文献类型：期刊文献

英文题名：On The Harmonic Index and The Minimum Degree of A Graph

作者：Chang, Renying[1];Zhu, Yan[2]

机构：[1]Linyi Univ, Dept Math, Linyi 276005, Shandong, Peoples R China;[2]E China Univ Sci & Technol, Dept Math, Shanghai 200237, Peoples R China

年份：2012

卷号：15

期号：4

起止页码：335

外文期刊名：ROMANIAN JOURNAL OF INFORMATION SCIENCE AND TECHNOLOGY

收录：;WOS:【SCI-EXPANDED(收录号:WOS:000323706200003)】；

基金：This work is supported by AMEP of Linyi University. This work is supported by NSFC(No. 11226288 and No. 11301251), the Fundamental Research Funds for the Central Universities

语种：英文

外文关键词：Harmonic index; triangle-free graph; minimum degree

摘要：The harmonic index H(G) of a graph G is the sum of 2/ d(u)+d(v)over all edges uv of G, where d(u) denotes the degree of a vertex u in G. In this paper, we give the minimum value of H(G) for graphs G with given minimum degree delta(G) >= 2 and characterize the corresponding extremal graph. Furthermore, we prove a best-possible lower bound on the harmonic index of a triangle-free graph G with arbitrary minimum degree delta(G).