نتایج جستجو برای: peripheral wiener index

تعداد نتایج: 577726  

Journal: :Discussiones Mathematicae Graph Theory 2008
Rangaswami Balakrishnan S. Francis Raj

The Wiener number of a graph G is defined as 1 2 ∑ d(u, v), where u, v ∈ V (G), and d is the distance function on G. The Wiener number has important applications in chemistry. We determine the Wiener number of an important family of graphs, namely, the Kneser graphs.

2006
Weigen Yan Yeong-Nan Yeh

Let T be an acyclic molecule with n vertices, and let S(T ) be the acyclic molecule obtained from T by replacing each edge of T by a path of length two. In this work, we show that the Wiener index of T can be explained as the number of matchings with n− 2 edges in S(T ). Furthermore, some related results are also obtained.

Ante Graovac, Franco Cataldo, Ottorino Ori, Tomislav Doslic,

We present explicit formulae for the eccentric connectivity index and Wiener index of 2-dimensional square and comb lattices with open ends. The formulae for these indices of 2-dimensional square lattices with ends closed at themselves are also derived. The index for closed ends case divided by the same index for open ends case in the limit N →&infin defines a novel quantity we call compression...

Journal: :Discrete Applied Mathematics 1997
Wen-Chung Huang Bo-Yin Yang Yeong-Nan Yeh

An explicit, non-recursive formula for the Wiener index of any given benzenoid chain is derived, greatly speeding up calculations and rendering it manually manageable, through a novel envisioning of chains as ternary strings. Previous results are encompassed and two completely new and useful ones are obtained, a formula to determine Wiener indices of benzenoid chains in periodic patterns, and a...

2013
L. CHEN Alireza Abdollahi

Hansen et. al., using the AutoGraphiX software package, conjectured that the Szeged index Sz(G) and the Wiener index W (G) of a connected bipartite graph G with n ≥ 4 vertices and m ≥ n edges, obeys the relation Sz(G) − W (G) ≥ 4n − 8. Moreover, this bound would be the best possible. This paper offers a proof to this conjecture.

Journal: :Eur. J. Comb. 2009
M. H. Khalifeh Hassan Yousefi-Azari Ali Reza Ashrafi Stephan G. Wagner

We study distance-based graph invariants, such as the Wiener index, the Szeged index, and variants of these two. Relations between the various indices for trees are provided as well as formulas for line graphs and product graphs. This allows us, for instance, to establish formulas for the edge Wiener index of Hamming graphs, C4nanotubes and C4-nanotori. We also determine minimum and maximum of ...

Journal: :Discrete Applied Mathematics 2005
Sergey Bereg Hao Wang

Molecules and molecular compounds are often modeled by molecular graphs. One of the most widely known topological descriptor [6, 9] is the Wiener index named after chemist Harold Wiener [13]. The Wiener index of a graph G(V, E) is defined as W (G) = ∑ u,v∈V d(u, v), where d(u, v) is the distance between vertices u and v (minimum number of edges between u and v). A majority of the chemical appli...

Journal: :Discrete Mathematics & Theoretical Computer Science 2017
Huihui Zhang Jing Chen Shuchao Li

Let Sz(G), Sz(G) and W (G) be the Szeged index, revised Szeged index and Wiener index of a graph G. In this paper, the graphs with the fourth, fifth, sixth and seventh largest Wiener indices among all unicyclic graphs of order n > 10 are characterized; and the graphs with the first, second, third, and fourth largest Wiener indices among all bicyclic graphs are identified. Based on these results...

F. WEI Y. WU Z. JIA

Let G be a simple connected graph. The generalized polarity Wiener index of G is defined as the number of unordered pairs of vertices of G whose distance is k. Some formulas are obtained for computing the generalized polarity Wiener index of the Cartesian product and the tensor product of graphs in this article.

H. YONG WANG I. GUTMAN J. QIN

The Wiener index is the sum of distances between all pairs of vertices in a connected graph. In this paper, explicit expressions for the expected value of the Wiener index of three types of random pentagonal chains (cf. Figure 1) are obtained.

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