation 2008:{\displaystyle V} 1903:{\displaystyle V} 1887:Another example: 1868: 1864: 1843: 1827: 1801: 679:topological group 530: 203:Fourier transform 195:harmonic analysis 2892: 2847: 2784: 2783: 2781: 2780: 2765: 2724:Character theory 2616:category of sets 2460: 2458: 2457: 2452: 2437: 2435: 2434: 2429: 2409: 2408: 2387: 2386: 2356: 2355: 2346: 2345: 2322: 2320: 2319: 2314: 2107: 2105: 2104: 2099: 2096: 2091: 2075: 2073: 2072: 2067: 2064: 2059: 2043: 2041: 2040: 2035: 2014: 2012: 2011: 2006: 1994: 1992: 1991: 1986: 1984: 1983: 1965: 1963: 1962: 1957: 1952: 1951: 1939: 1938: 1926: 1925: 1909: 1907: 1906: 1901: 1883: 1881: 1880: 1875: 1870: 1860: 1859: 1844: 1841: 1829: 1820: 1802: 1799: 1778: 1776: 1775: 1770: 1768: 1767: 1726: 1722: 1721: 1704: 1703: 1662: 1647: 1646: 1608: 1584: 1582: 1581: 1576: 1574: 1573: 1568: 1545: 1543: 1542: 1537: 1532: 1531: 1507: 1506: 1486: 1482: 1481: 1464: 1463: 1425: 1410: 1409: 1371: 1347: 1345: 1344: 1339: 1337: 1336: 1331: 1301: 1299: 1298: 1293: 1288: 1287: 1280: 1279: 1242: 1238: 1237: 1220: 1219: 1181: 1166: 1165: 1127: 1103: 1101: 1100: 1095: 1093: 1092: 1087: 1037: 1035: 1034: 1029: 1009: 1008: 955:so that for all 954: 929: 914: 874: 853: 851: 850: 845: 840: 836: 835: 743: 719: 661: 659: 658: 653: 635: 620:and identify GL( 573: 571: 570: 565: 554: 553: 541: 540: 531: 528: 519: 518: 500: 499: 478: 477: 468: 467: 439: 437: 436: 431: 429: 418: 320:, and fields of 254:Zariski topology 2900: 2899: 2895: 2894: 2893: 2891: 2890: 2889: 2865: 2864: 2828: 2798:Fulton, William 2793: 2788: 2787: 2778: 2776: 2767: 2766: 2762: 2757: 2719:Character table 2710: 2701:Euclidean space 2697:Euclidean group 2601: 2516: 2498: 2491:symmetric group 2446: 2443: 2442: 2404: 2400: 2382: 2378: 2351: 2347: 2341: 2337: 2329: 2326: 2325: 2284: 2281: 2280: 2263: 2256: 2206: 2201: 2199:Generalizations 2189:complex numbers 2120: 2114: 2092: 2087: 2081: 2078: 2077: 2060: 2055: 2049: 2046: 2045: 2023: 2020: 2019: 2000: 1997: 1996: 1979: 1975: 1973: 1970: 1969: 1947: 1943: 1934: 1930: 1921: 1917: 1915: 1912: 1911: 1895: 1892: 1891: 1857: 1840: 1818: 1798: 1790: 1787: 1786: 1762: 1761: 1756: 1747: 1746: 1741: 1731: 1730: 1717: 1713: 1709: 1698: 1697: 1692: 1686: 1685: 1677: 1667: 1666: 1652: 1641: 1640: 1635: 1629: 1628: 1623: 1613: 1612: 1598: 1593: 1590: 1589: 1585:by τ given by: 1569: 1564: 1563: 1561: 1558: 1557: 1555: 1526: 1525: 1520: 1514: 1513: 1508: 1502: 1498: 1491: 1490: 1477: 1473: 1469: 1458: 1457: 1452: 1446: 1445: 1440: 1430: 1429: 1415: 1404: 1403: 1398: 1392: 1391: 1386: 1376: 1375: 1361: 1356: 1353: 1352: 1332: 1327: 1326: 1324: 1321: 1320: 1318: 1282: 1281: 1275: 1271: 1269: 1263: 1262: 1257: 1247: 1246: 1233: 1229: 1225: 1214: 1213: 1208: 1202: 1201: 1196: 1186: 1185: 1171: 1160: 1159: 1154: 1148: 1147: 1142: 1132: 1131: 1117: 1112: 1109: 1108: 1088: 1083: 1082: 1080: 1077: 1076: 1062: 1046: 1001: 997: 974: 971: 970: 942: 930:are said to be 916: 901: 865: 828: 800: 796: 782: 779: 778: 721: 706: 641: 638: 637: 636:, the group of 625: 549: 545: 536: 532: 527: 514: 510: 495: 491: 473: 469: 463: 459: 451: 448: 447: 419: 411: 397: 394: 393: 342: 310:complex numbers 150:crystallography 136: 89:group-theoretic 24: 17: 12: 11: 5: 2898: 2888: 2887: 2882: 2877: 2863: 2862: 2853: 2826: 2792: 2789: 2786: 2785: 2759: 2758: 2756: 2753: 2752: 2751: 2746: 2741: 2736: 2731: 2726: 2721: 2716: 2709: 2706: 2705: 2704: 2686: 2597: 2540:representation 2515: 2512: 2494: 2489:from G to the 2450: 2439: 2438: 2427: 2424: 2421: 2418: 2415: 2412: 2407: 2403: 2399: 2396: 2393: 2390: 2385: 2381: 2377: 2374: 2371: 2368: 2365: 2362: 2359: 2354: 2350: 2344: 2340: 2336: 2333: 2323: 2312: 2309: 2306: 2303: 2300: 2297: 2294: 2291: 2288: 2261: 2254: 2230:is given by a 2205: 2202: 2200: 2197: 2169:characteristic 2116:Main article: 2113: 2110: 2095: 2090: 2086: 2063: 2058: 2054: 2033: 2030: 2027: 2018:For instance, 2004: 1982: 1978: 1955: 1950: 1946: 1942: 1937: 1933: 1929: 1924: 1920: 1899: 1885: 1884: 1873: 1867: 1863: 1856: 1853: 1850: 1847: 1839: 1836: 1832: 1826: 1823: 1817: 1814: 1811: 1808: 1805: 1797: 1794: 1780: 1779: 1766: 1760: 1757: 1755: 1752: 1749: 1748: 1745: 1742: 1740: 1737: 1736: 1734: 1729: 1725: 1720: 1716: 1712: 1708: 1702: 1696: 1693: 1691: 1688: 1687: 1684: 1681: 1678: 1676: 1673: 1672: 1670: 1665: 1661: 1658: 1655: 1651: 1645: 1639: 1636: 1634: 1631: 1630: 1627: 1624: 1622: 1619: 1618: 1616: 1611: 1607: 1604: 1601: 1597: 1572: 1567: 1553: 1547: 1546: 1535: 1530: 1524: 1521: 1519: 1516: 1515: 1512: 1509: 1505: 1501: 1497: 1496: 1494: 1489: 1485: 1480: 1476: 1472: 1468: 1462: 1456: 1453: 1451: 1448: 1447: 1444: 1441: 1439: 1436: 1435: 1433: 1428: 1424: 1421: 1418: 1414: 1408: 1402: 1399: 1397: 1394: 1393: 1390: 1387: 1385: 1382: 1381: 1379: 1374: 1370: 1367: 1364: 1360: 1335: 1330: 1316: 1307:one-to-one map 1303: 1302: 1291: 1286: 1278: 1274: 1270: 1268: 1265: 1264: 1261: 1258: 1256: 1253: 1252: 1250: 1245: 1241: 1236: 1232: 1228: 1224: 1218: 1212: 1209: 1207: 1204: 1203: 1200: 1197: 1195: 1192: 1191: 1189: 1184: 1180: 1177: 1174: 1170: 1164: 1158: 1155: 1153: 1150: 1149: 1146: 1143: 1141: 1138: 1137: 1135: 1130: 1126: 1123: 1120: 1116: 1091: 1086: 1060: 1045: 1042: 1041: 1040: 1039: 1038: 1027: 1024: 1021: 1018: 1015: 1012: 1007: 1004: 1000: 996: 993: 990: 987: 984: 981: 978: 965: 964: 892:vector spaces 885: 884: 857: 856: 855: 854: 843: 839: 834: 831: 827: 824: 821: 818: 815: 812: 809: 806: 803: 799: 795: 792: 789: 786: 773: 772: 749: 651: 648: 645: 589:is called the 581:is called the 575: 574: 563: 560: 557: 552: 548: 544: 539: 535: 525: 522: 517: 513: 509: 506: 503: 498: 494: 490: 487: 484: 481: 476: 472: 466: 462: 458: 455: 441: 440: 428: 425: 422: 417: 414: 410: 407: 404: 401: 346:representation 341: 338: 330:characteristic 324:. In general, 322:p-adic numbers 286: 285: 257: 226: 210: 182:Compact groups 178: 158:characteristic 135: 132: 128:representation 101:symmetry group 93:linear algebra 15: 9: 6: 4: 3: 2: 2897: 2886: 2883: 2881: 2878: 2876: 2873: 2872: 2870: 2860: 2859: 2854: 2851: 2845: 2841: 2837: 2833: 2829: 2823: 2819: 2815: 2811: 2807: 2803: 2799: 2795: 2794: 2774: 2770: 2764: 2760: 2750: 2747: 2745: 2742: 2740: 2737: 2735: 2732: 2730: 2727: 2725: 2722: 2720: 2717: 2715: 2712: 2711: 2702: 2698: 2694: 2693:affine spaces 2690: 2687: 2684: 2680: 2676: 2673: 2672: 2671: 2668: 2666: 2662: 2661:homeomorphism 2658: 2654: 2650: 2646: 2641: 2639: 2637: 2632: 2628: 2624: 2619: 2617: 2613: 2609: 2606:over a field 2605: 2600: 2596: 2592: 2587: 2585: 2581: 2577: 2573: 2569: 2565: 2561: 2557: 2553: 2549: 2545: 2541: 2537: 2533: 2529: 2525: 2521: 2511: 2509: 2504: 2502: 2497: 2492: 2488: 2484: 2480: 2476: 2472: 2468: 2464: 2448: 2425: 2416: 2405: 2401: 2394: 2383: 2379: 2372: 2369: 2363: 2352: 2348: 2342: 2338: 2331: 2324: 2310: 2307: 2301: 2292: 2286: 2279: 2278: 2277: 2275: 2271: 2267: 2260: 2253: 2249: 2245: 2241: 2237: 2233: 2229: 2226: 2222: 2219: 2215: 2211: 2196: 2192: 2190: 2186: 2182: 2178: 2177:finite groups 2174: 2171:of the field 2170: 2165: 2163: 2159: 2155: 2151: 2147: 2143: 2139: 2138: 2133: 2129: 2125: 2119: 2109: 2093: 2088: 2084: 2061: 2056: 2052: 2028: 2016: 2002: 1980: 1976: 1966: 1953: 1948: 1944: 1940: 1935: 1931: 1927: 1922: 1918: 1897: 1888: 1871: 1865: 1861: 1854: 1848: 1837: 1834: 1830: 1824: 1821: 1815: 1812: 1806: 1795: 1792: 1785: 1784: 1783: 1764: 1758: 1753: 1750: 1743: 1738: 1732: 1727: 1723: 1718: 1714: 1710: 1706: 1700: 1694: 1689: 1682: 1679: 1674: 1668: 1663: 1659: 1656: 1653: 1649: 1643: 1637: 1632: 1625: 1620: 1614: 1609: 1605: 1602: 1599: 1595: 1588: 1587: 1586: 1570: 1552: 1533: 1528: 1522: 1517: 1510: 1503: 1499: 1492: 1487: 1483: 1478: 1474: 1470: 1466: 1460: 1454: 1449: 1442: 1437: 1431: 1426: 1422: 1419: 1416: 1412: 1406: 1400: 1395: 1388: 1383: 1377: 1372: 1368: 1365: 1362: 1358: 1351: 1350: 1349: 1333: 1315: 1310: 1308: 1289: 1284: 1276: 1272: 1266: 1259: 1254: 1248: 1243: 1239: 1234: 1230: 1226: 1222: 1216: 1210: 1205: 1198: 1193: 1187: 1182: 1178: 1175: 1172: 1168: 1162: 1156: 1151: 1144: 1139: 1133: 1128: 1124: 1121: 1118: 1114: 1107: 1106: 1105: 1089: 1074: 1070: 1066: 1059: 1056:= 1. The set 1055: 1051: 1025: 1019: 1013: 1010: 1005: 1002: 998: 994: 988: 982: 979: 976: 969: 968: 967: 966: 962: 958: 953: 949: 945: 941: 937: 933: 927: 923: 919: 912: 908: 904: 899: 895: 891: 887: 886: 882: 878: 872: 868: 863: 859: 858: 841: 837: 825: 819: 813: 810: 807: 804: 801: 797: 793: 790: 787: 784: 777: 776: 775: 774: 770: 766: 762: 758: 754: 750: 747: 741: 737: 733: 729: 725: 718: 714: 710: 704: 700: 696: 692: 688: 684: 680: 676: 672: 671: 670: 668: 665:on the field 664: 649: 646: 643: 633: 629: 623: 619: 615: 611: 607: 602: 600: 596: 592: 588: 584: 580: 561: 558: 555: 550: 546: 542: 537: 533: 529:for all  523: 515: 511: 504: 496: 492: 485: 482: 474: 470: 464: 460: 453: 446: 445: 444: 426: 423: 420: 405: 402: 399: 392: 391: 390: 388: 384: 380: 376: 372: 368: 365: 361: 358: 354: 351: 347: 337: 335: 331: 327: 323: 319: 318:finite fields 315: 311: 307: 302: 300: 296: 295:Hilbert space 291: 283: 279: 278: 277:Mackey theory 273: 269: 265: 261: 258: 255: 251: 247: 243: 239: 238: 237:group schemes 232: 231: 227: 224: 220: 216: 215: 211: 208: 204: 200: 196: 192: 188: 187: 183: 179: 176: 172: 171: 166: 162: 159: 155: 151: 147: 146: 145:Finite groups 142: 141: 140: 131: 129: 125: 121: 117: 113: 109: 104: 102: 98: 94: 90: 85: 82: 80: 76: 72: 71:automorphisms 68: 64: 61: 57: 53: 49: 45: 37: 33: 28: 22: 2875:Group theory 2856: 2805: 2777:. Retrieved 2775:. 2019-09-04 2772: 2763: 2669: 2664: 2656: 2652: 2648: 2642: 2635: 2626: 2622: 2620: 2611: 2607: 2598: 2594: 2590: 2588: 2583: 2575: 2571: 2567: 2563: 2559: 2555: 2547: 2543: 2539: 2535: 2531: 2519: 2518:Every group 2517: 2508:group action 2505: 2500: 2495: 2482: 2478: 2466: 2462: 2440: 2273: 2269: 2265: 2258: 2251: 2247: 2243: 2239: 2235: 2227: 2220: 2213: 2209: 2207: 2193: 2172: 2166: 2153: 2149: 2145: 2141: 2135: 2134:is called a 2132:group action 2127: 2123: 2121: 2112:Reducibility 2017: 1967: 1889: 1886: 1781: 1550: 1548: 1313: 1311: 1304: 1073:cyclic group 1068: 1064: 1057: 1053: 1049: 1047: 960: 956: 951: 947: 943: 935: 931: 925: 921: 917: 910: 906: 902: 897: 893: 889: 880: 870: 866: 768: 764: 760: 756: 752: 739: 735: 731: 727: 723: 716: 712: 708: 702: 698: 694: 690: 682: 674: 666: 631: 627: 621: 617: 609: 605: 603: 598: 594: 590: 586: 582: 578: 576: 442: 386: 378: 374: 366: 359: 357:vector space 352: 345: 343: 314:real numbers 303: 299:Banach space 290:vector space 287: 275: 267: 263: 259: 245: 241: 234: 228: 212: 205:. See also: 191:Haar measure 180: 168: 164: 160: 143: 137: 127: 123: 119: 112:homomorphism 107: 105: 86: 83: 67:vector space 58:in terms of 51: 44:mathematical 41: 2802:Harris, Joe 2475:permutation 2150:irreducible 2122:A subspace 940:isomorphism 759:of a group 720:defined by 340:Definitions 124:realization 2869:Categories 2850:Lie groups 2791:References 2779:2021-06-23 2477:) for all 2181:direct sum 1549:The group 1104:given by: 1071:} forms a 936:isomorphic 932:equivalent 888:Given two 746:continuous 443:such that 214:Lie groups 2844:246650103 2528:morphisms 2471:bijection 2395:ρ 2373:ρ 2332:ρ 2287:ρ 2234:ρ : 2158:composite 2154:reducible 1816:− 1751:− 1707:τ 1680:− 1650:τ 1596:τ 1467:σ 1413:σ 1359:σ 1223:ρ 1169:ρ 1115:ρ 1014:π 1003:− 999:α 995:∘ 983:ρ 980:∘ 977:α 877:injective 814:ρ 811:∣ 805:∈ 791:ρ 788:⁡ 707:Φ : 647:× 591:dimension 556:∈ 505:ρ 486:ρ 454:ρ 409:→ 403:: 400:ρ 301:, etc.). 163:, and if 106:The term 60:bijective 46:field of 2804:(1991). 2708:See also 2638:-modules 2524:category 2268:and all 2232:function 1995:acts on 1044:Examples 946: : 920: : 905: : 284:methods. 268:solvable 2836:1153249 2659:to the 2614:in the 2578:), the 2574:to Aut( 2552:functor 2469:) is a 2216:) of a 624:) with 381:), the 362:over a 235:affine 97:physics 42:In the 2842:  2834:  2824:  2629:, the 2602:, the 2441:where 2044:sends 1782:where 1063:= {1, 753:kernel 595:degree 377:to GL( 197:. The 56:groups 2755:Notes 2683:up to 2621:When 2554:from 2550:is a 2223:on a 2218:group 2162:prime 2140:. If 1968:Then 924:→ GL( 909:→ GL( 869:→ GL( 685:is a 677:is a 614:basis 577:Here 373:from 369:is a 364:field 355:on a 350:group 348:of a 306:field 154:field 95:. In 65:of a 32:group 2840:OCLC 2822:ISBN 2595:Vect 2538:, a 2473:(or 2160:nor 1890:Let 915:and 896:and 751:The 730:) = 689:, a 681:and 616:for 221:and 2814:doi 2653:Top 2649:Top 2625:is 2593:is 2582:of 2566:in 2558:to 2546:in 2542:of 2499:of 2481:in 2272:in 2264:in 2246:to 2225:set 2126:of 2076:to 1319:on 959:in 934:or 875:is 785:ker 744:is 697:on 693:of 673:If 626:GL( 593:or 385:on 244:or 184:or 2871:: 2838:. 2832:MR 2830:. 2820:. 2808:. 2800:; 2771:. 2667:. 2647:, 2640:. 2627:Ab 2618:. 2586:. 2510:. 2503:. 2276:: 2257:, 2238:→ 2208:A 2164:. 2108:. 2029:12 1842:Im 1800:Re 1309:. 1067:, 950:→ 860:A 738:)( 726:, 722:Φ( 715:→ 711:× 669:. 630:, 344:A 336:. 316:, 297:, 81:. 50:, 2852:. 2846:. 2816:: 2782:. 2703:. 2665:X 2657:G 2636:G 2623:C 2612:G 2608:K 2599:K 2591:C 2584:X 2576:X 2572:G 2568:C 2564:X 2560:C 2556:G 2548:C 2544:G 2536:C 2532:G 2520:G 2501:X 2496:X 2493:S 2483:G 2479:g 2467:g 2463:G 2449:1 2426:, 2423:] 2420:] 2417:x 2414:[ 2411:) 2406:2 2402:g 2398:( 2392:[ 2389:) 2384:1 2380:g 2376:( 2370:= 2367:] 2364:x 2361:[ 2358:) 2353:2 2349:g 2343:1 2339:g 2335:( 2311:x 2308:= 2305:] 2302:x 2299:[ 2296:) 2293:1 2290:( 2274:X 2270:x 2266:G 2262:2 2259:g 2255:1 2252:g 2248:X 2244:X 2240:X 2236:G 2228:X 2221:G 2173:K 2146:V 2142:V 2128:V 2124:W 2094:3 2089:2 2085:x 2062:3 2057:1 2053:x 2032:) 2026:( 2003:V 1981:3 1977:S 1954:. 1949:3 1945:x 1941:, 1936:2 1932:x 1928:, 1923:1 1919:x 1898:V 1872:. 1866:2 1862:3 1855:= 1852:) 1849:u 1846:( 1838:= 1835:b 1831:, 1825:2 1822:1 1813:= 1810:) 1807:u 1804:( 1796:= 1793:a 1765:] 1759:a 1754:b 1744:b 1739:a 1733:[ 1728:= 1724:) 1719:2 1715:u 1711:( 1701:] 1695:a 1690:b 1683:b 1675:a 1669:[ 1664:= 1660:) 1657:u 1654:( 1644:] 1638:1 1633:0 1626:0 1621:1 1615:[ 1610:= 1606:) 1603:1 1600:( 1571:2 1566:R 1554:3 1551:C 1534:. 1529:] 1523:1 1518:0 1511:0 1504:2 1500:u 1493:[ 1488:= 1484:) 1479:2 1475:u 1471:( 1461:] 1455:1 1450:0 1443:0 1438:u 1432:[ 1427:= 1423:) 1420:u 1417:( 1407:] 1401:1 1396:0 1389:0 1384:1 1378:[ 1373:= 1369:) 1366:1 1363:( 1334:2 1329:C 1317:3 1314:C 1290:. 1285:] 1277:2 1273:u 1267:0 1260:0 1255:1 1249:[ 1244:= 1240:) 1235:2 1231:u 1227:( 1217:] 1211:u 1206:0 1199:0 1194:1 1188:[ 1183:= 1179:) 1176:u 1173:( 1163:] 1157:1 1152:0 1145:0 1140:1 1134:[ 1129:= 1125:) 1122:1 1119:( 1090:2 1085:C 1069:u 1065:u 1061:3 1058:C 1054:u 1050:u 1026:. 1023:) 1020:g 1017:( 1011:= 1006:1 992:) 989:g 986:( 963:, 961:G 957:g 952:W 948:V 944:α 928:) 926:W 922:G 918:π 913:) 911:V 907:G 903:ρ 898:W 894:V 890:K 881:e 873:) 871:V 867:G 842:. 838:} 833:d 830:i 826:= 823:) 820:g 817:( 808:G 802:g 798:{ 794:= 769:ρ 765:G 761:G 757:ρ 748:. 742:) 740:v 736:g 734:( 732:ρ 728:v 724:g 717:V 713:V 709:G 703:ρ 699:V 695:G 683:V 675:G 667:K 650:n 644:n 634:) 632:K 628:n 622:V 618:V 610:n 606:V 599:V 587:V 579:V 562:. 559:G 551:2 547:g 543:, 538:1 534:g 524:, 521:) 516:2 512:g 508:( 502:) 497:1 493:g 489:( 483:= 480:) 475:2 471:g 465:1 461:g 457:( 427:) 424:V 421:( 416:L 413:G 406:G 387:V 379:V 375:G 367:K 360:V 353:G 246:C 242:R 225:. 209:. 177:. 165:p 161:p 23:.

Index

Presentation of a group

group
symmetries of a regular polygon
mathematical
representation theory
groups
bijective
linear transformations
vector space
automorphisms
invertible matrices
matrix multiplication
group-theoretic
linear algebra
physics
symmetry group
homomorphism
automorphism group
Finite groups
crystallography
field
characteristic
modular representation theory
Representation theory of finite groups
Compact groups
locally compact groups
Haar measure
harmonic analysis
Pontryagin duality

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