Equitable and List Equitable Colorings of Graphs with Bounded Maximum Average Degree

Aijun Dong1, Qingsong Zou2, Guojun Li3
1 School of Science, Shandong Jiaotong University, Jinan, 250023, P. R. China
2Department of Mathematics, Xidian University, Xi’an, 710071, P. R. China
3School of Mathematics, Shandong University, Jinan, 250100, P. R. Cina

Abstract

A graph is said to be equitably \(k\)-colorable if the vertex set \(V(G)\) can be partitioned into \(k\) independent subsets \(V_1, V_2, \ldots, V_k\) such that \(||V_i| – |V_j|| \leq 1\) (\(1 \leq i, j \leq k\)). A graph \(G\) is equitably \(k\)-choosable if, for any given \(k\)-uniform list assignment \(L\), \(G\) is \(L\)-colorable and each color appears on at most \(\lceil \frac{|V(G)|}{k} \rceil\) vertices. In this paper, we prove that if \(G\) is a graph such that \(\mathrm{mad}(G) \leq 3\), then \(G\) is equitably \(k\)-colorable and equitably \(k\)-choosable where \(k \geq \max\{\Delta(G), 5\}\).