scholarly journals Some distance based indices of graphs based on four new operations related to the lexicographic product

2019 ◽  
Vol 11 (2) ◽  
pp. 258-267
Author(s):  
N. Dehgardi ◽  
S.M. Sheikholeslami ◽  
M. Soroudi

For a (molecular) graph, the Wiener index, hyper-Wiener index and degree distance index are defined as $$W(G)= \sum_{\{u,v\}\subseteq V(G)}d_G(u,v),$$ $$WW(G)=W(G)+\sum_{\{u,v\}\subseteq V(G)} d_{G}(u,v)^2,$$ and $$DD(G)=\sum_{\{u,v\}\subseteq V(G)}d_G(u, v)(d(u/G)+d(v/G)),$$ respectively, where $d(u/G)$ denotes the degree of a vertex $u$ in $G$ and $d_G(u, v)$ is distance between two vertices $u$ and $v$ of a graph $G$. In this paper, we study Wiener index, hyper-Wiener index and degree distance index of graphs based on four new operations related to the lexicographic product, subdivision and total graph.

Filomat ◽  
2014 ◽  
Vol 28 (3) ◽  
pp. 579-590 ◽  
Author(s):  
Mingqiang An ◽  
Liming Xiong ◽  
Kinkar Das

The degree distance (DD), which is a weight version of the Wiener index, defined for a connected graph G as vertex-degree-weighted sum of the distances, that is, DD(G) = ?{u,v}?V(G)[dG(u)+dG(v)]d[u,v|G), where dG(u) denotes the degree of a vertex u in G and d(u,v|G) denotes the distance between two vertices u and v in G: In this paper, we establish two upper bounds for the degree distances of four sums of two graphs in terms of other indices of two individual graphs.


Mathematics ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 359
Author(s):  
Hassan Ibrahim ◽  
Reza Sharafdini ◽  
Tamás Réti ◽  
Abolape Akwu

Let G be a connected (molecular) graph with the vertex set V(G)={v1,⋯,vn}, and let di and σi denote, respectively, the vertex degree and the transmission of vi, for 1≤i≤n. In this paper, we aim to provide a new matrix description of the celebrated Wiener index. In fact, we introduce the Wiener–Hosoya matrix of G, which is defined as the n×n matrix whose (i,j)-entry is equal to σi2di+σj2dj if vi and vj are adjacent and 0 otherwise. Some properties, including upper and lower bounds for the eigenvalues of the Wiener–Hosoya matrix are obtained and the extremal cases are described. Further, we introduce the energy of this matrix.


2002 ◽  
Vol 57 (1-2) ◽  
pp. 49-51
Author(s):  
Miranca Fischermann ◽  
Ivan Gutman ◽  
Arne Hoffmann ◽  
Dieter Rautenbach ◽  
Dušica Vidovića ◽  
...  

A variety of molecular-graph-based structure-descriptors were proposed, in particular the Wiener index W. the largest graph eigenvalue λ1, the connectivity index X, the graph energy E and the Hosoya index Z, capable of measuring the branching of the carbon-atom skeleton of organic compounds, and therefore suitable for describing several of their physico-chemical properties. We now determine the structure of the chemical trees (= the graph representation of acyclic saturated hydrocarbons) that are extremal with respect to W , λ1, E, and Z. whereas the analogous problem for X was solved earlier. Among chemical trees with 5. 6, 7, and 3k + 2 vertices, k = 2,3,..., one and the same tree has maximum λ1 and minimum W, E, Z. Among chemical trees with 3k and 3k +1 vertices, k = 3,4...., one tree has minimum 11 and maximum λ1 and another minimum E and Z .


1994 ◽  
Vol 34 (5) ◽  
pp. 1082-1086 ◽  
Author(s):  
Andrey A. Dobrynin ◽  
Amide A. Kochetova
Keyword(s):  

2017 ◽  
Vol 63 ◽  
pp. 485-495
Author(s):  
Sheela Suthar ◽  
Om Prakash
Keyword(s):  

2012 ◽  
Vol 02 (04) ◽  
pp. 156-159 ◽  
Author(s):  
Daniel Gray ◽  
Hua Wang
Keyword(s):  

2019 ◽  
Vol 11 (04) ◽  
pp. 1950045
Author(s):  
K. Pattabiraman ◽  
Manzoor Ahmad Bhat

The product degree distance of a connected graph [Formula: see text] is defined as [Formula: see text] where [Formula: see text] is the degree of a vertex [Formula: see text] and [Formula: see text] is the distance between the vertices [Formula: see text] and [Formula: see text] in [Formula: see text] In this paper, we obtain two upper bounds for product degree distance of [Formula: see text]-sums of graphs which is defined by Eliasi [Four new sums of graphs and their Wiener indices, Discr. Appl. Math. 157 (2009) 794–803.]


2008 ◽  
Vol 73 (3) ◽  
pp. 311-319 ◽  
Author(s):  
Mehdi Eliasi ◽  
Bijan Taeri

The Hosoya polynomial of a molecular graph G is defined as H(G,?)=?{u,v}V?(G) ?d(u,v), where d(u,v) is the distance between vertices u and v. The first derivative of H(G,?) at ?=1 is equal to the Wiener index of G, defined as W(G)?{u,v}?V(G)d(u,v). The second derivative of 1/2 ?H(G, ?) at ?=1 is equal to the hyper-Wiener index, defined as WW(G)+1/2?{u,v}?V(G)d(u,v)?. Xu et al.1 computed the Hosoya polynomial of zigzag open-ended nanotubes. Also Xu and Zhang2 computed the Hosoya polynomial of armchair open-ended nanotubes. In this paper, a new method was implemented to find the Hosoya polynomial of G = HC6[p,q], the zigzag polyhex nanotori and to calculate the Wiener and hyper Wiener indices of G using H(G,?).


2021 ◽  
Vol 51 (4) ◽  
Author(s):  
M. Gholamnia Taleshani ◽  
Ahmad Abbasi
Keyword(s):  

2014 ◽  
Vol 8 ◽  
pp. 4217-4226
Author(s):  
Mohamed Essalih ◽  
Mohamed El Marraki ◽  
Abd Errahmane Atmani
Keyword(s):  

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