Wiener Index under Gated Amalgamations
نویسنده
چکیده
Abstract. A subgraph H of a graph G is gated if for every x ∈ V (G) there exists a vertex u in H such that dG(x, v) = dG(x, u) + dG(u, v) for any v ∈ V (H). The gated amalgam of graphs G1 and G2 is obtained from G1 and G2 by identifying their isomorphic gated subgraphs H1 and H2. Two theorems on the Wiener index of gated amalgams are proved. Several known results on the Wiener index of (chemical) graphs are corollaries of these theorems which we demonstrate by gated amalgams of trees and benzenoid systems.
منابع مشابه
Hosoya polynomials under gated amalgamations
An induced subgraph H of a graph G is gated if for every vertex x outside H there exists a vertex x ′ inside H such that each vertex y of H is connected with x by a shortest path passing through x . The gated amalgam of graphs G1 and G2 is obtained from G1 and G2 by identifying their isomorphic gated subgraphs H1 and H2. Two theorems on Hosoya polynomials of gated amalgams are provided. As thei...
متن کاملThe modified Wiener index of some graph operations
Graovac and Pisanski [On the Wiener index of a graph, J. Math. Chem. 8 (1991) 53 – 62] applied an algebraic approach to generalize the Wiener index by symmetry group of the molecular graph under consideration. In this paper, exact formulas for this graph invariant under some graph operations are presented.
متن کاملThe reliability Wiener number of cartesian product graphs
Reliability Wiener number is a modification of the original Wiener number in which probabilities are assigned to edges yielding a natural model in which there are some (or all) bonds in the molecule that are not static. Various probabilities naturally allow modelling different types of chemical bonds because chemical bonds are of different types and it is well-known that under certain condition...
متن کاملThe Second Edge-wiener Index of Some Composite Graphs
In this paper we study the behavior of the second edge-Wiener index under the join and corona product of graphs. Results are applied for some classes of graphs such as suspensions, bottlenecks, and thorny graphs. 2010 Mathematics Subject Classification: 05C12; 05C62; 92E10
متن کاملConstrained Linear Minimum MSE Estimation
We address the problem of linear minimum meansquared error (LMMSE) estimation under constraints on the lter or the estimated signal. We develop a general formula that leads to closed form solutions for a wide class of constrained LMMSE problems. The results are applicable to both nite dimensional problems as well as to the Wiener ltering setup, in which in nitely-many measurements are availabl...
متن کامل