摘要Let G be a graph and t a real number such that the implication k(G-S)】1 |S|≥t·k(G-S) holds for each set S of points of G. Then G will be said to be t-tough. Here k(G-S) is the number of components of G-S. Obviously, a 1-tough graph
3LI Jianping,TIAN Feng,SHEN Ruqun Institute of Systems Science,Academia Sinica,Beijing 100080,China Institute of Biophysics, Academia Sinica, Beijing 100101, China.A FURTHER GENERALIZATION OF JUNG'S THEOREM[J].Systems Science and Mathematical Sciences,1993,6(1):52-60.