English

Lower bounds for Ramsey numbers of bounded degree hypergraphs

Combinatorics 2025-08-18 v3

Abstract

We prove that, for all k3,k \ge 3, and any integers Δ,n\Delta, n with nΔ,n \ge \Delta, there exists a kk-uniform hypergraph on nn vertices with maximum degree at most Δ\Delta whose 44-color Ramsey number is at least twk(ckΔ)n\mathrm{tw}_k(c_k \Delta) \cdot n, for some constant ck>0c_k > 0, where twk\mathrm{tw}_k denotes the tower function. For k4,k \ge 4, this is tight up to the constant ckc_k and for k=3k = 3 it is known to be tight up to a factor of logΔ\log \Delta on top of the tower. It extends a well-known result of Graham, R\"{o}dl and Ruci\'{n}ski for graphs and answers a question of Conlon, Fox and Sudakov from 2008.

Keywords

Cite

@article{arxiv.2502.20863,
  title  = {Lower bounds for Ramsey numbers of bounded degree hypergraphs},
  author = {Domagoj Bradač and Zach Hunter and Benny Sudakov},
  journal= {arXiv preprint arXiv:2502.20863},
  year   = {2025}
}

Comments

Improved result to a tight linear dependence on $\Delta$ on top of the tower

R2 v1 2026-06-28T22:01:31.469Z