Let G = (V, E) be a simple connected graph with vertex set V(G) and edge set E(G) . The second GA and (Sz) indices a graph G are defined as 2 ( ) ( ) ( ) 2 ( ) ( ) ( ) e uv E G u v u v n e n e n e n e GA G , ( ) ( ) ( ) ( ) , e uv E G u v Sz G Sz n e n e where nu(e) is the number of vertices closer to u than v and nv(e) is the number of vertices closer to v than u. In this paper, some relations between the second GA index, (Sz)-1 and (Sz)-1/2 of G are studied.
