A lower bound for the harmonic index of a graph with minimum degree at least two

被引：62

作者：

Wu, Renfang ^{[1
]}

Tang, Zikai ^{[1
]}

Deng, Hanyuan ^{[1
]}

机构：

[1] Hunan Normal Univ, Minist Educ China, Coll Math & Comp Sci, Key Lab High Performance Comp & Stochast Informat, Changsha 410081, Hunan, Peoples R China

来源：

FILOMAT | 2013年 / 27卷 / 01期

关键词：

Graph; the harmonic index; the minimum degree;

D O I：

10.2298/FIL1301051W

中图分类号：

O29 [应用数学];

学科分类号：

070104 ;

摘要：

The harmonic index H(G) of a graph G is defined as the sum of the weights 2/ d(u)+ d(v) of all edges uv of G, where d(u) denotes the degree of a vertex u in G. We give a best possible lower bound for the harmonic index of a graph (a triangle-free graph, respectively) with minimum degree at least two and characterize the extremal graphs.

引用

页码：51 / 55

页数：5

共 11 条

[1] Variable neighborhood search for extremal graphs: 1 The AutoGraphiX system [J].