English

3-uniform monotone paths and multicolor Ramsey numbers

Combinatorics 2024-11-26 v1

Abstract

The monotone path Pn+2P_{n+2} is an ordered 3-uniform hypergraph whose vertex set has size n+2n+2 and edge set consists of all consecutive triples. In this note, we consider the collection Jn\mathcal{J}_n of ordered 3-uniform hypergraphs named monotone paths with nn jumps, and we prove the following relation \begin{equation*} r(3;n) \leq R(P_{n+2},\mathcal{J}_n) \leq 4^n \cdot r(3;n), \end{equation*} where r(3;n)r(3;n) is the multicolor Ramsey number for triangles and R(Pn+2,Jn)R(P_{n+2},\mathcal{J}_n) is the hypergraph Ramsey number for Pn+2P_{n+2} versus any member of Jn\mathcal{J}_n. In particular, whether r(3;n)r(3;n) is exponential, which is a very old problem of Erd\H{o}s, is equivalent to whether R(Pn+2,Jn)R(P_{n+2},\mathcal{J}_n) is exponential.

Keywords

Cite

@article{arxiv.2411.15649,
  title  = {3-uniform monotone paths and multicolor Ramsey numbers},
  author = {Andrew Suk and Ji Zeng},
  journal= {arXiv preprint arXiv:2411.15649},
  year   = {2024}
}
R2 v1 2026-06-28T20:10:10.505Z