The general connectivity indices of catacondensed hexagonal systems

Abstract

The general connectivity index Rα(G) of a graph G is defined as ∑(u,v)(dudv), where uv is an edge of G, α ∈ ℝ and α ≠ 0. In this paper, a formula is given for computing the general connectivity indices Rα of catacondensed hexagonal systems. We show that the general connectivity index Rα is monotone decreasing over the number of inlets in the system. The catacondensed hexagonal systems with the first up to the third extremal general connectivity indices are completely characterized. © 2009 Springer Science+Business Media, LLC.