English

Note on polychromatic coloring of hereditary hypergraph families II

Combinatorics 2026-04-28 v1 Discrete Mathematics

Abstract

We extend a recent construction concerning polychromatic colorings of hereditary hypergraph families. For every integer h4h\ge 4 we construct a (2h1)(2h-1)-uniform hypergraph which has no polychromatic 33-coloring, but all of whose hh-heavy restricted subhypergraphs are 22-colorable. Together with the previously known case h=3h=3, this gives examples with uniformity 2h12h-1 for every h3h\ge 3. The construction is based on complements of suitable hh-uniform hypergraphs on 3h13h-1 vertices. For h9h\ge 9 we prove existence by a simple probabilistic argument; the remaining cases 4h84\le h\le 8 are certified by a short exhaustive computer check, whose fully reproducible description and source code are included in the appendix.

Keywords

Cite

@article{arxiv.2604.24412,
  title  = {Note on polychromatic coloring of hereditary hypergraph families II},
  author = {Dömötör Pálvölgyi},
  journal= {arXiv preprint arXiv:2604.24412},
  year   = {2026}
}

Comments

This manuscript, including this disclaimer, was written by ChatGPT 5.5 Thinking, based on an interactive discussion with D\"om\"ot\"or P\'alv\"olgyi. The mathematical correctness of the manuscript has been verified by the author