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Baranyai's theorem

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20: 290: 442: 97: 176: 140: 361: 589: 334: 462: 381: 186:
vertices forms a hyperedge; a 1-factor of this hypergraph is a set of hyperedges that touches each vertex exactly once, or equivalently a
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colors so that the edges of each color form a perfect matching. Baranyai's theorem says that we can do this whenever
562: 52: 575: 493: 485: 607: 143: 70: 187: 149: 113: 583: 529: 511: = 3 case was established by R. Peltesohn in 1936. The general case was proved by 489: 28: 339: 313: 537: 525: 512: 477: 447: 366: 48: 24: 19: 601: 550: 481: 40: 554: 533: 544:, Colloquia Math. Soc. János Bolyai, vol. 10, North-Holland, pp. 91–107 108: 56: 496:, and its solution was already known in the 19th century. The case that 528:(1975), "On the factorization of the complete uniform hypergraph", in 18: 16:
Theorem that deals with the decompositions of complete hypergraphs
285:{\displaystyle {\binom {k}{r}}{\frac {r}{k}}={\binom {k-1}{r-1}}} 198:
vertices of the hypergraph may be partitioned into subsets of
476: = 2 case can be rephrased as stating that every 296:-element subset appears in exactly one of the partitions. 488:, or equivalently that its edges may be partitioned into 542:
Infinite and Finite Sets, Proc. Coll. Keszthely, 1973
450: 389: 369: 342: 316: 208: 152: 116: 73: 456: 436: 375: 355: 328: 284: 170: 134: 91: 437:{\displaystyle {\binom {n}{2}}{\frac {2}{n}}=n-1} 406: 393: 276: 247: 225: 212: 383:vertices, and we wish to color the edges with 8: 588:: CS1 maint: location missing publisher ( 572:Das Turnierproblem für Spiele zu je dreien 190:of the vertices into subsets of size  449: 412: 405: 392: 390: 388: 368: 347: 341: 315: 275: 246: 244: 231: 224: 211: 209: 207: 162: 157: 151: 126: 121: 115: 72: 292:different ways, in such a way that each 480:with an even number of vertices has an 67:The statement of the result is that if 581: 7: 194:. Thus, the theorem states that the 35: = 2 of Baranyai's theorem 182:vertices, in which every subset of 484:whose number of colors equals its 397: 251: 216: 14: 1: 492:. It may be used to schedule 27:on 8 vertices into 7 colors ( 92:{\displaystyle 2\leq r<k} 336:, we have a complete graph 47:(proved by and named after 629: 563:Cambridge University Press 613:Theorems in combinatorics 559:A Course in Combinatorics 171:{\displaystyle K_{r}^{k}} 135:{\displaystyle K_{r}^{k}} 63:Statement of the theorem 494:round-robin tournaments 576:Inaugural dissertation 570:Peltesohn, R. (1936), 458: 438: 377: 357: 330: 286: 172: 136: 93: 36: 459: 439: 378: 358: 356:{\displaystyle K_{n}} 331: 287: 178:is a hypergraph with 173: 137: 94: 22: 448: 387: 367: 340: 314: 310:In the special case 206: 150: 114: 107:, then the complete 71: 329:{\displaystyle r=2} 167: 131: 454: 434: 373: 353: 326: 282: 168: 153: 132: 117: 89: 45:Baranyai's theorem 37: 490:perfect matchings 457:{\displaystyle n} 420: 404: 376:{\displaystyle n} 274: 239: 223: 99:are integers and 51:) deals with the 29:perfect matchings 23:A partition of a 620: 593: 587: 579: 565: 561:(2nd ed.), 545: 463: 461: 460: 455: 443: 441: 440: 435: 421: 413: 411: 410: 409: 396: 382: 380: 379: 374: 362: 360: 359: 354: 352: 351: 335: 333: 332: 327: 306: 291: 289: 288: 283: 281: 280: 279: 273: 262: 250: 240: 232: 230: 229: 228: 215: 177: 175: 174: 169: 166: 161: 142:decomposes into 141: 139: 138: 133: 130: 125: 98: 96: 95: 90: 628: 627: 623: 622: 621: 619: 618: 617: 598: 597: 580: 569: 551:van Lint, J. H. 549: 524: 521: 470: 446: 445: 391: 385: 384: 365: 364: 343: 338: 337: 312: 311: 308: 301: 263: 252: 245: 210: 204: 203: 148: 147: 112: 111: 69: 68: 65: 17: 12: 11: 5: 626: 624: 616: 615: 610: 600: 599: 596: 595: 567: 547: 520: 517: 513:Zsolt Baranyai 504:is also easy. 500: = 2 478:complete graph 469: 466: 453: 433: 430: 427: 424: 419: 416: 408: 403: 400: 395: 372: 350: 346: 325: 322: 319: 307: 298: 278: 272: 269: 266: 261: 258: 255: 249: 243: 238: 235: 227: 222: 219: 214: 165: 160: 156: 129: 124: 120: 88: 85: 82: 79: 76: 64: 61: 53:decompositions 49:Zsolt Baranyai 25:complete graph 15: 13: 10: 9: 6: 4: 3: 2: 625: 614: 611: 609: 606: 605: 603: 591: 585: 577: 573: 568: 564: 560: 556: 555:Wilson, R. M. 552: 548: 543: 539: 535: 531: 527: 526:Baranyai, Zs. 523: 522: 518: 516: 514: 510: 505: 503: 499: 495: 491: 487: 483: 482:edge coloring 479: 475: 467: 465: 451: 431: 428: 425: 422: 417: 414: 401: 398: 370: 348: 344: 323: 320: 317: 304: 299: 297: 295: 270: 267: 264: 259: 256: 253: 241: 236: 233: 220: 217: 201: 197: 193: 189: 185: 181: 163: 158: 154: 145: 127: 122: 118: 110: 106: 102: 86: 83: 80: 77: 74: 62: 60: 58: 54: 50: 46: 43:mathematics, 42: 41:combinatorial 34: 30: 26: 21: 571: 558: 541: 508: 506: 501: 497: 473: 471: 309: 302: 293: 202:vertices in 199: 195: 191: 183: 179: 104: 100: 66: 55:of complete 44: 38: 32: 31:), the case 608:Hypergraphs 57:hypergraphs 602:Categories 538:Sós, V. T. 530:Hajnal, A. 519:References 109:hypergraph 515:in 1975. 464:is even. 429:− 300:The case 268:− 257:− 188:partition 144:1-factors 78:≤ 584:citation 578:, Berlin 557:(2001), 540:(eds.), 534:Rado, R. 103:divides 468:History 486:degree 590:link 507:The 472:The 84:< 363:on 305:= 2 39:In 604:: 586:}} 582:{{ 574:, 553:; 536:; 532:; 146:. 59:. 594:. 592:) 566:. 546:. 509:r 502:r 498:k 474:r 452:n 432:1 426:n 423:= 418:n 415:2 407:) 402:2 399:n 394:( 371:n 349:n 345:K 324:2 321:= 318:r 303:r 294:r 277:) 271:1 265:r 260:1 254:k 248:( 242:= 237:k 234:r 226:) 221:r 218:k 213:( 200:r 196:k 192:r 184:r 180:k 164:k 159:r 155:K 128:k 123:r 119:K 105:k 101:r 87:k 81:r 75:2 33:r

Index


complete graph
perfect matchings
combinatorial
Zsolt Baranyai
decompositions
hypergraphs
hypergraph
1-factors
partition
complete graph
edge coloring
degree
perfect matchings
round-robin tournaments
Zsolt Baranyai
Baranyai, Zs.
Hajnal, A.
Rado, R.
Sós, V. T.
van Lint, J. H.
Wilson, R. M.
Cambridge University Press
Inaugural dissertation
citation
link
Categories
Hypergraphs
Theorems in combinatorics

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