设G是一个简单图,图G的Wiener指数是G中所有顶点的距离之和。本文刻画了给定顶点数和悬挂点数的图类中,Wiener指数取到最小、次小、第三小的极图,并由此确定了关于悬挂点数的Wiener指数的下界。
Let be a simple graph, the Wiener index of is the sum of distances between all pairs of vertices of. In this paper, we characterize the extremal graph with the first, the second and the third smallest Wiener index among all graphs with given order and the number of suspension points, and give the lower bounds of the Wiener index of graphs with given number of suspension point.