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

作者：Wu, Renfang; Tang, Zikai; Deng, Hanyuan^*

来源：Filomat, 2013, 27(1): 51-55.

DOI：10.2298/FIL1301051W

• Graph
• the harmonic index
• the minimum degree

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.

• 出版日期2013
• 单位湖南师范大学