English

The connection between the chromatic numbers of a hypergraph and its $1$-intersection graph

Combinatorics 2024-06-19 v1

Abstract

A well known problem from an excellent book of Lov\'asz states that any hypergraph with the property that no pair of hyperedges intersect in exactly one vertex can be properly 2-colored. Motivated by this as well as recent works of Keszegh and of Gy\'arf\'as et al we study the 11-intersection graph of a hypergraph. The 11-intersection graph encodes those pairs of hyperedges in a hypergraph that intersect in exactly one vertex. We prove for k{2,4}k\in\{2,4\} that all hypergraphs whose 11-intersection graph is kk-partite can be properly kk-colored.

Keywords

Cite

@article{arxiv.2406.12118,
  title  = {The connection between the chromatic numbers of a hypergraph and its $1$-intersection graph},
  author = {Zoltán L. Blázsik and Nathan W. Lemons},
  journal= {arXiv preprint arXiv:2406.12118},
  year   = {2024}
}
R2 v1 2026-06-28T17:09:35.893Z