engleski

On the sum-connectivity index

The sum-connectivity index of a simple graph G is defined in mathematical chemistry as R(+) (G) = Sigma(uv is an element of E(G)) (d(u) + d(v))(-1/2), where E(G) is the edge set of G and d(u) is the degree of vertex u in G. We give a best possible lower bound for the sum-connectivity index of a graph (a triangle-free graph, respectively) with n vertices and minimum degree at least two and characterize the extremal graphs, where n >= 11.

Sum-connectivity index ; Product-connectivity index ; Randie connectivity index ; Triangle-free graph ; Minimum degree

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