Strong edge colorings of graphs and the covers of Kneser graphs

Autor: Lužar, Borut, Mačajová, Edita, Škoviera, Martin, Soták, Roman
Rok vydání: 2021
Předmět:
Druh dokumentu: Working Paper
DOI: 10.1002/jgt.22802
Popis: A proper edge coloring of a graph is strong if it creates no bichromatic path of length three. It is well known that for a strong edge coloring of a $k$-regular graph at least $2k-1$ colors are needed. We show that a $k$-regular graph admits a strong edge coloring with $2k-1$ colors if and only if it covers the Kneser graph $K(2k-1,k-1)$. In particular, a cubic graph is strongly $5$-edge-colorable whenever it covers the Petersen graph. One of the implications of this result is that a conjecture about strong edge colorings of subcubic graphs proposed by Faudree et al. [Ars Combin. 29 B (1990), 205--211] is false.
Databáze: arXiv