Croatica Chemica Acta, Vol. 80 No. 2, 2007.
Original scientific paper
Comparing the Zagreb Indices
Pierre Hansen
Damir Vukičević
Abstract
Let G = (V, E) be a simple graph with n = |V | vertices and m = |E | edges; let d1, d2, …, dn denote the degrees of the vertices of G. If Δ= maxdi ≤ 4, G is a chemical graph. The first and second Zagreb indices are defined as
M1 = Σdi ²and M2 = Σd i d j
We show that for all chemical graphs M 1/n ≤ M2/m. This does not hold for all general graphs, connected or not.
Keywords
extremal graph; Zagreb index; AGX; chemical graphs
Hrčak ID:
12846
URI
Publication date:
12.6.2007.
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