A chain probe graph is a graph that admits an independent set S of vertices and a set F of pairs of elements of S such that G + F is a chain graph (i.e., a 2K2-free bipartite graph). We show that chain probe graphs are exactly the bipartite graphs that do not contain as an induced subgraph a member of a family of six forbidden subgraphs, and deduce an O(n2) recognition algorithm. Given a class C of graphs, a graph G = (V ,E) is said to be a C probe graph if there exists an independent set of… CONTINUE READING