Bipartite-perfect graphs

Two graphs G and H with the same vertex set V are P-4-isomorphic if there exists a permutation pi on V such that, for all subsets S subset of or equal to V, S induces a chordless path on four vertices (denoted by P-4) in G if and only if pi(S) induces a P-4 in H. This paper gives a characterization of all graphs P-4-isomorphic to a bipartite graph, which we call bipartite-perfect graphs. The characterization is based on graphs P-4-isomorphic to a tree previously described by A. Brandstadt and the author, and implies a linear time recognition algorithm for bipartite-perfect graphs. (C) 2002 Elsevier Science B.V. All rights reserved.