On acyclic b-chromatic number of cubic graphs

TL;DR

This paper investigates the acyclic b-chromatic number of cubic graphs, exploring the maximum number of colors in such colorings where no further acyclic recoloring steps are possible.

Contribution

It introduces the concept of acyclic b-chromatic number for cubic graphs and analyzes its properties and bounds within this class of graphs.

Findings

Determines bounds for $A_b(G)$ in cubic graphs.

Identifies conditions under which $A_b(G)$ reaches certain values.

Provides new insights into acyclic colorings and recoloring processes.

Abstract

Let $G$ be a graph. An acyclic $k$-coloring of $G$ is a map $c:V(G)\rightarrow \{1,\dots,k\}$ such that $c(u)\neq c(v)$ for any $uv\in E(G)$ and the subgraph induced by the vertices of any two colors $i,j\in \{1,\dots,k\}$ is a forest. If every vertex $v$ of a color class $V_i$ misses a color $\ell_v\in\{1,\dots,k\}$ in its closed neighborhood, then every $v\in V_i$ can be recolored with $\ell_v$ and we obtain a $(k-1)$-coloring of $G$. If a new coloring $c'$ is also acyclic, then such a recoloring is an acyclic recoloring step and $c'$ is in relation $\triangleleft_a$ with $c$. The acyclic b-chromatic number $A_b(G)$ of $G$ is the maximum number of colors in an acyclic coloring where no acyclic recoloring step is possible. Equivalently, it is the maximum number of colors in a minimum element of the transitive closure of $\triangleleft_a$. In this paper, we consider $A_b(G)$ of cubic graphs.