English

Set-coloring Ramsey numbers via codes

Combinatorics 2022-06-24 v1

Abstract

For positive integers n,r,sn,r,s with r>sr > s, the set-coloring Ramsey number R(n;r,s)R(n;r,s) is the minimum NN such that if every edge of the complete graph KNK_N receives a set of ss colors from a palette of rr colors, then there is guaranteed to be a monochromatic clique on nn vertices, that is, a subset of nn vertices where all of the edges between them receive a common color. In particular, the case s=1s=1 corresponds to the classical multicolor Ramsey number. We prove general upper and lower bounds on R(n;r,s)R(n;r,s) which imply that R(n;r,s)=2Θ(nr)R(n;r,s) = 2^{\Theta(nr)} if s/rs/r is bounded away from 00 and 11. The upper bound extends an old result of Erd\H{o}s and Szemer\'edi, who treated the case s=r1s = r-1, while the lower bound exploits a connection to error-correcting codes. We also study the analogous problem for hypergraphs.

Keywords

Cite

@article{arxiv.2206.11371,
  title  = {Set-coloring Ramsey numbers via codes},
  author = {David Conlon and Jacob Fox and Xiaoyu He and Dhruv Mubayi and Andrew Suk and Jacques Verstraete},
  journal= {arXiv preprint arXiv:2206.11371},
  year   = {2022}
}

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11 pages