2021/09/28 by Ghanbari, Nima · 1 citation
#05C09 #05C12 #05C92 #Combinatorics (math.CO) #FOS: Mathematics
paper · doi:10.48550/arxiv.2109.13564
Let G=(V,E) be a finite simple graph. The Graovac-Ghorbani index of a graph G is defined as ABCGG(G)=∑uv∈ E(G)√((nu(uv,G)+nv(uv,G)-2)/(nu(uv,G)nv(uv,G))), where nu(uv,G) is the number of vertices closer to vertex u than vertex v of the edge uv∈ E(G). nv(uv,G) is defined analogously. The atom-bond connectivity index of a graph G is defined as ABC(G)=∑uv∈ E(G)√((du+dv-2)/(dudv)), where du is the degree of vertex u in G. Let G be a connected graph constructed from pairwise disjoint connected graphs G1,… ,Gk by selecting a vertex of G1, a vertex of G2, and identifying these two vertices. Then continue in this manner inductively. We say that G is obtained by point-attaching from G1, … ,Gk and that Gi's are the primary subgraphs of G. In this paper, we give some lower and upper bounds on Graovac-Ghorbani and atom-bond connectivity indices for these graphs. Additionally, we consider some particular cases of these graphs that are of importance in chemistry and study their Graovac-Ghorbani and atom-bond connectivity indices.