English

Ramsey numbers for regular induced subgraphs

Combinatorics 2026-05-12 v2

Abstract

A problem proposed by Erd\H{o}s, Fajtlowicz and Staton asks for the smallest nn for which every graph on nn vertices contains a regular induced subgraph of order at least kk. A variation is to ask for a regular induced subgraph of order exactly kk. In this paper we provide exact values for k5k\le 5 and lower bounds for k=6k=6 and k=7k=7. We also improve the general lower bound of Alon, Krivelevich and Sudakov [SIAM J. Disc. Math, 2008].

Keywords

Cite

@article{arxiv.2604.08215,
  title  = {Ramsey numbers for regular induced subgraphs},
  author = {Paul W. Dyson and Brendan D. McKay},
  journal= {arXiv preprint arXiv:2604.08215},
  year   = {2026}
}

Comments

Improved bound on $N_7$

R2 v1 2026-07-01T12:01:07.781Z