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Let $G=(V,E)$ be a simple graph with $n = |V|$ vertices and $m = |E|$ edges. The first and second Zagreb indices are among the oldest and the most famous topological indices, defined as $M_1 = \sum_{i \in V} d_i^2$ and $M_2 = \sum_{(i, j)…

Combinatorics · Mathematics 2011-04-22 Aleksandar Ilić , Dragan Stevanović

Let $G$ be a simple graph with order $n$ and size $m$. The quantity $M_1(G)=\displaystyle\sum_{i=1}^{n}d^2_{v_i}$ is called the first Zagreb index of $G$, where $d_{v_i}$ is the degree of vertex $v_i$, for all $i=1,2,\dots,n$. The signless…

Combinatorics · Mathematics 2022-05-10 S. Pirzada , Saleem Khan

Szeged, PI and Mostar indices are some of the most investigated distance-based molecular descriptors. Recently, many different variations of these topological indices appeared in the literature and sometimes they are all together called…

Combinatorics · Mathematics 2021-02-15 Simon Brezovnik , Niko Tratnik

Let $\prod(G)$ be Multiplicative Zagreb index of a graph G. A connected graph is a cactus graph if and only if any two of its cycles have at most one vertex in common, which has been the interest of researchers in the filed of material…

Combinatorics · Mathematics 2016-07-19 Shaohui Wang , Bing Wei

The concepts of geometric-arithmetic and harmonic indices were introduced in the area of chemical graph theory recently. They have proven to correlate well with physical and chemical properties of some molecules. The aim of this paper is to…

Combinatorics · Mathematics 2020-04-08 Walter Carballosa , Ana Granados , Domingo Pestana , Ana Portilla , Jose María Sigarreta

Topological indices play an important role in mathematical chemistry especially in the quantitative structure-property relationship (QSPR) and quantitative structure-activity relationship (QSAR). Recent research indicates that the augmented…

Combinatorics · Mathematics 2016-07-26 Akbar Ali , Zahid Raza , Akhlaq Ahmad Bhatti

Applications in chemistry motivated mathematicians to define different topological indices for different types of graphs. The Hyper-Zagreb index (HM) is an important tool as it integrates the first and the second Zagreb indices. In this…

Combinatorics · Mathematics 2018-09-12 Hassan Rezapour , Ramin Nasiri , Seyedahmad Mousavi

Introduced the quantitative measure of the structural complexity of the graph (complex network, etc.) based on a procedure similar to the renormalization process, considering the difference between actual and averaged graph structures on…

Physics and Society · Physics 2024-06-05 A. A. Snarskii

We examine the quantity \[S(G) = \sum_{uv\in E(G)} \min(\text{deg } u, \text{deg } v)\] over sets of graphs with a fixed number of edges. The main result shows the maximum possible value of $S(G)$ is achieved by three different classes of…

Combinatorics · Mathematics 2018-01-09 Ashwin Sah , Mehtaab Sawhney

Making use of a majorization technique for a suitable class of graphs, we derive upper and lower bounds for some topological indices depending on the degree sequence over all vertices, namely the first general Zagreb index and the first…

Combinatorics · Mathematics 2015-03-27 Monica Bianchi , Alessandra Cornaro , José Luis Palacios , Anna Torriero

The Szeged index of a graph is an invariant with several applications in chemistry. The power graph of a finite group $G$ is a graph having vertex set as $G$ in which two vertices $u$ and $v$ are adjacent if $v=u^m$ or $u=v^n$ for some…

Combinatorics · Mathematics 2025-10-30 Subarsha Banerjee

Let $G$ be a connected graph with $n$ vertices and $m$ edges. The vertex-degree-based topological index (VDB) (or graphical function-index) $TI(G)$ of $G$ with edge-weight function $I(x,y)$ is defined as $$TI(G)=\sum\limits_{uv\in…

General Mathematics · Mathematics 2023-04-25 Hechao Liu , Zenan Du , Yufei Huang , Hanlin Chen , Suresh Elumalai

The Steiner distance in a graph, introduced by Chartrand et al. in 1989, is a natural generalization of the concept of classical graph distance. For a connected graph $G$ of order at least 2 and $S\subseteq V(G)$, the Steiner distance…

A vertex-degree-based topological index named as Sombor index of a simple graph G with n vertices was recently introduced by I. Gutman. In this paper, we find Sombor index of m-splitting graph and m-shadow graph. Also, we determine relation…

Combinatorics · Mathematics 2022-05-20 Randhir Singh , S. C. Patekar

The distance $d(u,v)$ between the vertices $u$ and $v$ of a connected graph $G$ is defined as the number of edges in a minimal path connecting them. The \emph{transmission} of a vertex $v$ of $G$ is defined by $\sigma(v)=\sum\limits_{u\in…

Combinatorics · Mathematics 2018-09-18 Reza Sharafdini , Tamas Reti

The Wiener index of a graph $W(G)$ is a well studied topological index for graphs. An outstanding problem of \v{S}olt{\'e}s is to find graphs $G$ such that $W(G)=W(G-v)$ for all vertices $v\in V(G)$, with the only known example being…

Combinatorics · Mathematics 2021-06-23 Sam Spiro

Topological indices are real numbers invariant under graph isomorphisms. Chromatic analogue of topological indices has been introduced recently in literature in 2017. Mainly, chromatic versions of Zagreb indices are studied lately. This…

General Mathematics · Mathematics 2018-10-09 Smitha Rose , Sudev Naduvath

In 2024, Gutman et al. \cite{I.Gutman 3} defined a new molecular descriptor called as The Euler-Sombor $(ES)$ index of graph. By using this index we define the Euler-Sombor $(ES)$ matrix of a graph $G$ whoes $(i,j)^{th}$ entry is…

Combinatorics · Mathematics 2025-02-13 Sopan Bansode , Sharad Barde , Ganesh Mundhe

Let $\mathbb{G} = (\mathcal{V}, \mathcal{E})$ be a simple connected graph, where $\mathcal{V}$ and $\mathcal{E}$ denote the vertex and edge sets, respectively. The first Zagreb index is defined as $\mathcal{M}_{1}(\mathbb{G}) = \sum_{v \in…

General Mathematics · Mathematics 2025-08-08 Waqar Ali , Mohamad Nazri Bin Husin , Muhammad Faisal Nadeem , Muqaddas Jabin

The aim of this paper is to obtain new sharp inequalities for a large family of topological indices, including the first variable Zagreb index $M_1^\alpha$, and to characterize the set of extremal graphs with respect to them. Our main…

Combinatorics · Mathematics 2018-06-07 Alvaro Martínez-Pérez , José M. Rodríguez