English

Regular Intersecting Families

Combinatorics 2019-07-02 v3 Discrete Mathematics

Abstract

We call a family of sets intersecting, if any two sets in the family intersect. In this paper we investigate intersecting families F\mathcal{F} of kk-element subsets of [n]:={1,,n},[n]:=\{1,\ldots, n\}, such that every element of [n][n] lies in the same (or approximately the same) number of members of F\mathcal{F}. In particular, we show that we can guarantee F=o((n1k1))|\mathcal{F}| = o({n-1\choose k-1}) if and only if k=o(n)k=o(n).

Keywords

Cite

@article{arxiv.1709.10462,
  title  = {Regular Intersecting Families},
  author = {Ferdinand Ihringer and Andrey Kupavskii},
  journal= {arXiv preprint arXiv:1709.10462},
  year   = {2019}
}

Comments

15 pages, accepted version

R2 v1 2026-06-22T21:59:05.351Z