On the harmonic index of quasi-tree graphs

作者：Lv, Jian-Bo^*

来源：Ars Combinatoria, 2018, 137: 305-315.

• harmonic index
• quasi-tree graphs
• tree

The harmonic index of a graph G is defined as the sum of weights 2/d(u)+d(v) over all edges uv of G, where d(u) and d(v) are the degrees of the vertices u and v in G, respectively. A graph G is called quasi tree, if there exists is an element of E V (G) such that G - u is a tree. In this paper, we give sharp lower hound on the harmonic index of quasi tree graphs.

• 出版日期2018-1
• 单位华中师范大学