Monochromatic connectivity and graph products

Abstract

The concept of monochromatic connectivity was introduced by Caro and Yuster. A path in an edge-colored graph is called a monochromatic path if all the edges on the path are colored the same. An edge-coloring of [Formula: see text] is a monochromatic connection coloring ([Formula: see text]-coloring, for short) if there is a monochromatic path joining any two vertices in [Formula: see text]. The monochromatic connection number, denoted by [Formula: see text], is defined to be the maximum number of colors used in an [Formula: see text]-coloring of a graph [Formula: see text]. In this paper, we study the monochromatic connection number on the lexicographical, strong, Cartesian and direct products and present several upper and lower bounds for these products of graphs.