A Note on Acyclic Coloring of Strong Product of Graphs

A vertex coloring of a graph G is called acyclic if no two adjacent vertices have the same color and no cycle in G is bichromatic. The acyclic chromatic number a(G) of a graph G is the least number of colors in an acyclic coloring of G. In this paper, we obtain bound for the acyclic chromatic number of the strong product of a tree and a graph. An exact value for the acyclic chromatic number of the strong product of two trees is derived. Further observations are made on the upper bound for the strong product of three paths.