English

The existence of designs

Combinatorics 2024-11-28 v4

Abstract

We prove the existence conjecture for combinatorial designs, answering a question of Steiner from 1853. More generally, we show that the natural divisibility conditions are sufficient for clique decompositions of simplicial complexes that satisfy a certain pseudorandomness condition. As a further generalisation, we obtain the same conclusion only assuming an extendability property and the existence of a robust fractional clique decomposition.

Keywords

Cite

@article{arxiv.1401.3665,
  title  = {The existence of designs},
  author = {Peter Keevash},
  journal= {arXiv preprint arXiv:1401.3665},
  year   = {2024}
}

Comments

Version 4 (the decennial edition) incorporates referee comments, additional exposition and a brief review of subsequent work

R2 v1 2026-06-22T02:46:22.767Z