The existence of designs via iterative absorption

In a recent breakthrough, Keevash proved the Existence conjecture for combinatorial designs, which has its roots in the 19th century. We give a new proof, based on the method of iterative absorption. Our main result concerns $K^{(r)}_{q}$-decompositions of hypergraphs whose clique distribution fulfils certain uniformity criteria. These criteria offer considerable flexibility. This enables us to strengthen the results of Keevash as well as to derive a number of new results, for example a resilience version and minimum degree version.

[1]  Benny Sudakov,et al.  Local resilience of graphs , 2007, Random Struct. Algorithms.

[2]  Daniela Kühn,et al.  Fractional clique decompositions of dense graphs and hypergraphs , 2015, J. Comb. Theory, Ser. B.

[3]  Daniela Kühn,et al.  Edge‐disjoint Hamilton cycles in random graphs , 2011, Random Struct. Algorithms.

[4]  Deryk Osthus,et al.  Hypergraph $F$-designs for arbitrary $F$ , 2017, 1706.01800.

[5]  Jack E. Graver,et al.  The Module Structure of Integral Designs , 1973, J. Comb. Theory, Ser. A.

[6]  Vojtech Rödl,et al.  A Dirac-Type Theorem for 3-Uniform Hypergraphs , 2006, Combinatorics, Probability and Computing.

[7]  Peter J. Dukes,et al.  Fractional triangle decompositions of dense $3$-partite graphs , 2015, Journal of Combinatorics.

[8]  Svante Janson,et al.  Random graphs , 2000, ZOR Methods Model. Oper. Res..

[9]  Daniela Kühn,et al.  Edge-decompositions of graphs with high minimum degree , 2014, Electron. Notes Discret. Math..

[10]  W. T. Gowers,et al.  Combinatorial theorems in sparse random sets , 2010, 1011.4310.

[11]  Michael Krivelevich,et al.  Triangle Factors in Random Graphs , 1997, Combinatorics, Probability and Computing.

[12]  Vojtech Rödl,et al.  Note on Independent Sets in Steiner Systems , 1994, Random Struct. Algorithms.

[13]  Peter Keevash Counting designs , 2015 .

[14]  Richard Montgomery,et al.  Fractional Clique Decompositions of Dense Partite Graphs , 2016, Combinatorics, Probability and Computing.

[15]  Hiêp Hàn,et al.  On Perfect Matchings in Uniform Hypergraphs with Large Minimum Vertex Degree , 2009, SIAM J. Discret. Math..

[16]  Luc Teirlinck Non-trivial t-designs without repeated blocks exist for all t , 1987, Discret. Math..

[17]  Darryn Bryant,et al.  A proof of Lindner's conjecture on embeddings of partial Steiner triple systems , 2009 .

[18]  D. Kuhn,et al.  Optimal packings of bounded degree trees , 2016, Journal of the European Mathematical Society.

[19]  Daniela Kühn,et al.  Clique decompositions of multipartite graphs and completion of Latin squares , 2016, J. Comb. Theory, Ser. A.

[20]  François Dross,et al.  Fractional Triangle Decompositions in Graphs with Large Minimum Degree , 2015, SIAM J. Discret. Math..

[21]  Rajeev Raman,et al.  The Power of Collision: Randomized Parallel Algorithms for Chaining and Integer Sorting , 1990, FSTTCS.

[22]  Noga Alon,et al.  On a Hypergraph Matching Problem , 2005, Graphs Comb..

[23]  Jeong Han Kim,et al.  Nearly perfect matchings in regular simple hypergraphs , 1997 .

[24]  M. Schacht Extremal results for random discrete structures , 2016, 1603.00894.

[25]  Richard M. Wilson,et al.  An Existence Theory for Pairwise Balanced Designs I. Composition Theorems and Morphisms , 1972, J. Comb. Theory, Ser. A.

[26]  Alan M. Frieze,et al.  Random graphs , 2006, SODA '06.

[27]  Peter Keevash The existence of designs , 2014, 1401.3665.

[28]  B. Sudakov,et al.  A Construction of Almost Steiner Systems , 2013, 1303.4065.

[29]  Joel H. Spencer,et al.  Asymptotic behavior of the chromatic index for hypergraphs , 1989, J. Comb. Theory, Ser. A.

[30]  Raphael Yuster,et al.  Combinatorial and computational aspects of graph packing and graph decomposition , 2007, Comput. Sci. Rev..

[31]  Van H. Vu,et al.  New bounds on nearly perfect matchings in hypergraphs: Higher codegrees do help , 2000, Random Struct. Algorithms.

[32]  C. Colbourn,et al.  Handbook of Combinatorial Designs , 2006 .

[33]  Shachar Lovett,et al.  Probabilistic existence of rigid combinatorial structures , 2012, STOC '12.

[34]  Daniela Kühn,et al.  Hamilton decompositions of regular expanders: a proof of Kelly's conjecture for large tournaments , 2012, ArXiv.

[35]  Richard M. Wilson,et al.  An Existence Theory for Pairwise Balanced Designs II. The Structure of PBD-Closed Sets and the Existence Conjectures , 1972, J. Comb. Theory A.

[36]  Alexandr V. Kostochka,et al.  On independent sets in hypergraphs , 2011, Random Struct. Algorithms.

[37]  Richard M. Wilson,et al.  An Existence Theory for Pairwise Balanced Designs II. The Structure of PBD-Closed Sets and the Existence Conjectures , 1972, J. Comb. Theory, Ser. A.

[38]  Vojtech Rödl,et al.  Dirac-Type Questions For Hypergraphs — A Survey (Or More Problems For Endre To Solve) , 2010 .

[39]  T. Gustavsson Decompositions of large graphs and digraphs with high minimum degree , 1991 .

[40]  Vojtech Rödl,et al.  On a Packing and Covering Problem , 1985, Eur. J. Comb..

[41]  Yi Zhao,et al.  Recent advances on Dirac-type problems for hypergraphs , 2015, 1508.06170.