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Core (group theory)

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36: 1126: 889: 1346: 761: 294: 634: 1533: 539: 475: 576: 578:. This causes only a small amount of confusion, because one can usually distinguish between the core of a group and the core of a subgroup within a group. The 1121:{\displaystyle O_{\pi _{1},\pi _{2},\dots ,\pi _{n+1}}(G)/O_{\pi _{1},\pi _{2},\dots ,\pi _{n}}(G)=O_{\pi _{n+1}}(G/O_{\pi _{1},\pi _{2},\dots ,\pi _{n}}(G))} 542: 209: 57: 1226: 1680: 1650: 1627: 1601: 79: 1672: 1642: 639: 1668: 1435:′-core is the intersection of the kernels of the ordinary (complex) irreducible representations that lie in the principal 1412: 50: 44: 1593: 1400: 169: 61: 173: 358: 332: 1708: 351: 1463:-core is the intersection of the centralizers of the abelian chief factors whose order is divisible by 1660: 393: 328: 1502: 109: 1585: 592: 503: 1676: 1646: 1623: 1597: 444: 324: 320: 1447:-core is the intersection of the kernels of the irreducible representations in the principal 1686: 1544: 478: 347: 336: 1690: 552: 397: 157: 105: 1612: 1496: 1165: 430: 350:. Equivalently, it is a subgroup that occurs as the isotropy subgroup of a transitive, 365:
case generalizes to finding the normal core in case of subgroups of arbitrary groups.
1702: 1424: 1215: 362: 1559:′-core of its solvable radical in order to better mimic properties of the 2′-core. 1416: 482: 409: 389: 316: 93: 299:
Under this more general definition, the normal core is the core with respect to
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A related subgroup in concept and notation is the solvable radical. The
1475:-constrained group, an irreducible module over a field of characteristic 117: 377:"P-core" redirects here. For the computer central processing units, see 423: 1483:′-core of the group is contained in the kernel of the representation. 185: 289:{\displaystyle \mathrm {Core} _{S}(H):=\bigcap _{s\in S}{s^{-1}Hs}.} 1467:(all of which are irreducible representations over a field of size 1423:-core of a finite group is the intersection of the kernels of the 307:. The normal core of any normal subgroup is the subgroup itself. 1341:{\displaystyle C_{G}(O_{p',p}(G)/O_{p'}(G))\subseteq O_{p',p}(G)} 29: 477:, and in particular appears in one of the definitions of the 1535:. There is some variance in the literature in defining the 335:, the normal core of any isotropy subgroup is precisely the 782:-core can also be defined as the unique largest subnormal 541:. In the area of finite insoluble groups, including the 756:{\displaystyle O_{p',p}(G)/O_{p'}(G)=O_{p}(G/O_{p'}(G))} 1547:'s N-group papers, but not his later work) define the 422:
of a finite group is defined to be its largest normal
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if and only if it is equal to some term of its upper
892: 642: 595: 555: 506: 447: 212: 1543:. A few authors in only a few papers (for instance 1611: 1527: 1340: 1120: 755: 628: 570: 533: 469: 288: 27:Any of certain special normal subgroups of a group 327:of any point acts as the identity on its entire 1479:lies in the principal block if and only if the 1471:lying in the principal block). For a finite, 315:Normal cores are important in the context of 8: 1637:Huppert, Bertram; Blackburn, Norman (1982). 1510: 1504: 1415:, which studies the actions of groups on 1312: 1282: 1273: 1247: 1234: 1228: 1098: 1079: 1066: 1061: 1052: 1032: 1027: 1003: 984: 971: 966: 957: 934: 915: 902: 897: 891: 730: 721: 709: 682: 673: 647: 641: 600: 594: 554: 545:, the 2′-core is often called simply the 511: 505: 452: 446: 267: 262: 250: 228: 214: 211: 195:is the intersection of the conjugates of 80:Learn how and when to remove this message 1451:-block over any field of characteristic 43:This article includes a list of general 1568: 1399:Just as normal cores are important for 790:′-core as the unique largest subnormal 346:is a subgroup whose normal core is the 1179:if and only if it is equal to its own 802:-core as the unique largest subnormal 543:classification of finite simple groups 1610:Doerk, Klaus; Hawkes, Trevor (1992). 1187:-core. A finite group is said to be 7: 392:, though some aspects generalize to 112:. The two most common types are the 1379:-nilpotent if and only if it has a 771:-core is the unique largest normal 1511: 1363:-soluble. Every soluble group is 853:of primes, one defines subgroups O 492:is the largest normal subgroup of 429:. It is the normal core of every 224: 221: 218: 215: 49:it lacks sufficient corresponding 25: 1455:. Also, for a finite group, the 1427:over any field of characteristic 379:Intel Core § 12th generation 1665:A Course in the Theory of Groups 1499:normal subgroup, and is denoted 1439:-block. For a finite group, the 1172:. A finite group is said to be 34: 1671:. Vol. 80 (2nd ed.). 323:, where the normal core of the 180:). More generally, the core of 1528:{\displaystyle O_{\infty }(G)} 1522: 1516: 1335: 1329: 1302: 1299: 1293: 1270: 1264: 1240: 1115: 1112: 1106: 1046: 1017: 1011: 954: 948: 750: 747: 741: 715: 699: 693: 670: 664: 623: 617: 565: 559: 528: 522: 464: 458: 331:. Thus, in case the action is 240: 234: 1: 1669:Graduate Texts in Mathematics 1551:′-core of an insoluble group 1495:is defined to be the largest 1413:modular representation theory 1135:-series is formed by taking 1425:irreducible representations 1205:is the length of its upper 629:{\displaystyle O_{p',p}(G)} 1725: 1594:Cambridge University Press 1431:. For a finite group, the 1375:-constrained. A group is 763:. For a finite group, the 496:whose order is coprime to 376: 104:is any of certain special 1411:′-cores are important in 1351:Every nilpotent group is 1209:-series. A finite group 534:{\displaystyle O_{p'}(G)} 470:{\displaystyle O_{p}(G)} 359:hidden subgroup problem 64:more precise citations. 1529: 1355:-nilpotent, and every 1342: 1122: 757: 630: 572: 535: 471: 290: 168:(or equivalently, the 1661:Robinson, Derek J. S. 1614:Finite Soluble Groups 1530: 1343: 1123: 806:-nilpotent subgroup. 775:-nilpotent subgroup. 758: 631: 573: 536: 472: 394:locally finite groups 357:The solution for the 291: 164:that is contained in 1575:Robinson (1996) p.16 1503: 1387:, which is just its 1367:-soluble, and every 1359:-nilpotent group is 1227: 890: 794:′-subgroup; and the 640: 593: 571:{\displaystyle O(G)} 553: 504: 445: 210: 191: ⊆  1590:Finite Group Theory 1586:Aschbacher, Michael 433:of the group. The 1525: 1371:-soluble group is 1338: 1118: 753: 626: 568: 531: 485:. Similarly, the 467: 344:core-free subgroup 286: 261: 184:with respect to a 1620:Walter de Gruyter 1487:Solvable radicals 441:is often denoted 325:isotropy subgroup 246: 90: 89: 82: 16:(Redirected from 1716: 1694: 1656: 1639:Finite Groups II 1633: 1617: 1606: 1576: 1573: 1545:John G. Thompson 1534: 1532: 1531: 1526: 1515: 1514: 1493:solvable radical 1347: 1345: 1344: 1339: 1328: 1327: 1320: 1292: 1291: 1290: 1277: 1263: 1262: 1255: 1239: 1238: 1164:there is also a 1127: 1125: 1124: 1119: 1105: 1104: 1103: 1102: 1084: 1083: 1071: 1070: 1056: 1045: 1044: 1043: 1042: 1010: 1009: 1008: 1007: 989: 988: 976: 975: 961: 947: 946: 945: 944: 920: 919: 907: 906: 821:-core begin the 762: 760: 759: 754: 740: 739: 738: 725: 714: 713: 692: 691: 690: 677: 663: 662: 655: 635: 633: 632: 627: 616: 615: 608: 577: 575: 574: 569: 540: 538: 537: 532: 521: 520: 519: 500:and is denoted 479:Fitting subgroup 476: 474: 473: 468: 457: 456: 431:Sylow p-subgroup 398:profinite groups 384:In this section 348:trivial subgroup 295: 293: 292: 287: 282: 275: 274: 260: 233: 232: 227: 106:normal subgroups 85: 78: 74: 71: 65: 60:this article by 51:inline citations 38: 37: 30: 21: 1724: 1723: 1719: 1718: 1717: 1715: 1714: 1713: 1699: 1698: 1697: 1683: 1673:Springer-Verlag 1659: 1653: 1643:Springer Verlag 1636: 1630: 1609: 1604: 1584: 1580: 1579: 1574: 1570: 1565: 1506: 1501: 1500: 1489: 1397: 1313: 1308: 1283: 1278: 1248: 1243: 1230: 1225: 1224: 1159: 1145: 1094: 1075: 1062: 1057: 1028: 1023: 999: 980: 967: 962: 930: 911: 898: 893: 888: 887: 878: 877: 867: 860: 852: 842: 835: 786:-subgroup; the 731: 726: 705: 683: 678: 648: 643: 638: 637: 601: 596: 591: 590: 551: 550: 512: 507: 502: 501: 448: 443: 442: 406: 382: 375: 339:of the action. 313: 263: 213: 208: 207: 158:normal subgroup 156:is the largest 150:normal interior 138: 133: 131:The normal core 86: 75: 69: 66: 56:Please help to 55: 39: 35: 28: 23: 22: 15: 12: 11: 5: 1722: 1720: 1712: 1711: 1701: 1700: 1696: 1695: 1681: 1657: 1651: 1634: 1628: 1607: 1602: 1581: 1578: 1577: 1567: 1566: 1564: 1561: 1524: 1521: 1518: 1513: 1509: 1488: 1485: 1396: 1393: 1337: 1334: 1331: 1326: 1323: 1319: 1316: 1311: 1307: 1304: 1301: 1298: 1295: 1289: 1286: 1281: 1276: 1272: 1269: 1266: 1261: 1258: 1254: 1251: 1246: 1242: 1237: 1233: 1213:is said to be 1154: 1139: 1129: 1128: 1117: 1114: 1111: 1108: 1101: 1097: 1093: 1090: 1087: 1082: 1078: 1074: 1069: 1065: 1060: 1055: 1051: 1048: 1041: 1038: 1035: 1031: 1026: 1022: 1019: 1016: 1013: 1006: 1002: 998: 995: 992: 987: 983: 979: 974: 970: 965: 960: 956: 953: 950: 943: 940: 937: 933: 929: 926: 923: 918: 914: 910: 905: 901: 896: 872: 865: 858: 854: 847: 840: 833: 752: 749: 746: 743: 737: 734: 729: 724: 720: 717: 712: 708: 704: 701: 698: 695: 689: 686: 681: 676: 672: 669: 666: 661: 658: 654: 651: 646: 636:is defined by 625: 622: 619: 614: 611: 607: 604: 599: 567: 564: 561: 558: 530: 527: 524: 518: 515: 510: 466: 463: 460: 455: 451: 405: 402: 388:will denote a 374: 367: 354:group action. 312: 309: 303: =  297: 296: 285: 281: 278: 273: 270: 266: 259: 256: 253: 249: 245: 242: 239: 236: 231: 226: 223: 220: 217: 152:of a subgroup 137: 134: 132: 129: 96:, a branch of 88: 87: 42: 40: 33: 26: 24: 14: 13: 10: 9: 6: 4: 3: 2: 1721: 1710: 1707: 1706: 1704: 1692: 1688: 1684: 1682:0-387-94461-3 1678: 1674: 1670: 1666: 1662: 1658: 1654: 1652:0-387-10632-4 1648: 1644: 1640: 1635: 1631: 1629:3-11-012892-6 1625: 1621: 1616: 1615: 1608: 1605: 1603:0-521-78675-4 1599: 1595: 1591: 1587: 1583: 1582: 1572: 1569: 1562: 1560: 1558: 1554: 1550: 1546: 1542: 1538: 1519: 1507: 1498: 1494: 1486: 1484: 1482: 1478: 1474: 1470: 1466: 1462: 1458: 1454: 1450: 1446: 1442: 1438: 1434: 1430: 1426: 1422: 1418: 1417:vector spaces 1414: 1410: 1406: 1402: 1401:group actions 1394: 1392: 1390: 1386: 1384: 1378: 1374: 1370: 1366: 1362: 1358: 1354: 1349: 1332: 1324: 1321: 1317: 1314: 1309: 1305: 1296: 1287: 1284: 1279: 1274: 1267: 1259: 1256: 1252: 1249: 1244: 1235: 1231: 1222: 1218: 1217: 1216:p-constrained 1212: 1208: 1204: 1202: 1198:-series; its 1197: 1193: 1191: 1186: 1182: 1178: 1176: 1171: 1169: 1163: 1158: 1153: 1149: 1143: 1138: 1134: 1109: 1099: 1095: 1091: 1088: 1085: 1080: 1076: 1072: 1067: 1063: 1058: 1053: 1049: 1039: 1036: 1033: 1029: 1024: 1020: 1014: 1004: 1000: 996: 993: 990: 985: 981: 977: 972: 968: 963: 958: 951: 941: 938: 935: 931: 927: 924: 921: 916: 912: 908: 903: 899: 894: 886: 885: 884: 882: 875: 871: 864: 857: 850: 846: 839: 832: 828: 826: 820: 816: 812: 807: 805: 801: 797: 793: 789: 785: 781: 776: 774: 770: 766: 744: 735: 732: 727: 722: 718: 710: 706: 702: 696: 687: 684: 679: 674: 667: 659: 656: 652: 649: 644: 620: 612: 609: 605: 602: 597: 588: 586: 582: 562: 556: 548: 544: 525: 516: 513: 508: 499: 495: 491: 489: 484: 480: 461: 453: 449: 440: 436: 432: 428: 426: 421: 419: 414: 411: 403: 401: 399: 395: 391: 387: 380: 372: 368: 366: 364: 360: 355: 353: 349: 345: 340: 338: 334: 330: 326: 322: 318: 317:group actions 310: 308: 306: 302: 283: 279: 276: 271: 268: 264: 257: 254: 251: 247: 243: 237: 229: 206: 205: 204: 202: 198: 194: 190: 187: 183: 179: 175: 171: 167: 163: 159: 155: 151: 147: 143: 135: 130: 128: 126: 124: 119: 115: 111: 107: 103: 99: 95: 84: 81: 73: 70:December 2023 63: 59: 53: 52: 46: 41: 32: 31: 19: 1709:Group theory 1664: 1638: 1613: 1589: 1571: 1556: 1552: 1548: 1540: 1536: 1492: 1490: 1480: 1476: 1472: 1468: 1464: 1460: 1456: 1452: 1448: 1444: 1440: 1436: 1432: 1428: 1420: 1408: 1404: 1398: 1395:Significance 1388: 1382: 1380: 1376: 1372: 1368: 1364: 1360: 1356: 1352: 1350: 1220: 1219:for a prime 1214: 1210: 1206: 1200: 1199: 1195: 1189: 1188: 1184: 1180: 1174: 1173: 1167: 1161: 1156: 1151: 1147: 1141: 1136: 1132: 1130: 880: 873: 869: 862: 855: 848: 844: 837: 830: 829:. For sets 824: 822: 818: 814: 810: 808: 803: 799: 795: 791: 787: 783: 779: 777: 772: 768: 764: 584: 580: 579: 549:and denoted 546: 497: 493: 487: 486: 483:finite group 438: 434: 424: 417: 416: 412: 407: 390:finite group 385: 383: 370: 356: 343: 341: 314: 311:Significance 304: 300: 298: 200: 196: 192: 188: 181: 177: 170:intersection 165: 161: 153: 149: 145: 141: 140:For a group 139: 127:of a group. 122: 121: 113: 101: 94:group theory 91: 76: 67: 48: 1407:-cores and 1385:-complement 146:normal core 114:normal core 98:mathematics 62:introducing 18:Normal core 1691:0836.20001 1563:References 1539:′-core of 1177:-nilpotent 1131:The upper 589:, denoted 404:Definition 333:transitive 174:conjugates 136:Definition 45:references 1512:∞ 1403:on sets, 1306:⊆ 1096:π 1089:… 1077:π 1064:π 1030:π 1001:π 994:… 982:π 969:π 932:π 925:… 913:π 900:π 437:-core of 427:-subgroup 269:− 255:∈ 248:⋂ 1703:Category 1663:(1996). 1588:(2000), 1497:solvable 1391:′-core. 1318:′ 1288:′ 1253:′ 1192:-soluble 736:′ 688:′ 653:′ 606:′ 517:′ 352:faithful 120:and the 118:subgroup 1555:as the 1381:normal 1203:-length 1170:-series 868:, ..., 843:, ..., 827:-series 396:and to 363:abelian 361:in the 203:, i.e. 172:of the 58:improve 1689:  1679:  1649:  1626:  1600:  1419:. The 1166:lower 1150:′ and 883:) by: 823:upper 813:′ and 490:′-core 415:, the 408:For a 337:kernel 199:under 186:subset 144:, the 47:, but 587:-core 481:of a 420:-core 410:prime 373:-core 329:orbit 125:-core 116:of a 110:group 108:of a 1677:ISBN 1647:ISBN 1624:ISBN 1598:ISBN 809:The 778:The 547:core 369:The 321:sets 102:core 100:, a 1687:Zbl 1223:if 319:on 176:of 160:of 148:or 92:In 1705:: 1685:. 1675:. 1667:. 1645:. 1641:. 1622:. 1618:. 1596:, 1592:, 1459:′, 1443:′, 1348:. 1183:′, 1162:p; 1160:= 1146:= 1144:−1 876:+1 861:, 851:+1 836:, 817:′, 798:′, 767:′, 583:′, 400:. 342:A 244::= 1693:. 1655:. 1632:. 1557:p 1553:G 1549:p 1541:G 1537:p 1523:) 1520:G 1517:( 1508:O 1481:p 1477:p 1473:p 1469:p 1465:p 1461:p 1457:p 1453:p 1449:p 1445:p 1441:p 1437:p 1433:p 1429:p 1421:p 1409:p 1405:p 1389:p 1383:p 1377:p 1373:p 1369:p 1365:p 1361:p 1357:p 1353:p 1336:) 1333:G 1330:( 1325:p 1322:, 1315:p 1310:O 1303:) 1300:) 1297:G 1294:( 1285:p 1280:O 1275:/ 1271:) 1268:G 1265:( 1260:p 1257:, 1250:p 1245:O 1241:( 1236:G 1232:C 1221:p 1211:G 1207:p 1201:p 1196:p 1190:p 1185:p 1181:p 1175:p 1168:p 1157:i 1155:2 1152:π 1148:p 1142:i 1140:2 1137:π 1133:p 1116:) 1113:) 1110:G 1107:( 1100:n 1092:, 1086:, 1081:2 1073:, 1068:1 1059:O 1054:/ 1050:G 1047:( 1040:1 1037:+ 1034:n 1025:O 1021:= 1018:) 1015:G 1012:( 1005:n 997:, 991:, 986:2 978:, 973:1 964:O 959:/ 955:) 952:G 949:( 942:1 939:+ 936:n 928:, 922:, 917:2 909:, 904:1 895:O 881:G 879:( 874:n 870:π 866:2 863:π 859:1 856:π 849:n 845:π 841:2 838:π 834:1 831:π 825:p 819:p 815:p 811:p 804:p 800:p 796:p 792:p 788:p 784:p 780:p 773:p 769:p 765:p 751:) 748:) 745:G 742:( 733:p 728:O 723:/ 719:G 716:( 711:p 707:O 703:= 700:) 697:G 694:( 685:p 680:O 675:/ 671:) 668:G 665:( 660:p 657:, 650:p 645:O 624:) 621:G 618:( 613:p 610:, 603:p 598:O 585:p 581:p 566:) 563:G 560:( 557:O 529:) 526:G 523:( 514:p 509:O 498:p 494:G 488:p 465:) 462:G 459:( 454:p 450:O 439:G 435:p 425:p 418:p 413:p 386:G 381:. 371:p 305:G 301:S 284:. 280:s 277:H 272:1 265:s 258:S 252:s 241:) 238:H 235:( 230:S 225:e 222:r 219:o 216:C 201:S 197:H 193:G 189:S 182:H 178:H 166:H 162:G 154:H 142:G 123:p 83:) 77:( 72:) 68:( 54:. 20:)

Index

Normal core
references
inline citations
improve
introducing
Learn how and when to remove this message
group theory
mathematics
normal subgroups
group
subgroup
normal subgroup
intersection
conjugates
subset
group actions
sets
isotropy subgroup
orbit
transitive
kernel
trivial subgroup
faithful
hidden subgroup problem
abelian
Intel Core § 12th generation
finite group
locally finite groups
profinite groups
prime

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