On the Hosoya Index of Unicyclic Graphs with a Given Diameter

Shuchao Li1, Zhongxun, Zhu2
1Faculty of Mathematics and Statistics, Central China Normal University, Wuhan 430079, P.R. China
2Department of Computer Science, South Central University for Nationalities, Wuhan 430074, P.R. China

Abstract

The Hosoya index of a graph is defined as the total number of the matchings of the graph. In this paper, we determine the lower bounds for the Hosoya index of unicyclic graph with a given diameter. The corresponding extrenal graphs are characterized.