English

Coloring distance graphs on the plane

Combinatorics 2022-01-13 v1

Abstract

We consider the coloring of certain distance graphs on the Euclidean plane. Namely, we ask for the minimal number of colors needed to color all points of the plane in such a way that pairs of points at distance in the interval [1,b][1,b] get different colors. The classic Hadwiger-Nelson problem is a special case of this question -- obtained by taking b=1b=1. The main results of the paper are improved lower and upper bounds on the number of colors for some values of bb. In particular, we determine the minimal number of colors for two ranges of values of bb - one of which is enlarging an interval presented by Exoo and the second is completely new. Up to our knowledge, these are the only known families of distance graphs on the plane with a determined nontrivial chromatic number. Moreover, we present the first 88-coloring for bb larger than values of bb for the known 77-colorings. As a byproduct, we give some bounds and exact values for bounded parts of the plane, specifically by coloring certain annuli.

Keywords

Cite

@article{arxiv.2201.04499,
  title  = {Coloring distance graphs on the plane},
  author = {Joanna Chybowska-Sokół and Konstanty Junosza-Szaniawski and Krzysztof Węsek},
  journal= {arXiv preprint arXiv:2201.04499},
  year   = {2022}
}
R2 v1 2026-06-24T08:47:46.859Z