摘要
Given a simple undirected graph G. We denote the sets of its vertices and edges by V（G） and E（G） respectively. G is called a （P, P—K） graph （or G=（P, P—K）） if |V（G）|=P and |E（G）|=|V（G）|—K. Let {G1, G2} be a pair of graphs of the same order. If G1 is isomorphic to a subgraph of （?）2, where （?）2 is the com-
