English

Ramsey lower bounds for bounded degree hypergraphs

Combinatorics 2026-03-27 v1

Abstract

We prove that for all k3k \ge 3 and any integers Δ,n\Delta, n with n2Δ,n \ge 2^\Delta, there exists a kk-graph on nn vertices with maximum degree at most Δ\Delta such that r(H)\twk1(ckΔ)nr(H)\geq\tw_{k-1}(c_k \Delta) \cdot n for some constant ck>0c_k > 0, where \twk\tw_k denotes the tower function. This makes the first progress toward a problem proposed by Conlon, Fox, and Sudakov (2009), who asked whether r(H)\twk(ckΔ)nr(H)\geq\tw_{k}(c_k \Delta) \cdot n holds. Our proof relies on a novel construction of a kk-graph on a growing number of vertices nn while keeping the maximum degree bounded by a fixed Δ\Delta.

Keywords

Cite

@article{arxiv.2603.24627,
  title  = {Ramsey lower bounds for bounded degree hypergraphs},
  author = {Chunchao Fan and Qizhong Lin},
  journal= {arXiv preprint arXiv:2603.24627},
  year   = {2026}
}

Comments

11 pages

R2 v1 2026-07-01T11:37:49.858Z