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The $M$-polynomial was introduced by Deutsch and Klav\v{z}ar in 2015 as a graph polynomial to provide an easy way to find closed formulas of degree-based topological indices, which are used to predict physical, chemical, and pharmacological…

Combinatorics · Mathematics 2017-08-29 Abdul Rauf Nizami , Muhammad Idrees , Numan Amin

Vulnerability measures and topological indices are crucial in solving various problems such as the stability of the communication networks and development of mathematical models for chemical compounds. In 1947, Harry Wiener introduced a…

Combinatorics · Mathematics 2025-03-06 Sanju Vaidya , Aihua Li

The Hosoya polynomial of a graph encompasses many of its metric properties, for instance the Wiener index (alias average distance) and the hyper-Wiener index. An expression is obtained that reduces the computation of the Hosoya polynomials…

Combinatorics · Mathematics 2012-12-14 Emeric Deutsch , Sandi Klavzar

The Hosoya polynomial is a well known vertex-distance based polynomial, closely correlated to the Wiener index and the hyper-Wiener index, which are widely used molecular-structure descriptors. In the present paper we consider the edge…

Combinatorics · Mathematics 2019-04-09 Niko Tratnik , Petra Žigert Pleteršek

The M-polynomial, introduced by Deutsch and Klav\v{z}ar in 2015, provides a unifying algebraic framework for the computation of numerous degree-based topological indices such as the Zagreb, Randic, harmonic, and forgotten indices. Despite…

Combinatorics · Mathematics 2026-03-31 El-Mehdi Mehiri

Let G be a simple connected graph having vertex set V and edge set E. The vertex-set and edge-set of G denoted by V(G) and E(G), respectively. The length of the smallest path between two vertices is called the distance. Mathematical…

Let $G$ be a graph and let $m_{ij}(G)$, $i,j\ge 1$, be the number of edges $uv$ of $G$ such that $\{d_v(G), d_u(G)\} = \{i,j\}$. The {\em $M$-polynomial} of $G$ is introduced with $\displaystyle{M(G;x,y) = \sum_{i\le j} m_{ij}(G)x^iy^j}$.…

Combinatorics · Mathematics 2014-07-08 Emeric Deutsch , Sandi Klavžar

A graph $G$ on $n$ vertices of diameter $D$ is called $H$-palindromic if $\alpha(G,k) = \alpha(G,D-k)$ for all $k=0, 1, \dots, \left \lfloor{\frac{D}{2}}\right \rfloor$, where $\alpha(G,k)$ is the number of unordered pairs of vertices at…

Combinatorics · Mathematics 2021-12-22 Dmitry Badulin , Alexandr Grebennikov , Konstantin Vorob'ev

In this note we obtain an explicit formula for the Hosoya polynomial of any distance-regular graph in terms of its intersection array. As a consequence, we obtain a very simple formula for the Hosoya polynomial of any strongly regular…

Combinatorics · Mathematics 2013-09-13 Emeric Deutsch , Juan A. Rodriguez-Velazquez

The numerical values extracted from a graph that indicates its topology are called topological indices. A contemporary and efficient method is to compute a graph's topological indices using the graph polynomial that corresponds to it. This…

Discrete Mathematics · Computer Science 2026-02-18 Jayjit Barman , Shibsankar Das

In this paper, we examine roots of graph polynomials where those roots can be considered as structural graph measures. More precisely, we prove analytical results for the roots of certain modified graph polynomials and also discuss…

Combinatorics · Mathematics 2024-11-11 Simon Brezovnik , Matthias Dehmer , Niko Tratnik , Petra Žigert Pleteršek

Given a graph G, an incidence matrix N(G) is defined for the set of distinct isomorphism types of induced subgraphs of G. If Ulam's conjecture is true, then every graph invariant must be reconstructible from this matrix, even when the…

Combinatorics · Mathematics 2007-05-23 Bhalchandra D. Thatte

Gromov-Hausdorff distances measure shape difference between the objects representable as compact metric spaces, e.g. point clouds, manifolds, or graphs. Computing any Gromov-Hausdorff distance is equivalent to solving an NP-Hard…

Computational Geometry · Computer Science 2024-06-07 Vladyslav Oles , Nathan Lemons , Alexander Panchenko

The Hosoya index $Z (G)$ of a graph $G$ is defined as the total number of edge independent sets of $G$. In this paper, we extend the research of [J. Ou, On extremal unicyclic molecular graphs with maximal Hosoya index, \textit{Discrete…

Combinatorics · Mathematics 2011-05-30 Guihai Yu , Lihua Feng , Aleksandar Ilic

The bivariate chromatic polynomial $\chi_G(x,y)$ of a graph $G = (V, E)$, introduced by Dohmen-P\"{o}nitz-Tittmann (2003), counts all $x$-colorings of $G$ such that adjacent vertices get different colors if they are $\le y$. We extend this…

Combinatorics · Mathematics 2024-02-14 Matthias Beck , Sampada Kolhatkar

In this paper, we study the Steiner hyper-Wiener index of a graph, which is obtained from the standard hyper-Wiener index by replacing the classical graph distance with the Steiner distance. It is shown how this index is related to the…

Combinatorics · Mathematics 2018-08-28 Niko Tratnik

A subset of vertices of a graph $G$ is a general position set if no triple of vertices from the set lie on a common shortest path in $G$. In this paper we introduce the general position polynomial as $\sum_{i \geq 0} a_i x^i$, where $a_i$…

Combinatorics · Mathematics 2024-01-12 Vesna Iršič , Sandi Klavžar , Gregor Rus , James Tuite

We consider a graph polynomial \xi(G;x,y,z) introduced by Averbouch, Godlin, and Makowsky (2007). This graph polynomial simultaneously generalizes the Tutte polynomial as well as a bivariate chromatic polynomial defined by Dohmen, Poenitz…

Combinatorics · Mathematics 2008-01-11 Christian Hoffmann

We extend the polynomial approach to hook length formula proposed in a recent joint paper with K\'arolyi, Nagy and Volkov to several other problems of the same type, including number of paths formula in the Young graph of strict partitions.

Combinatorics · Mathematics 2015-04-07 Fedor Petrov

The Wiener index $W(G)$ is the sum of distances of all pairs of vertices of the graph $G$. The Wiener polarity index $W_{p}(G)$ of a graph $G$ is the number of unordered pairs of vertices $u$ and $v$ of $G$ such that the distance…

Combinatorics · Mathematics 2016-03-22 Mohamed Amine Boutiche
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