Off-diagonal ordered Ramsey numbers of matchings
Abstract
For ordered graphs and , the ordered Ramsey number is the smallest such that every red/blue edge coloring of the complete graph on vertices contains either a blue copy of or a red copy of , where the embedding must preserve the relative order of vertices. One number of interest, first studied by Conlon, Fox, Lee, and Sudakov, is the "off-diagonal" ordered Ramsey number , where is an ordered matching on vertices. In particular, Conlon et al. asked what asymptotic bounds (in ) can be obtained for , where the maximum is over all ordered matchings on vertices. The best-known upper bound is , whereas the best-known lower bound is , and Conlon et al. hypothesize that for every ordered matching . We resolve two special cases of this conjecture. We show that the off-diagonal ordered Ramsey numbers for matchings in which edges do not cross are nearly linear. We also prove a truly sub-quadratic upper bound for random matchings with interval chromatic number .
Keywords
Cite
@article{arxiv.1808.04025,
title = {Off-diagonal ordered Ramsey numbers of matchings},
author = {Dhruv Rohatgi},
journal= {arXiv preprint arXiv:1808.04025},
year = {2018}
}
Comments
15 pages, 3 figures