中国科学技术大学学报 ›› 2014, Vol. 44 ›› Issue (2): 96-100.DOI: 10.3969/j.issn.0253-2778.2014.02.003

• 原创论文 • 上一篇    下一篇

连通图的Harary指数上界及其极图

李小新   

  1. 1.池州学院数学系,安徽池州 247000;2.安庆师范学院数学与计算科学学院,安徽安庆 246133; 3.安徽大学数学科学学院,安徽合肥 230601
  • 收稿日期:2013-04-16 修回日期:2013-09-06 出版日期:2014-02-28 发布日期:2014-02-28
  • 通讯作者: 李小新
  • 作者简介:李小新(通讯作者),男,1976年生,硕士/副教授. 研究方向:代数图论与化学图论. E-mail:lxx@czu.edu.cn
  • 基金资助:
    国家自然科学基金 (11071002),安徽省教育厅自然科学研究重点项目(KJ2013A196)资助.

An upper bound for the Harary index of a connected graph and the corresponding extremal graph

LI Xiaoxin   

  1. 1.Department of Mathematics, Chizhou University, Chizhou 247000, China; 2.School of Mathematics and Computation Sciences, Anqing Normal University, Anqing 246133, China; 3.School of Mathematical Sciences, Anhui University, Hefei 230601, China
  • Received:2013-04-16 Revised:2013-09-06 Online:2014-02-28 Published:2014-02-28

摘要: 图的Harary指数定义为图的所有顶点对的距离的倒数之和.刻画了在给定点数和直径的图类中,Harary指数达到最大的极图,并由此确定了Harary指数关于直径的一个上界.另外,在n阶连通图中,刻画了Harary指数达到第二大和第三大的图的结构.

关键词: 图, Harary指数, 直径

Abstract: The Harary index of a graph is defined as the sum of reciprocals of distances between all pairs of vertices of the graph. The graph(s) with maximum Harary index among all graphs with given order and diameter was characterized, and an upper bound for the Harary index in terms of diameter was provided. In addition, the connected graphs of order n with the second maximum and the third maximum Harary indices were characterized, respectively.

Key words: graph, Harary index, diameter