In a study on the structure–dependency of the total π-electron energy from 1972, Trinajstić and one of the present authors have shown that it depends on the sums ∑ v∈V d(v) 2 and ∑ v∈V d(v) , where d(v) is the degree of a vertex v of the underling molecular graph G. The first sum was later named first Zagreb index and over the years became one of the most investigated graph–based molecular stru...

The m-order connectivity index mχ(G) of a molecular graph G is the sum of the weights (di1di2 · · · dim+1) 1 2 , where di1di2 · · · dim+1 runs over all paths of length m in G and di denotes the degree of vertex vi. Dendrimer is a polimer molecule with a distinctive structure that resembles the crown of a tree. In this paper we compute second-order and third-order connectivity indices of an infi...

A multivariate quantitative data is often summarized into a general index as a weighted sum when each variate has a prescribed order. Although the sum of standardized scores is a sensible choice of index, it may have negative correlation with some of the variates. In this paper, a general index that has positive correlation with all the variates is constructed. The index is applied to study the...

Phenol formaldehyde (phenolic resin) has a wide range of moldings. However, it immense consumption in manufacturing electrical equipment due to its insulating property. Phenolic resin retains properties at the freezing point, and also age cannot be determined. Due insulator property, use equipment. In this article, degree-based topological indices phenol are determined with help M-polynomial. W...

The present note is devoted to establish some extremal results for the zerothorder general Randić index of cacti, characterize the extremal polyomino chains with respect to the aforementioned index, and hence to generalize two already reported results.

Let T ∆ n denote the set of trees of order n, in which the degree of each vertex is bounded by some integer ∆. Suppose that every tree in T ∆ n is equally likely. We show that the number of vertices of degree j in T ∆ n is asymptotically normal with mean (μj + o(1))n and variance (σj + o(1))n, where μj , σj are some constants. As a consequence, we give estimate to the value of the general Zagre...

The general Randić index Rα(G) is the sum of the weight d(u)d(v)α over all edges uv of a graph G, where α is a real number and d(u) is the degree of the vertex u of G. In this paper, for any real number α = 0, the first three minimum general Randić indices among trees are determined, and the corresponding extremal trees are characterized.