Brooks' theorem with forbidden colors
Combinatorics
2023-03-14 v1
Abstract
We consider extensions of Brooks' classic theorem on vertex coloring where some colors cannot be used on certain vertices. In particular we prove that if is a connected graph with maximum degree that is not a complete graph and is a set of vertices where either (i) at most colors are forbidden for every vertex in , and any two vertices of are at distance at least , or (ii) at most colors are forbidden for every vertex in , and any two vertices of are at distance at least , then there is a proper -coloring of respecting these constraints. In fact, we shall prove that these results hold in the more general setting of list colorings. These results are sharp.
Cite
@article{arxiv.2303.06917,
title = {Brooks' theorem with forbidden colors},
author = {Carl Johan Casselgren},
journal= {arXiv preprint arXiv:2303.06917},
year = {2023}
}