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arXiv · 2210.04649

Locally irregular edge-coloring of subcubic graphs

Borut Lužar·Mária Maceková·Simona Rindošová·Roman Soták·Katarína Sroková·Kenny Štorgel
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Abstract

A graph is {\em locally irregular} if no two adjacent vertices have the same degree. A {\em locally irregular edge-coloring} of a graph $G$ is such an (improper) edge-coloring that the edges of any fixed color induce a locally irregular graph. Among the graphs admitting a locally irregular edge-coloring, i.e., {\em decomposable graphs}, only one is known to require $4$ colors, while for all the others it is believed that $3$ colors suffice. In this paper, we prove that decomposable claw-free graphs with maximum degree $3$, all cycle permutation graphs, and all generalized Petersen graphs admit a locally irregular edge-coloring with at most $3$ colors. We also discuss when $2$ colors suffice for a locally irregular edge-coloring of cubic graphs and present an infinite family of cubic graphs of girth $4$ which require $3$ colors.

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Borut Lužar, Mária Maceková, Simona Rindošová, Roman Soták, Katarína Sroková, Kenny Štorgel. 2022-10-10. Locally irregular edge-coloring of subcubic graphs. https://doi.org/10.1016/j.dam.2023.06.020

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