English

Coloring directed hypergraphs

Combinatorics 2022-05-24 v1

Abstract

Inspired by earlier results about proper and polychromatic coloring of hypergraphs, we investigate such colorings of directed hypergraphs, that is, hypergraphs in which the vertices of each hyperedge is partitioned into two parts, a tail and a head. We present a conjecture of D. P\'alv\"olgyi and the author, which states that directed hypergraphs with a certain restriction on their pairwise intersections can be colored with two colors. Besides other contributions, our main result is a proof of this conjecture for 33-uniform directed hypergraphs. This result can be phrased equivalently such that if a 33-uniform directed hypergraph avoids a certain directed hypergraph with two hyperedges, then it admits a proper 22-coloring. Previously, only extremal problems regarding the maximum number of edges of directed hypergraphs that avoid a certain hyperedge were studied.

Keywords

Cite

@article{arxiv.2205.11271,
  title  = {Coloring directed hypergraphs},
  author = {Balázs Keszegh},
  journal= {arXiv preprint arXiv:2205.11271},
  year   = {2022}
}