Characterizations of (4K1, C4, C5)-free graphs

Given a set L of graphs, a graph G is L -free if G does not contain any graph in L as an induced subgraph. There has been keen interest in colouring graphs whose forbidden list L contains graphs with four vertices. A recent paper of Lozin and Malyshev (in press) discusses the state of the art on this problem, identifying three outstanding classes: L = ( 4 K 1 , claw ) , L = ( 4 K 1 , claw, co-diamond ) , and L = ( 4 K 1 , C 4 ) . In this paper we investigate the class of ( 4 K 1 , C 4 , C 5 )-free graphs and show that if G is a ( 4 K 1 , C 4 , C 5 )-free graph, then G either has bounded clique width or is perfect.