English

Counting multiple graphs in generalized Tur\'an problems

Combinatorics 2024-01-17 v2

Abstract

We are given graphs H1,,HkH_1,\dots,H_k and FF. Consider an FF-free graph GG on nn vertices. What is the largest sum of the number of copies of HiH_i? The case k=1k=1 has attracted a lot of attention. We also consider a colored variant, where the edges of GG are colored with kk colors. What is the largest sum of the number of copies of HiH_i in color ii? Our motivation to study this colored variant is a recent result stating that the Tur\'an number of the rr-uniform Berge-FF hypergraphs is at most the quantity defined above for k=2k=2, H1=KrH_1=K_r and H2=K2H_2=K_2. In addition to studying these new questions, we obtain new results for generalized Tur\'an problems and also for Berge hypergraphs.

Keywords

Cite

@article{arxiv.2007.11645,
  title  = {Counting multiple graphs in generalized Tur\'an problems},
  author = {Dániel Gerbner},
  journal= {arXiv preprint arXiv:2007.11645},
  year   = {2024}
}

Comments

23 pages

R2 v1 2026-06-23T17:19:40.510Z