English

Triangle Ramsey numbers of complete graphs

Combinatorics 2025-10-13 v2

Abstract

A graph is HH-Ramsey if every two-coloring of its edges contains a monochromatic copy of HH. Define the FF-Ramsey number of HH, denoted by rF(H)r_F(H), to be the minimum number of copies of FF in a graph which is HH-Ramsey. This generalizes the Ramsey number and size Ramsey number of a graph. Addressing a question of Spiro, we prove that rK3(Kt)=(r(Kt)3)r_{K_3}(K_t)=\binom{r(K_t)}{3} for all sufficiently large tt. We do so through a result on graph coloring: there exists an absolute constant KK such that every rr-chromatic graph where every edge is contained in at least KK triangles must contain at least (r3)\binom{r}{3} triangles in total.

Keywords

Cite

@article{arxiv.2312.06895,
  title  = {Triangle Ramsey numbers of complete graphs},
  author = {Jacob Fox and Jonathan Tidor and Shengtong Zhang},
  journal= {arXiv preprint arXiv:2312.06895},
  year   = {2025}
}

Comments

14 pages

R2 v1 2026-06-28T13:47:51.421Z