English

Sparse halves in $K_4$-free graphs

Combinatorics 2020-07-30 v1

Abstract

A conjecture of Chung and Graham states that every K4K_4-free graph on nn vertices contains a vertex set of size n/2\lfloor n/2 \rfloor that spans at most n2/18n^2/18 edges. We make the first step toward this conjecture by showing that it holds for all regular graphs.

Keywords

Cite

@article{arxiv.2007.14623,
  title  = {Sparse halves in $K_4$-free graphs},
  author = {Xizhi Liu and Jie Ma},
  journal= {arXiv preprint arXiv:2007.14623},
  year   = {2020}
}

Comments

19 pages including 3 pages appendix

R2 v1 2026-06-23T17:29:05.228Z