Improved bounds on the difference between the Szeged index and the Wiener index of graphs

  • Authors:
  • Sandi Klavar;M. J. Nadjafi-Arani

  • Affiliations:
  • -;-

  • Venue:
  • European Journal of Combinatorics
  • Year:
  • 2014

Quantified Score

Hi-index 0.00

Visualization

Abstract

Let W(G) and Sz(G) be the Wiener index and the Szeged index of a connected graph G, respectively. It is proved that if G is a connected bipartite graph of order n=4, size m=n, and if @? is the length of a longest isometric cycle of G, then Sz(G)-W(G)=n(m-n+@?-2)+(@?/2)^3-@?^2+2@?. It is also proved if G is a connected graph of order n=5 and girth g=5, then Sz(G)-W(G)=PI"v(G)-n(n-1)+(n-g)(g-3)+P(g), where PI"v(G) is the vertex PI index of G and P is a cubic polynomial. These theorems extend related results from Chen et al. (2014). Several lower bounds on the difference Sz(G)-W(G) for general graphs G are also given without any condition on the girth.