On the difference between atom-bond connectivity index and Randić index of binary and chemical trees

2017 ◽  
Vol 117 (23) ◽  
pp. e25446 ◽  
Author(s):  
Akbar Ali ◽  
Zhibin Du
Keyword(s):  
Connectivity Index ◽  
Randić Index ◽  
Randic Index ◽  
The Difference ◽  
Atom Bond ◽  
Chemical Trees

scholarly journals Extremal Trees with Respect to the Difference between Atom-Bond Connectivity Index and Randić Index

Symmetry ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 1591
Author(s):  
Wan Nor Nabila Nadia Wan Zuki ◽  
Zhibin Du ◽  
Muhammad Kamran Jamil ◽  
Roslan Hasni
Keyword(s):  
Graph Theory ◽  
Connectivity Index ◽  
Randić Index ◽  
Extremal Graphs ◽  
Randic Index ◽  
Chemical Graph Theory ◽  
The Difference ◽  
Atom Bond ◽  
Chemical Trees

Let G be a simple, connected and undirected graph. The atom-bond connectivity index (ABC(G)) and Randić index (R(G)) are the two most well known topological indices. Recently, Ali and Du (2017) introduced the difference between atom-bond connectivity and Randić indices, denoted as ABC−R index. In this paper, we determine the fourth, the fifth and the sixth maximum chemical trees values of ABC−R for chemical trees, and characterize the corresponding extremal graphs. We also obtain an upper bound for ABC−R index of such trees with given number of pendant vertices. The role of symmetry has great importance in different areas of graph theory especially in chemical graph theory.

scholarly journals Ordering of alkane isomers by means of connectivity indices

2002 ◽  
Vol 67 (2) ◽  
pp. 87-97 ◽  
Author(s):  
Ivan Gutman ◽  
Dusica Vidovic ◽  
Anka Nedic
Keyword(s):  
Carbon Atom ◽  
Organic Molecule ◽  
Molecular Graph ◽  
Connectivity Index ◽  
Randić Index ◽  
Randic Index ◽  
Connectivity Indices ◽  
The Difference

The connectivity index of an organic molecule whose molecular graph is Gis defined as C(?)=?(?u?v)??where ?u is the degree of the vertex u in G, where the summation goes over all pairs of adjacent vertices of G and where ? is a pertinently chosen exponent. The usual value of ? is ?1/2, in which case ?=C(?1/2) is referred to as the Randic index. The ordering of isomeric alkanes according to ??follows the extent of branching of the carbon-atom skeleton. We now study the ordering of the constitutional isomers of alkanes with 6 through 10 carbon atoms with respect to C(?) for various values of the parameter ?. This ordering significantly depends on ?. The difference between the orderings with respect to ??and with respect to C(?) is measured by a function ??and the ?-dependence of ??was established.

scholarly journals Study of Hardness of Superhard Crystals by Topological Indices

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Xiujun Zhang ◽  
Muhammad Naeem ◽  
Abdul Qudair Baig ◽  
Manzoor Ahmad Zahid
Keyword(s):  
Molecular Structure ◽  
Chemical Structure ◽  
Topological Indices ◽  
Connectivity Index ◽  
Chemical Bonds ◽  
Randić Index ◽  
Total Resistance ◽  
Randic Index ◽  
Atom Bond

Topological indices give immense information about a molecular structure or chemical structure. The hardness of materials for the indentation can be defined microscopically as the total resistance and effect of chemical bonds in the respective materials. The aim of this paper is to study the hardness of some superhard B C x crystals by means of topological indices, specifically Randić index and atom-bond connectivity index.

scholarly journals Inequalities on the Generalized ABC Index

Mathematics ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 1151
Author(s):  
Paul Bosch ◽  
Edil D. Molina ◽  
José M. Rodríguez ◽  
José M. Sigarreta
Keyword(s):  
Hölder Inequality ◽  
Connectivity Index ◽  
Randić Index ◽  
Randic Index ◽  
General Randić Index ◽  
Abc Index ◽  
General Randic Index ◽  
Atom Bond

In this work, we obtained new results relating the generalized atom-bond connectivity index with the general Randić index. Some of these inequalities for ABCα improved, when α=1/2, known results on the ABC index. Moreover, in order to obtain our results, we proved a kind of converse Hölder inequality, which is interesting on its own.

Molecular connectivity indices revisited

1990 ◽  
Vol 55 (3) ◽  
pp. 630-633 ◽  
Author(s):  
Milan Kunz
Keyword(s):  
Adjacency Matrix ◽  
Connectivity Index ◽  
Regular Graphs ◽  
Randić Index ◽  
Molecular Connectivity ◽  
Randic Index ◽  
Molecular Connectivity Indices ◽  
Connectivity Indices

It is shown that the product νiνj of degrees ν of vertices ij, incident with the edge ij, is the number of paths of length 1, 2, and 3 in which the edge is in the center. The unified connectivity index χm = Σ(νiνj)m, where the sum is made over all edges, with m = 1, is the sum of the number of edges, the Platt number and the polarity number. And it is identical with the half sum of the cube A3 of the adjacency matrix A. The Randić index χ-1/2 of regular graphs does not depend on their connectivity.

Functions on adjacent vertex degrees of trees with given degree sequence

2014 ◽  
Vol 12 (11) ◽  
Author(s):  
Hua Wang
Keyword(s):  
Symmetric Function ◽  
Degree Sequence ◽  
Connectivity Index ◽  
Adjacent Vertex ◽  
Randić Index ◽  
Graph Invariant ◽  
Harmonic Index ◽  
Randic Index ◽  
Special Cases ◽  
Vertex Degrees

AbstractIn this note we consider a discrete symmetric function f(x, y) where $$f(x,a) + f(y,b) \geqslant f(y,a) + f(x,b) for any x \geqslant y and a \geqslant b,$$ associated with the degrees of adjacent vertices in a tree. The extremal trees with respect to the corresponding graph invariant, defined as $$\sum\limits_{uv \in E(T)} {f(deg(u),deg(v))} ,$$ are characterized by the “greedy tree” and “alternating greedy tree”. This is achieved through simple generalizations of previously used ideas on similar questions. As special cases, the already known extremal structures of the Randic index follow as corollaries. The extremal structures for the relatively new sum-connectivity index and harmonic index also follow immediately, some of these extremal structures have not been identified in previous studies.

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