Distance-Based Polynomials and Topological Indices for Hierarchical Hypercube Networks

Topological indices are the numbers associated with the graphs of chemical compounds/networks that help us to understand their properties. The aim of this paper is to compute topological indices for the hierarchical hypercube networks. We computed Hosoya polynomials, Harary polynomials, Wiener index, modified Wiener index, hyper-Wiener index, Harary index, generalized Harary index, and multiplicative Wiener index for hierarchical hypercube networks. Our results can help to understand topology of hierarchical hypercube networks and are useful to enhance the ability of these networks. Our results can also be used to solve integral equations.

Harary Index of Anthracene’s Chemical Graph Using Domination

Consider a Anthracene’s Chemical Graph as a connected finite simple graph. In such a chemical graph, vertices and edges signify atoms and bonds respectively. Harary Index is a distance based on the topological index. This paper obtains Harary Index of Chemical Graph of Anthracene using Reciprocal Minimum Dominating Distance Matrix.

BOUNDS ON HARARY INDEX WITH RESPECT TO VERTEX CONNECTIVITY, INDEPENDENT NUMBER AND INDEPENDENT DOMINATION NUMBER OF A GRAPH

In the present paper, we obtain bounds for Harary index $H(G)$ of a connected (molecular) graph in terms of vertex connectivity, independent number, independent domination number and characterize graphs extremal with respect to them.

Remarks on Distance Based Topological Indices for ℓ-Apex Trees

A graph G is called an ℓ-apex tree if there exist a vertex subset A ⊂ V ( G ) with cardinality ℓ such that G − A is a tree and there is no other subset of smaller cardinality with this property. In the paper, we investigate extremal values of several monotonic distance-based topological indices for this class of graphs, namely generalized Wiener index, and consequently for the Wiener index and the Harary index, and also for some newer indices as connective eccentricity index, generalized degree distance, and others. For the one extreme value we obtain that the extremal graph is a join of a tree and a clique. Regarding the other extreme value, which turns out to be a harder problem, we obtain results for ℓ = 1 and pose some open questions for higher ℓ. Symmetry has always played an important role in Graph Theory, in recent years, this role has increased significantly in several branches of this field, including topological indices of graphs.

Some Topological Invariants of Graphs Associated with the Group of Symmetries

A topological index is a quantity that is somehow calculated from a graph (molecular structure), which reflects relevant structural features of the underlying molecule. It is, in fact, a numerical value associated with the chemical constitution for the correlation of chemical structures with various physical properties, chemical reactivity, or biological activity. A large number of properties like physicochemical properties, thermodynamic properties, chemical activity, and biological activity can be determined with the help of various topological indices such as atom-bond connectivity indices, Randić index, and geometric arithmetic indices. In this paper, we investigate topological properties of two graphs (commuting and noncommuting) associated with an algebraic structure by determining their Randić index, geometric arithmetic indices, atomic bond connectivity indices, harmonic index, Wiener index, reciprocal complementary Wiener index, Schultz molecular topological index, and Harary index.

On extremal bipartite graphs with given number of cut edges

Let [Formula: see text] be a topological index of a graph. If [Formula: see text] (or [Formula: see text], respectively) for each edge [Formula: see text], then [Formula: see text] is monotonically decreasing (or increasing, respectively) with the addition of edges. In this paper, by a unified approach, we determine the extremal values of some monotonic topological indices, including the Wiener index, the hyper-Wiener index, the Harary index, the connective eccentricity index, the eccentricity distance sum, among all connected bipartite graphs with a given number of cut edges, and characterize the corresponding extremal graphs, respectively.