Abstract :
The harmonic index of a graph G is dened as the sum of the weights 2
degG(u)+degG(v) of
all edges uv of G, where degG(u) denotes the degree of a vertex u in G. In this paper, we study the
harmonic index of subdivision graphs, t-subdivision graphs and also, S-sum and St-sum of graphs.
Keywords :
Zagreb index , inverse degree , S-sum , subdivision , Harmonic index
