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相关论文: New Lower Bounds for the First Variable Zagreb Ind…

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In this paper we obtain bounds on a very general class of distance-based topological indices of graphs, which includes the Wiener index, defined as the sum of the distances between all pairs of vertices of the graph, and most…

组合数学 · 数学 2024-11-21 Peter Dankelmann

In this paper, we present a dynamic programming approach for identifying extremal polyomino chains with respect to degree-based topological indices. This approach provides an explicit recurrence and constructive algorithm that enables both…

组合数学 · 数学 2025-09-16 Manuel Montes-y-Morales , Saylé Sigarreta , Hugo Cruz-Suárez

In this paper a new graph invariant based on the minimal hitting set problem is introduced. It is shown that it represents a tight lower bound for the doubly metric dimension of a graph. Exact values of new invariant for paths, stars,…

组合数学 · 数学 2023-10-11 Jozef Kratica , Vera Kovačević-Vujčić , Mirjana Čangalović

The complementary second Zagreb index of a graph $G$ is defined as $cM_2(G)=\sum_{uv\in E(G)}|(d_u(G))^2-(d_v(G))^2|$, where $d_u(G)$ denotes the degree of a vertex $u$ in $G$ and $E(G)$ represents the edge set of $G$. Let $G^*$ be a graph…

组合数学 · 数学 2025-01-03 Hicham Saber , Tariq Alraqad , Akbar Ali , Abdulaziz M. Alanazi , Zahid Raza

Let $D=(V,A)$ be a digraphs without isolated vertices. A vertex-degree based invariant $I(D)$ related to a real function $\varphi$ of $D$ is defined as a summation over all arcs, $I(D) = \frac{1}{2}\sum_{uv\in A}{\varphi(d_u^+,d_v^-)}$,…

组合数学 · 数学 2021-05-03 Hanyuan Deng , Jiaxiang Yang , Zikai Tang , Jing Yang , Meiling You

In this paper, we investigate the Diminished Sombor index (DSO), a recently introduced degree-based topological index for a simple graph $G$, defined as \[ DSO(G) = \sum_{uv \in E} \frac{\sqrt{d_u^2+d_v^2}}{d_u+d_v}, \] where $d_u$ denotes…

组合数学 · 数学 2025-08-12 F. Movahedi

This paper investigates topological indices for the greedy tree $\mathcal{T}_\mathscr{D}$ associated with a graphic degree sequence $\mathscr{D} = (d_1 \geqslant d_2 \geqslant \dots \geqslant d_n)$ of a tree. A fundamental challenge in the…

综合数学 · 数学 2026-02-05 Jasem Hamoud , Duaa Abdullah

We study topological Poincar\'e type inequalities on general graphs. We characterize graphs satisfying such inequalities and then turn to the best constants in these inequalities. Invoking suitable metrics we can interpret these constants…

泛函分析 · 数学 2018-01-30 Daniel Lenz , Marcel Schmidt , Peter Stollmann

We improve recent results relating graph eigenvalues to other graph parameters like girth, domination number, and minimum degree.

组合数学 · 数学 2007-05-23 Vladimir Nikiforov

Let $G$ be a connected graph. The edge revised Szeged index of $G$ is defined as $Sz^{\ast}_{e}(G)=\sum\limits_{e=uv\in E(G)}(m_{u}(e|G)+\frac{m_{0}(e|G)}{2})(m_{v}(e|G)+\frac{m_{0}(e|G)}{2})$, where $m_{u}(e|G)$ (resp., $m_{v}(e|G)$) is…

组合数学 · 数学 2018-04-18 Shengjie He , Rong-Xia Hao , Deming Li

We give an improvement of a result of Zverovich and Zverovich which gives a condition on the first and last elements in a decreasing sequence of positive integers for the sequence to be graphic, that is, the degree sequence of a finite…

组合数学 · 数学 2013-03-12 Grant Cairns , Stacey Mendan

In this paper, we prove a collection of results on graphical indices. We determine the extremal graphs attaining the maximal generalized Wiener index (e.g. the hyper-Wiener index) among all graphs with given matching number or independence…

组合数学 · 数学 2023-06-22 Stijn Cambie

The Steklov eigenvalue problem was introduced over a century ago, and its discrete form attracted interest recently. Let $D$ and $\delta \Omega$ be the maximum vertex degree and the set of vertices of degree one in a graph $\mathcal{G}$…

组合数学 · 数学 2025-07-01 Huiqiu Lin , Da Zhao

In this manuscript, we delve into the exploration of the first and second Zagreb connection indices of both polyomino chains and random polyomino chains. Our methodology relies on the utilization of Markov chain theory. Within this…

无序系统与神经网络 · 物理学 2024-05-22 Sayle Sigarreta , Hugo Cruz-Suarez

It is well-known that in finite graphs, large complete minors/topological minors can be forced by assuming a large average degree. Our aim is to extend this fact to infinite graphs. For this, we generalise the notion of the relative end…

组合数学 · 数学 2011-02-03 Maya Stein , José Zamora

The arithmetic-geometric index is a newly proposed degree-based graph invariant in mathematical chemistry. We give a sharp upper bound on the value of this invariant for connected chemical graphs of given order and size and characterize the…

The revised Szeged index of a graph $G$ is defined as $Sz^*(G)=\sum_{e=uv \in E}(n_u(e)+ n_0(e)/2)(n_v(e)+ n_0(e)/2),$ where $n_u(e)$ and $n_v(e)$ are, respectively, the number of vertices of $G$ lying closer to vertex $u$ than to vertex…

组合数学 · 数学 2013-07-02 Lily Chen , Xueliang Li , Mengmeng Liu

Let $G=(V,E)$ be a simple graph. The concept of Inverse symmetric division deg index $(ISDD)$ was introduced in the chemical graph theory very recently. In spite of this, a few papers have already appeared with this index in the literature.…

组合数学 · 数学 2024-08-13 Kinkar Chandra Das , B. R. Rakshith , Wojciech Macek

Let $A(G)$ be the adjacency matrix and $D(G)$ be the diagonal matrix of the vertex degrees of a simple connected graph $G$. Nikiforov defined the matrix $A_{\alpha}(G)$ of the convex combinations of $D(G)$ and $A(G)$ as…

组合数学 · 数学 2021-07-20 S. Pirzada , Bilal A. Rather , Hilal A. Ganie , Rezwan ul Shaban

Let $G = (V(G), E(G))$ be a graph. The maximum cardinality of a set $M_k \subseteq E(G)$ such that $M_k$ contains exactly $k$-pairs of adjacent edges of $G$ is called the $k$-nearly edge independence number of $G$, and is denoted by…

组合数学 · 数学 2024-07-15 Zekhaya B. Shozi