Note on inverse sum indeg index of graphs

Abstract

The inverse sum indeg index of a connected graph G is defined as the sum of the ratio for all edges uv in the edge set of G, where denotes the degree of a point u. Recently, Pattabiraman [] has obtained bounds for the inverse sum indeg index of graphs. The upper and lower bounds obtained in terms of harmonic index and second Zagreb index are prone to some error. In this note we correct these errors by establishing the proper bounds in terms of harmonic index and second Zagreb index.

Keywords

• degree of a point
• inverse sum indeg index
• harmonic index
• zagreb index