English

Total coloring graphs with large maximum degree

Combinatorics 2024-05-14 v1

Abstract

We prove that for any graph GG, the total chromatic number of GG is at most Δ(G)+2V(G)Δ(G)+1\Delta(G)+2\left\lceil \frac{|V(G)|}{\Delta(G)+1} \right\rceil. This saves one color in comparison with a result of Hind from 1992. In particular, our result says that if Δ(G)12V(G)\Delta(G)\ge \frac{1}{2}|V(G)|, then GG has a total coloring using at most Δ(G)+4\Delta(G)+4 colors. When GG is regular and has a sufficient number of vertices, we can actually save an additional two colors. Specifically, we prove that for any 0<ε<10<\varepsilon <1, there exists n0Nn_0\in \mathbb{N} such that: if GG is an rr-regular graph on nn0n \ge n_0 vertices with r12(1+ε)nr\ge \frac{1}{2}(1+\varepsilon) n, then χT(G)Δ(G)+2\chi_T(G) \le \Delta(G)+2. This confirms the Total Coloring Conjecture for such graphs GG.

Keywords

Cite

@article{arxiv.2405.07382,
  title  = {Total coloring graphs with large maximum degree},
  author = {Aseem Dalal and Jessica McDonald and Songling Shan},
  journal= {arXiv preprint arXiv:2405.07382},
  year   = {2024}
}
R2 v1 2026-06-28T16:24:45.843Z