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Single-conflict colorings of degenerate graphs

Combinatorics 2026-03-16 v2 Discrete Mathematics

Abstract

We consider the single-conflict coloring problem, a graph coloring problem in which each edge of a graph receives a forbidden ordered color pair. The task is to find a vertex coloring such that no two adjacent vertices receive a pair of colors forbidden at an edge joining them. We show that for any assignment of forbidden color pairs to the edges of a dd-degenerate graph GG on nn vertices of edge-multiplicity at most loglogn\log \log n, O(dlogn)O(\sqrt{ d } \log n) colors are always enough to color the vertices of GG in a way that avoids every forbidden color pair. This answers a question of Dvo\v{r}\'ak, Esperet, Kang, and Ozeki for simple graphs (Journal of Graph Theory 2021).

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Cite

@article{arxiv.2112.06333,
  title  = {Single-conflict colorings of degenerate graphs},
  author = {Peter Bradshaw and Tomáš Masařík},
  journal= {arXiv preprint arXiv:2112.06333},
  year   = {2026}
}

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12 pages