Acyclic vertex coloring of graphs of maximum degree 5

An acyclic vertex coloring of a graph is a proper vertex coloring such that there are no bichromatic cycles. The acyclic chromatic number of G, denoted a(G), is the minimum number of colors required for acyclic vertex coloring of graph G. For a family F of graphs, the acyclic chromatic number of F, denoted by a(F), is defined as the maximum a(G) over all the graphs G epsilon F. In this paper we show that a(F) = 8 where F is the family of graphs of maximum degree 5 and give a linear time algorithm to achieve this bound. (C) 2010 Elsevier B.V. All rights reserved.