Comparison Between Two Kinds of Connectivity Indices for Measuring the π-Electronic Energies of Benzenoid Hydrocarbons

2019 ◽  
Vol 74 (5) ◽  
pp. 367-370 ◽  
Author(s):  
Deqiang Chen
Keyword(s):  
Real Number ◽  
Molecular Descriptors ◽  
Connectivity Index ◽  
Benzenoid Hydrocarbons ◽  
The Real ◽  
Connectivity Indices ◽  
General Product

AbstractIn this paper, we show that both the general product-connectivity index χα and the general sum-connectivity index \({}^{s}{\chi_{\alpha}}\) are closely related molecular descriptors when the real number α is in some interval. By comparing these two kinds of indices, we show that the sum-connectivity index \({}^{s}{\chi_{-0.5601}}\) is the best one for measuring the π-electronic energies of lower benzenoid hydrocarbons. These improve the earlier results.

scholarly journals Some Eccentricity-Based Topological Indices and Polynomials of Poly(EThyleneAmidoAmine) (PETAA) Dendrimers

Processes ◽  
2019 ◽  
Vol 7 (7) ◽  
pp. 433 ◽  
Author(s):  
Jialin Zheng ◽  
Zahid Iqbal ◽  
Asfand Fahad ◽  
Asim Zafar ◽  
Adnan Aslam ◽  
...  
Keyword(s):  
Molecular Descriptors ◽  
Molecular Graph ◽  
Topological Indices ◽  
Molecular Structures ◽  
Connectivity Index ◽  
Connectivity Indices ◽  
Numerical Invariants ◽  
Explicit Representations ◽  
Pharmaceutical Properties

Topological indices have been computed for various molecular structures over many years. These are numerical invariants associated with molecular structures and are helpful in featuring many properties. Among these molecular descriptors, the eccentricity connectivity index has a dynamic role due to its ability of estimating pharmaceutical properties. In this article, eccentric connectivity, total eccentricity connectivity, augmented eccentric connectivity, first Zagreb eccentricity, modified eccentric connectivity, second Zagreb eccentricity, and the edge version of eccentric connectivity indices, are computed for the molecular graph of a PolyEThyleneAmidoAmine (PETAA) dendrimer. Moreover, the explicit representations of the polynomials associated with some of these indices are also computed.

scholarly journals On molecular topological properties of diamond-like networks

2017 ◽  
Vol 95 (7) ◽  
pp. 758-770 ◽  
Author(s):  
Muhammad Imran ◽  
Abdul Qudair Baig ◽  
Hafiz Muhammad Afzal Siddiqui ◽  
Rabia Sarwar
Keyword(s):  
Molecular Graph ◽  
Topological Indices ◽  
Connectivity Index ◽  
Topological Properties ◽  
Benzenoid Hydrocarbons ◽  
Connectivity Indices

The Randić (product) connectivity index and its derivative called the sum-connectivity index are well-known topological indices and both of these descriptors correlate well among themselves and with the π-electronic energies of benzenoid hydrocarbons. The general n connectivity of a molecular graph G is defined as [Formula: see text] and the n sum connectivity of a molecular graph G is defined as [Formula: see text], where the paths of length n in G are denoted by [Formula: see text] and the degree of each vertex vi is denoted by di. In this paper, we discuss third connectivity and third sum-connectivity indices of diamond-like networks and compute analytical closed results of these indices for diamond-like networks.

scholarly journals Sharp Bounds for the General Sum-Connectivity Indices of Transformation Graphs

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Haiying Wang ◽  
Jia-Bao Liu ◽  
Shaohui Wang ◽  
Wei Gao ◽  
Shehnaz Akhter ◽  
...  
Keyword(s):  
Real Number ◽  
Line Graph ◽  
Connectivity Index ◽  
Point Graph ◽  
Total Graph ◽  
Sharp Bounds ◽  
Graph Transformations ◽  
Degree Of Vertex ◽  
Connectivity Indices ◽  
Distinct Transformation

Given a graph G, the general sum-connectivity index is defined as χα(G)=∑uv∈E(G)dGu+dGvα, where dG(u) (or dG(v)) denotes the degree of vertex u (or v) in the graph G and α is a real number. In this paper, we obtain the sharp bounds for general sum-connectivity indices of several graph transformations, including the semitotal-point graph, semitotal-line graph, total graph, and eight distinct transformation graphs Guvw, where u,v,w∈+,-.

scholarly journals Mathematical Properties of Variable Topological Indices

Symmetry ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 43
Author(s):  
José M. Sigarreta
Keyword(s):  
Real Number ◽  
Large Class ◽  
Symmetric Functions ◽  
Topological Indices ◽  
Current Interest ◽  
Zagreb Indices ◽  
Mathematical Properties ◽  
Connectivity Indices ◽  
Optimal Bounds ◽  
New Framework

A topic of current interest in the study of topological indices is to find relations between some index and one or several relevant parameters and/or other indices. In this paper we study two general topological indices Aα and Bα, defined for each graph H=(V(H),E(H)) by Aα(H)=∑ij∈E(H)f(di,dj)α and Bα(H)=∑i∈V(H)h(di)α, where di denotes the degree of the vertex i and α is any real number. Many important topological indices can be obtained from Aα and Bα by choosing appropriate symmetric functions and values of α. This new framework provides new tools that allow to obtain in a unified way inequalities involving many different topological indices. In particular, we obtain new optimal bounds on the variable Zagreb indices, the variable sum-connectivity index, the variable geometric-arithmetic index and the variable inverse sum indeg index. Thus, our approach provides both new tools for the study of topological indices and new bounds for a large class of topological indices. We obtain several optimal bounds of Aα (respectively, Bα) involving Aβ (respectively, Bβ). Moreover, we provide several bounds of the variable geometric-arithmetic index in terms of the variable inverse sum indeg index, and two bounds of the variable inverse sum indeg index in terms of the variable second Zagreb and the variable sum-connectivity indices.

scholarly journals An algebraic proof of the real number PCP theorem

2017 ◽  
Vol 40 ◽  
pp. 34-77 ◽  
Author(s):  
Martijn Baartse ◽  
Klaus Meer
Keyword(s):  
Real Number ◽  
Algebraic Proof ◽  
The Real ◽  
Pcp Theorem

scholarly journals II. On the Number of the Lost Books of Tacitus. By the Lord Mahon

Archaeologia ◽  
1838 ◽  
Vol 27 ◽  
pp. 15-17
Author(s):  
Mahon
Keyword(s):  
Real Number ◽  
The Real

The historical works of Tacitus which remain to us are, as is well known, besides the Life of Agricola, the four first books of the Annals, part of the fifth, the sixth, the eleventh, twelfth, thirteenth, fourteenth, fifteenth, and part of the sixteenth, the four first books of the History, and part of the fifth. It is asserted by Brotier, in his excellent edition, that the total number of books must have been sixteen of Annals and fourteen of History, and this assertion has never yet, so far as I know, been doubted or called in question. I think, however, that there are strong grounds for presuming that the real number of books was eighteen of Annals and twelve of History; and, though the point be of small importance, it may perhaps not be without some interest to the admirers of the greatest of Historians.

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