几类联图的顶点PI指数

Vertex PI Index of Several Kinds of Join Graphs

PI指数是从Wiener指数繁衍出来的一类拓扑指数,它不仅是图理论中很重要的图参数,而且在现代化学图论中用来刻画分子图结构,同时对相应结构图反映出其特征和性质具有重大意义。本文用分类讨论法计算出了几类联图P_(n)∨K_(m)^(-),C_(n)∨K_(m)^(-),K_(n)∨K_(m)^(-),F_(1·n)∨K_(m)^(-)的顶点PI指数的精确值。

PI index is a kind of topological index derived from Wiener index.It is not only a very important graph parameter in graph theory,but also used to describe the structure of molecular graphs in modern chemical graph theory,and it is of great significance to reflect the characteristics and properties of the corresponding structure graph.In this paper,we calculated the precise value of vertex PI index of several types of joint graphs such as P_(n)∨K_(m)^(-),C_(n)∨K_(m)^(-),K_(n)∨K_(m)^(-),F_(1·n)∨K_(m)^(-) by use classification discussion method.