English

More on the Erd\H os--Kleitman problem on matchings in set families

Combinatorics 2026-05-07 v1 Discrete Mathematics

Abstract

Let e(n,s)e(n,s) denote the maximum size of a family F\mathcal{F} of subsets of an nn-element set that contains no ss pairwise disjoint members. In 1968, answering a question of Erd\H{o}s, Kleitman determined e(sm1,s)e(sm-1,s) and e(sm,s)e(sm,s) for all integers m,s1m,s\ge 1. Half a century later, Frankl and Kupavskii determined e(s(m+1),s)e(s(m+1)-\ell, s) for s3m+3\ell \leq \frac{s-3}{m+3}. They showed that the corresponding extremal example is closely connected with the extremal example for the Erd\H{o}s Matching Conjecture, and conjectured that the same remains true for all s/2\ell \leq s/2. In this paper, we prove an approximate version of their conjecture for ss0(m)s\ge s_0(m).

Keywords

Cite

@article{arxiv.2605.04379,
  title  = {More on the Erd\H os--Kleitman problem on matchings in set families},
  author = {Andrey Kupavskii and Georgy Sokolov},
  journal= {arXiv preprint arXiv:2605.04379},
  year   = {2026}
}