A New Sufficient Condition For Hamiltonian Graphs
Hamilton图的一个新的充分条件

in this paper the following result is proved: If G is a 3-connected tough graph on n vertices with vertex connectivity K such that d(x) d(y) d(z) d(w) K for any independent set {x, y, x, w} of vertices x, y, z, w, then G is hamiltonian.