English

t-wise Berge and t-heavy hypergraphs

Combinatorics 2019-12-10 v2

Abstract

In many proofs concerning extremal parameters of Berge hypergraphs one starts with analyzing that part of that shadow graph which is contained in many hyperedges. Capturing this phenomenon we introduce two new types of hypergraphs. A hypergraph H\mathcal{H} is a tt-heavy copy of a graph FF if there is a copy of FF on its vertex set such that each edge of FF is contained in at least tt hyperedges of H\mathcal{H}. H\mathcal{H} is a tt-wise Berge copy of FF if additionally for distinct edges of FF those tt hyperedges are distinct. We extend known upper bounds on the Tur\'an number of Berge hypergraphs to the tt-wise Berge hypergraphs case. We asymptotically determine the Tur\'an number of tt-heavy and tt-wise Berge copies of long paths and cycles and exactly determine the Tur\'an number of tt-heavy and tt-wise Berge copies of cliques. In the case of 3-uniform hypergraphs, we consider the problem in more details and obtain additional results.

Keywords

Cite

@article{arxiv.1902.03213,
  title  = {t-wise Berge and t-heavy hypergraphs},
  author = {Dániel Gerbner and Dániel T. Nagy and Balázs Patkós and Máté Vizer},
  journal= {arXiv preprint arXiv:1902.03213},
  year   = {2019}
}

Comments

20 pages

R2 v1 2026-06-23T07:36:00.833Z