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Fitting length

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Given a solvable group, the lower Fitting series is a "coarser" division than the lower central series: the lower Fitting series gives a series for the whole group, while the lower central series descends only from the whole group to the first term of the Fitting series.
174:. These correspond to the center and the commutator subgroup (for upper and lower central series, respectively). These do not hold for infinite groups, so for the sequel, assume all groups to be finite. 385:
The lower Fitting series descends most quickly amongst all Fitting chains, and the upper Fitting series ascends most quickly amongst all Fitting chains. Explicitly: For every Fitting chain, 1 =
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do for nilpotent groups, Fitting series do for solvable groups. A group has a central series if and only if it is nilpotent, and a Fitting series if and only if it is solvable.
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Combining the lower Fitting series and lower central series on a solvable group yields a series with coarse and fine divisions, like the coarse and fine marks on a ruler.
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For a solvable group, the length of the lower Fitting series is equal to length of the upper Fitting series, and this common length is the Fitting length of the group.
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Proceeding in this way (lifting the lower central series for each quotient of the Fitting series) yields a subnormal series:
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The lower Fitting series is a Fitting chain if and only if it eventually reaches the trivial subgroup, if and only if
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The successive quotients are abelian, showing the equivalence between being solvable and having a Fitting series.
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The upper Fitting series is a Fitting chain if and only if it eventually reaches the whole group,
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of the previous one, and such that the quotients of successive terms are nilpotent groups.
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is defined to be the smallest possible length of a Fitting chain, if one exists.
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including both the whole group and the trivial group, such that each is a
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on five or more points has no Fitting chain at all, not being solvable.
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A nontrivial group has Fitting length 1 if and only if it is nilpotent.
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copies of the symmetric group on three points has Fitting length 2
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and is a lift of the lower central series for the first quotient
305:)). It is a descending nilpotent series, at each step taking the 225:)). It is an ascending nilpotent series, at each step taking the 181:
of a finite group is the sequence of characteristic subgroups
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while the lower central series subdivides the first step,
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Connection between central series and Fitting series
360:A group has a Fitting chain if and only if it is 16:Measurement in group theory algebra mathematics 8: 51:, due to his investigations of nilpotent 634:like the coarse and fine divisions on a 94:. In other words, a finite sequence of 463: 7: 166:), the intersection of the (finite) 493:The lower Fitting series proceeds: 462:More information can be found in ( 14: 675:(in German), Berlin, New York: 342:The iterated wreath product of 323:symmetric group on three points 330:symmetric group on four points 121:Upper and lower Fitting series 23:, specifically in the area of 1: 47:. The concept is named after 734:Encyclopedia of Mathematics 727:Turull, Alexandre (2001) , 716:Encyclopedia of Mathematics 709:Turull, Alexandre (2001) , 771: 242:characteristic subgroups 564:, which is nilpotent. 479: 170:, which is called the 477: 332:has Fitting length 3. 325:has Fitting length 2. 39:) measures how far a 234:lower Fitting series 179:upper Fitting series 168:lower central series 131:lower central series 127:upper central series 309:possible subgroup. 240:is the sequence of 229:possible subgroup. 140:For a finite group 133:are extremal among 480: 236:of a finite group 172:nilpotent residual 686:978-3-540-03825-2 466:, Kap. III, §4). 378:, if and only if 762: 741: 723: 711:"Fitting length" 705: 673:Endliche Gruppen 146:Fitting subgroup 111:nilpotent length 85:subnormal series 77: 76: 75:nilpotent series 53:normal subgroups 37:nilpotent length 770: 769: 765: 764: 763: 761: 760: 759: 755:Subgroup series 745: 744: 729:"Fitting chain" 726: 708: 687: 677:Springer-Verlag 667: 664: 647: 629: 622: 615: 608: 601: 594: 587: 580: 563: 556: 545: 538: 531: 513: 506: 472: 454: 437: 420: 412:, one has that 407: 398: 391: 357: 337:symmetric group 315: 300: 291: 280: 262: 251: 161: 123: 100:normal subgroup 74: 73: 61: 17: 12: 11: 5: 768: 766: 758: 757: 747: 746: 743: 742: 724: 706: 685: 663: 660: 659: 658: 653: 651:Central series 646: 643: 632: 631: 627: 620: 613: 606: 599: 592: 585: 578: 561: 554: 548: 547: 543: 536: 529: 516: 515: 511: 504: 484:central series 471: 468: 460: 459: 456: 446: 433: 416: 403: 396: 389: 383: 372: 365: 356: 353: 352: 351: 340: 333: 326: 319: 314: 311: 296: 289: 275: 260: 256:) defined by 247: 159: 135:central series 122: 119: 107:Fitting length 69:Fitting series 60: 57: 43:is from being 41:solvable group 33:Fitting length 15: 13: 10: 9: 6: 4: 3: 2: 767: 756: 753: 752: 750: 740: 736: 735: 730: 725: 722: 718: 717: 712: 707: 704: 700: 696: 692: 688: 682: 678: 674: 670: 666: 665: 661: 657: 654: 652: 649: 648: 644: 642: 639: 637: 626: 619: 612: 605: 598: 591: 584: 577: 573: 570: 569: 568: 565: 560: 553: 542: 535: 528: 524: 521: 520: 519: 510: 503: 499: 496: 495: 494: 491: 487: 485: 476: 469: 467: 465: 457: 453: 449: 445: 441: 436: 432: 428: 424: 419: 415: 411: 406: 402: 395: 388: 384: 381: 377: 373: 370: 366: 363: 359: 358: 354: 349: 345: 341: 338: 334: 331: 327: 324: 320: 317: 316: 312: 310: 308: 304: 299: 295: 288: 284: 278: 274: 270: 266: 259: 255: 250: 246: 243: 239: 235: 230: 228: 224: 220: 216: 212: 208: 204: 200: 196: 192: 189:) defined by 188: 184: 180: 175: 173: 169: 165: 158: 154: 150: 147: 143: 138: 136: 132: 128: 120: 118: 116: 112: 108: 103: 101: 97: 93: 90: 86: 82: 78: 70: 66: 65:Fitting chain 58: 56: 54: 50: 46: 42: 38: 34: 30: 26: 22: 732: 714: 672: 656:3-step group 640: 633: 624: 617: 610: 603: 596: 589: 582: 575: 571: 566: 558: 551: 549: 540: 533: 526: 522: 517: 508: 501: 497: 492: 488: 481: 464:Huppert 1967 461: 451: 447: 443: 439: 434: 430: 426: 422: 417: 413: 409: 404: 400: 393: 386: 382:is solvable. 379: 375: 371:is solvable. 368: 347: 343: 306: 302: 297: 293: 286: 282: 276: 272: 268: 264: 257: 253: 248: 244: 237: 233: 231: 226: 222: 218: 214: 210: 206: 202: 198: 194: 190: 186: 182: 178: 176: 163: 156: 152: 148: 141: 139: 125:Just as the 124: 110: 106: 104: 72: 68: 64: 62: 49:Hans Fitting 36: 32: 29:group theory 18: 669:Huppert, B. 197:) = 1, and 21:mathematics 662:References 355:Properties 59:Definition 739:EMS Press 721:EMS Press 96:subgroups 92:quotients 89:nilpotent 45:nilpotent 27:known as 749:Category 671:(1967), 645:See also 514:⊵ ⋯ ⊵ 1, 429:), and 362:solvable 313:Examples 79:) for a 695:0224703 307:minimal 227:maximal 25:algebra 703:527050 701:  693:  683:  623:⊵ ⋯ ⊵ 609:⊵ ⋯ ⊵ 588:⊵ ⋯ ⊵ 539:⊵ ⋯ ⊵ 399:⊲ … ⊲ 271:, and 144:, the 31:, the 636:ruler 482:What 115:group 113:of a 87:with 83:is a 81:group 699:OCLC 681:ISBN 630:= 1, 442:) ≤ 335:The 328:The 321:The 285:) = 267:) = 232:The 213:) = 177:The 129:and 105:The 67:(or 35:(or 621:2,1 607:1,2 600:1,1 423:Fit 219:Fit 217:(G/ 215:Fit 207:Fit 199:Fit 191:Fit 183:Fit 149:Fit 109:or 71:or 19:In 751:: 737:, 731:, 719:, 713:, 697:, 691:MR 689:, 679:, 638:. 616:= 602:⊵ 595:= 581:⊵ 574:= 532:⊵ 525:= 507:⊵ 500:= 421:≤ 408:= 392:⊲ 279:+1 205:)/ 63:A 55:. 628:n 625:F 618:F 614:2 611:F 604:F 597:F 593:1 590:F 586:2 583:G 579:1 576:G 572:G 562:1 559:F 557:/ 555:0 552:F 546:, 544:1 541:F 537:2 534:G 530:1 527:G 523:G 512:1 509:F 505:0 502:F 498:G 455:. 452:i 450:− 448:n 444:H 440:G 438:( 435:i 431:F 427:G 425:( 418:i 414:H 410:G 405:n 401:H 397:1 394:H 390:0 387:H 380:G 376:G 369:G 364:. 350:. 348:n 344:n 303:G 301:( 298:n 294:F 292:( 290:∞ 287:γ 283:G 281:( 277:n 273:F 269:G 265:G 263:( 261:0 258:F 254:G 252:( 249:n 245:F 238:G 223:G 221:( 211:G 209:( 203:G 201:( 195:G 193:( 187:G 185:( 164:H 162:( 160:∞ 157:γ 153:H 151:( 142:H

Index

mathematics
algebra
group theory
solvable group
nilpotent
Hans Fitting
normal subgroups
group
subnormal series
nilpotent
quotients
subgroups
normal subgroup
group
upper central series
lower central series
central series
Fitting subgroup
lower central series
nilpotent residual
characteristic subgroups
symmetric group on three points
symmetric group on four points
symmetric group
solvable
Huppert 1967

central series
ruler
Central series

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