On 2n+L-Vertex-Free Graphs

Abstract

We shall introduce the concepts of pseudoadjacent, pseudocoatraction and pseudoho-momorphism. We shall show, with the help of these concepts, in theorem 2 that every quadrilateral graph V (which is a 4-vertexgraph) has chromatic number 2. From this theorem follows our main result in theorem 4 that every 2n+l-vertex free graph has chromatic number 2.