English

High girth hypergraphs with unavoidable monochromatic or rainbow edges

Combinatorics 2016-08-18 v2

Abstract

A classical result of Erd\H{o}s and Hajnal claims that for any integers k,r,g2k, r, g \geq 2 there is an rr-uniform hypergraph of girth at least gg with chromatic number at least kk. This implies that there are sparse hypergraphs such that in any coloring of their vertices with at most k1k-1 colors there is a monochromatic hyperedge. We show that for any integers r,g2r, g\geq 2 there is an rr-uniform hypergraph of girth at least gg such that in any coloring of its vertices there is either a monochromatic or a rainbow (totally multicolored) edge. We give a probabilistic and a deterministic proof of this result.

Keywords

Cite

@article{arxiv.1607.06600,
  title  = {High girth hypergraphs with unavoidable monochromatic or rainbow edges},
  author = {Maria Axenovich and Annette Karrer},
  journal= {arXiv preprint arXiv:1607.06600},
  year   = {2016}
}

Comments

Corrected remark to references. The paper [8] addresses both graphs and hypergraphs

R2 v1 2026-06-22T15:01:27.137Z