Homogeneous sets in hypergraphs with forbidden order-size pairs
Abstract
The well-known Erd\H{o}s-Hajnal conjecture states that for any graph , there exists such that every -vertex graph that contains no induced copy of has a homogeneous set of size at least . We consider a variant of the Erd\H{o}s-Hajnal problem for hypergraphs where we forbid a family of hypergraphs described by their orders and sizes. For graphs, we observe that if we forbid induced subgraphs on vertices and edges for any positive and , then we obtain large homogeneous sets. For triple systems, in the first nontrivial case , for every , we give bounds on the minimum size of a homogeneous set in a triple system where the number of edges spanned by every four vertices is not in . For all we determine if the growth rate is polylogarithmic. Several open problems remain.
Cite
@article{arxiv.2303.09578,
title = {Homogeneous sets in hypergraphs with forbidden order-size pairs},
author = {Maria Axenovich and Dhruv Mubayi and Lea Weber},
journal= {arXiv preprint arXiv:2303.09578},
year = {2023}
}