English

Odd-Sunflowers

Combinatorics 2024-03-22 v2

Abstract

Extending the notion of sunflowers, we call a family of at least two sets an odd-sunflower if every element of the underlying set is contained in an odd number of sets or in none of them. It follows from the Erd\H os--Szemer\'edi conjecture, recently proved by Naslund and Sawin, that there is a constant μ<2\mu<2 such that every family of subsets of an nn-element set that contains no odd-sunflower consists of at most μn\mu^n sets. We construct such families of size at least 1.5021n1.5021^n. We also characterize minimal odd-sunflowers of triples.

Keywords

Cite

@article{arxiv.2310.16701,
  title  = {Odd-Sunflowers},
  author = {Peter Frankl and János Pach and Dömötör Pálvölgyi},
  journal= {arXiv preprint arXiv:2310.16701},
  year   = {2024}
}
R2 v1 2026-06-28T13:01:41.626Z