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We resolve two conjectures of Hri\v{n}\'{a}kov\'{a}, Knor and \v{S}krekovski (2019) concerning the relationship between the variable Wiener index and variable Szeged index for a connected, non-complete graph, one of which would imply the…

Combinatorics · Mathematics 2023-03-22 Stijn Cambie , John Haslegrave

Let $G(V, E)$ be a simple connected graph, with $|E| = \epsilon.$ In this paper, we define an edge-set graph $\mathcal G_G$ constructed from the graph $G$ such that any vertex $v_{s,i}$ of $\mathcal G_G$ corresponds to the $i$-th…

General Mathematics · Mathematics 2023-07-19 Johan Kok , N. K. Sudev , K. P. Chithra

The Wiener index W(G) of a connected graph $G$ is the sum of distances between all pairs of vertices in G$. In this paper, we first give the recurrences or explicit formulae for computing the Wiener indices of spiro and polyphenyl hexagonal…

Combinatorics · Mathematics 2010-06-30 Hanyuan Deng

Let ${\cal G}=(G,w)$ be a weighted simple finite connected graph, that is, let $G$ be a simple finite connected graph endowed with a function $w$ from the set of the edges of $G$ to the set of real numbers. For any subgraph $G'$ of $G$, we…

Combinatorics · Mathematics 2014-12-18 Elena Rubei

Topological indices are parameters associated with graphs that have many applications in different areas such as mathematical chemistry. Among various topological indices, the Wiener index is classical \cite{w}. In this paper, we prove a…

Combinatorics · Mathematics 2023-03-23 P. Gangaeswari , K. Selvakumar , G. Arunkumar

We show that on cactus graphs the Szeged index is bounded above by twice the Wiener index. For the revised Szeged index the situation is reversed if the graph class is further restricted. Namely, if all blocks of a cactus graph are cycles,…

Combinatorics · Mathematics 2022-11-15 Stefan Hammer

B. Szegedy [Edge coloring models and reflection positivity, {\sl Journal of the American Mathematical Society} {\bf 20} (2007) 969--988] showed that the number of homomorphisms into a weighted graph is equal to the partition function of a…

Combinatorics · Mathematics 2014-09-17 Guus Regts

The status of a vertex $u$ in a connected graph $G$, denoted by $\sigma_G(u)$, is defined as the sum of the distances between $u$ and all other vertices of a graph $G$. The first and second status connectivity indices of a graph $G$ are…

Combinatorics · Mathematics 2016-11-28 Harishchandra S. Ramane , Ashwini S. Yalnaik , Reza Sharafdini

The forgotten topological index of a graph $G$, denoted by $F(G)$, is defined as the sum of weights $d(u)^{2}+d(v)^{2}$ over all edges $uv$ of $G$ , where $d(u)$ denotes the degree of a vertex $u$. In this paper, we give sharp upper bounds…

Combinatorics · Mathematics 2021-02-05 A. Jahanbani , L. Shahbazi , S. M. Sheikholeslami , R. Rasi , J. Rodriguez

The Wiener index of a graph $G$, denoted $W(G)$, is the sum of the distances between all pairs of vertices in $G$. \'E. Czabarka, et al. conjectured that for an $n$-vertex, $n\geq 4$, simple quadrangulation graph $G$,…

Combinatorics · Mathematics 2020-01-06 Ervin Győri , Addisu Paulos , Chuanqi Xiao

Let $\mathcal{D}$ be a weighted oriented graph and $I(\mathcal{D})$ be its edge ideal. In this paper, we investigate the Betti numbers of $I(\mathcal{D})$ via upper-Koszul simplicial complexes, Betti splittings and the mapping cone…

Commutative Algebra · Mathematics 2020-09-24 Beata Casiday , Selvi Kara

Motivated by the theorem of Gy\H ori and Lov\'asz, we consider the following problem. For a connected graph $G$ on $n$ vertices and $m$ edges determine the number $P(G,k)$ of unordered solutions of positive integers $\sum_{i=1}^k m_i = m$…

Combinatorics · Mathematics 2023-10-11 Yair Caro , Balázs Patkós , Zsolt Tuza , Máté Vizer

For a molecular graph, the first multiplicative Zagreb index $\Pi_1$ is equal to the product of the square of the degree of the vertices, while the second multiplicative Zagreb index $\Pi_2$ is equal to the product of the endvertex degree…

Combinatorics · Mathematics 2017-05-09 Shaohui Wang , Chunxiang Wang , Lin Chen

This work introduces a novel algorithm for finding the connected components of a graph where the vertices and edges are grouped into sets defining a Set--Based Graph. The algorithm, under certain restrictions on those sets, has the…

Data Structures and Algorithms · Computer Science 2020-11-30 Ernesto Kofman , Denise Marzorati , Joaquín Fernández

We perform a detailed statistical study of the distribution of topological and spectral indices on random graphs $G=(V,E)$ in a wide range of connectivity regimes. First, we consider degree-based topological indices (TIs), and focus on two…

Combinatorics · Mathematics 2026-02-23 C. T. Martínez-Martínez , R. Aguilar-Sánchez , J. A. Méndez-Bermúdez

A weighted graph is a graph in which every edge is assigned a non-negative real number. In a weighted graph, the weight of a path is the sum of the weights of its edges, and the weighed degree of a vertex is the sum of the weights of the…

Combinatorics · Mathematics 2011-11-28 Binlong Li , Shenggui Zhang

The complexity of a graph can be obtained as a derivative of a variation of the zeta function or a partial derivative of its generalized characteristic polynomial evaluated at a point [\textit{J. Combin. Theory Ser. B}, 74 (1998), pp.…

Combinatorics · Mathematics 2010-11-01 Dongseok Kim , Young Soo Kwon , Jaeun Lee

An independent set in a graph G is a set of vertices no two of which are joined by an edge. A vertex-weighted graph associates a weight with every vertex in the graph. A vertex-weighted graph G is called a unique independence…

Computational Complexity · Computer Science 2009-07-02 Farzad Didehvar , Ali D. Mehrabi , Fatemeh Raee B

In this study, we take a systematic look at the unrealised part of public transport networks (PTNs) with functional connections. We consider their complement graphs and study their structure. The complement graph $\bar G$ of an unweighted…

Physics and Society · Physics 2026-04-24 Tina Šfiligoj , Oded Cats

Let $G=(V(G),E(G))$ be a molecular graph, where $V(G)$ and $E(G)$ are the sets of vertices (atoms) and edges (bonds). A topological index of a molecular graph is a numerical quantity which helps to predict the chemical/physical properties…

Combinatorics · Mathematics 2022-04-25 Bo Bi , Muhammad Kamran Jamil , Khawaja Muhammad Fahd , Tian-Le Sun , Imran Ahmad , Lei Ding