English

A canonical Ramsey theorem for even cycles in random graphs

Combinatorics 2024-11-25 v1

Abstract

The celebrated canonical Ramsey theorem of Erd\H{o}s and Rado implies that for 2kN2\leq k\in \mathbb{N}, any colouring of the edges of KnK_n with nn sufficiently large gives a copy of C2kC_{2k} which has one of three canonical colour patterns: monochromatic, rainbow or lexicographic. In this paper we show that if p=ω(n1+1/(2k1)logn)p=\omega(n^{-1+1/(2k-1)}\log n), then G(n,p){\mathbf{G}}(n,p) will asymptotically almost surely also have the property that any colouring of its edges induces canonical copies of C2kC_{2k}. This determines the threshold for the canonical Ramsey property with respect to even cycles, up to a log\log factor.

Keywords

Cite

@article{arxiv.2411.14566,
  title  = {A canonical Ramsey theorem for even cycles in random graphs},
  author = {José D. Alvarado and Y. Kohayakawa and Patrick Morris and Guilherme O. Mota},
  journal= {arXiv preprint arXiv:2411.14566},
  year   = {2024}
}

Comments

24 pages + 4 pages of appendix, 1 figure

R2 v1 2026-06-28T20:08:26.114Z