THE MINIMUM HARMONIC INDEX FOR UNICYCLIC GRAPHS WITH GIVEN DIAMETER

被引:7
|
作者
Zhong, Lingping [1 ]
机构
[1] Nanjing Univ Aeronaut & Astronaut, Dept Math, Nanjing 210016, Jiangsu, Peoples R China
基金
中国国家自然科学基金;
关键词
harmonic index; unicyclic graphs; diameter; TOPOLOGICAL INDEXES; RANDIC-INDEX; FIXED DIAMETER; CONJECTURES; EIGENVALUE; NUMBER;
D O I
10.7151/dmgt.2007
中图分类号
O1 [数学];
学科分类号
0701 ; 070101 ;
摘要
The harmonic index 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. In this paper, we present the minimum harmonic index for unicyclic graphs with given diameter and characterize the corresponding extremal graphs. This answers an unsolved problem of Zhu and Chang [26]. Keywords: harmonic index, unicyclic graphs, diameter.
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页码:429 / 442
页数:14
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