On The Properties Of R_max Index Of A Graph

Let G=(V, E) be a simple connected graph with vertex set V and edge set E. The Rmax index of G is defined as where d(u) denotes the degree of a vertex u in G.In this paper, we first give a best possible lower bound of Rmax for a graph in terms of the minimum degree, and characterize the corresponding extremal graph; Then, we discuss the relations between Rmax index and the girth, the chromatic number, average eccentricity and the adjacency spectral radius of a graph.