English

Hypergraph anti-Ramsey theorems

Combinatorics 2024-10-15 v3

Abstract

The anti-Ramsey number ar(n,F)\mathrm{ar}(n,F) of an rr-graph FF is the minimum number of colors needed to color the complete nn-vertex rr-graph to ensure the existence of a rainbow copy of FF. We establish a removal-type result for the anti-Ramsey problem of FF when FF is the expansion of a hypergraph with a smaller uniformity. We present two applications of this result. First, we refine the general bound ar(n,F)=ex(n,F)+o(nr)\mathrm{ar}(n,F) = \mathrm{ex}(n,F_{-}) + o(n^r) proved by Erd{\H o}s--Simonovits--S{\' o}s, where FF_{-} denotes the family of rr-graphs obtained from FF by removing one edge. Second, we determine the exact value of ar(n,F)\mathrm{ar}(n,F) for large nn in cases where FF is the expansion of a specific class of graphs. This extends results of Erd{\H o}s--Simonovits--S{\' o}s on complete graphs to the realm of hypergraphs.

Keywords

Cite

@article{arxiv.2310.01186,
  title  = {Hypergraph anti-Ramsey theorems},
  author = {Xizhi Liu and Jialei Song},
  journal= {arXiv preprint arXiv:2310.01186},
  year   = {2024}
}

Comments

revised according to referee's suggestions

R2 v1 2026-06-28T12:38:16.560Z