Off-diagonal hypergraph Ramsey numbers
Abstract
The Ramsey number is the minimum such that every red-blue coloring of the -subsets of contains a red set of size or a blue set of size , where a set is red (blue) if all of its -subsets are red (blue). A -uniform \emph{tight path} of size , denoted by , is a set of vertices in , and all edges of the form . Let be the minimum such that every red-blue coloring of the -subsets of results in a red or a blue set of size . The problem of estimating both and for goes back to the seminal work of Erdos and Szekeres from 1935, while the case was first investigated by Erdos and Rado in 1952. In this paper, we deduce a quantitative relationship between multicolor variants of and . This yields several consequences including the following: (1) We determine the correct tower growth rate for both and for . The question of determining the tower growth rate of for all was posed by Erdos and Hajnal in 1972. (2) We show that determining the tower growth rate of is equivalent to determining the tower growth rate of , which is a notorious conjecture of Erdos, Hajnal and Rado from 1965 that remains open. Some related off-diagonal hypergraph Ramsey problems are also explored.
Cite
@article{arxiv.1505.05767,
title = {Off-diagonal hypergraph Ramsey numbers},
author = {Dhruv Mubayi and Andrew Suk},
journal= {arXiv preprint arXiv:1505.05767},
year = {2015}
}