Star 5-edge-colorings of subcubic multigraphs

Abstract

The star chromatic index of a multigraph $G$, denoted ${\chi }_s^{\prime }(G)$, is the minimum number of colors needed to properly color the edges of $G$ such that no path or cycle of length four is bi-colored. A multigraph $G$ is star $k$-edge-colorable if ${\chi }_s^{\prime }(G)\le k$. Dvořák, Mohar and Šámal [Star chromatic index, J Graph Theory 72 (2013), 313--326] proved that every subcubic multigraph is star $7$-edge-colorable, and conjectured that every subcubic multigraph should be star $6$-edge-colorable. Kerdjoudj, Kostochka and Raspaud considered the list version of this problem for simple graphs and proved that every subcubic graph with maximum average degree less than $7/3$ is star list-$5$-edge-colorable. It is known that a graph with maximum average degree $14/5$ is not necessarily star $5$-edge-colorable. In this paper, we prove that every subcubic multigraph with maximum average degree less than $12/5$ is star $5$-edge-colorable.

to appear in Discrete Mathematics. arXiv admin note: text overlap with arXiv:1701.04105

Cited by in corpus (2)

• On star edge colorings of bipartite and subcubic graphs
• Star Edge-Coloring of Square Grids