On the $δ$-chromatic numbers of the Cartesian products of graphs

Wipawee Tangjai, Witsarut Pho-on, Panupong Vichitkunakorn

Published 2024-01-01Version 1

In this work, we study the $\delta$-chromatic number of a graph which is the chromatic number of the $\delta$-complement of a graph. We give a structure of the $\delta$-complements and sharp bounds on the $\delta$-chromatic numbers of the Cartesian products of graphs. Furthermore, we compute the $\delta$-chromatic numbers of various classes of Cartesian product graphs, including the Cartesian products between cycles, paths, and stars.