Total coloring graphs with large maximum degree

Fuente: arXiv
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Auteurs principaux: Dalal, Aseem, McDonald, Jessica, Shan, Songling
Format: Preprint
Publié: 2024
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author Dalal, Aseem
McDonald, Jessica
Shan, Songling
author_facet Dalal, Aseem
McDonald, Jessica
Shan, Songling
contents We prove that for any graph $G$, the total chromatic number of $G$ is at most $Δ(G)+2\left\lceil \frac{|V(G)|}{Δ(G)+1} \right\rceil$. This saves one color in comparison with a result of Hind from 1992. In particular, our result says that if $Δ(G)\ge \frac{1}{2}|V(G)|$, then $G$ has a total coloring using at most $Δ(G)+4$ colors. When $G$ is regular and has a sufficient number of vertices, we can actually save an additional two colors. Specifically, we prove that for any $0<\varepsilon <1$, there exists $n_0\in \mathbb{N}$ such that: if $G$ is an $r$-regular graph on $n \ge n_0$ vertices with $r\ge \frac{1}{2}(1+\varepsilon) n$, then $χ_T(G) \le Δ(G)+2$. This confirms the Total Coloring Conjecture for such graphs $G$.
format Preprint
id arxiv_https___arxiv_org_abs_2405_07382
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Total coloring graphs with large maximum degree
Dalal, Aseem
McDonald, Jessica
Shan, Songling
Combinatorics
05C15
We prove that for any graph $G$, the total chromatic number of $G$ is at most $Δ(G)+2\left\lceil \frac{|V(G)|}{Δ(G)+1} \right\rceil$. This saves one color in comparison with a result of Hind from 1992. In particular, our result says that if $Δ(G)\ge \frac{1}{2}|V(G)|$, then $G$ has a total coloring using at most $Δ(G)+4$ colors. When $G$ is regular and has a sufficient number of vertices, we can actually save an additional two colors. Specifically, we prove that for any $0<\varepsilon <1$, there exists $n_0\in \mathbb{N}$ such that: if $G$ is an $r$-regular graph on $n \ge n_0$ vertices with $r\ge \frac{1}{2}(1+\varepsilon) n$, then $χ_T(G) \le Δ(G)+2$. This confirms the Total Coloring Conjecture for such graphs $G$.
title Total coloring graphs with large maximum degree
topic Combinatorics
05C15
url https://arxiv.org/abs/2405.07382