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The Kirchhoff index of a connected graph is the sum of resistance distances between all unordered pairs of vertices in the graph. It found considerable applications in a variety of fields. In this paper, we determine the minimum Kirchhoff…

Combinatorics · Mathematics 2017-02-10 Xuli Qi , Bo Zhou , Zhibin Du

In a graph $G$, a subset of vertices $S \subseteq V(G)$ is said to be cyclable if there is a cycle containing the vertices in some order. $G$ is said to be $k$-cyclable if any subset of $k \geq 2$ vertices is cyclable. If any $k$…

Combinatorics · Mathematics 2022-11-28 Niranjan Balachandran , Anish Hebbar

An acyclic edge coloring of a graph is a proper edge coloring without any bichromatic cycles. The acyclic chromatic index of a graph $G$ denoted by $a'(G)$, is the minimum $k$ such that $G$ has an acyclic edge coloring with $k$ colors.…

Combinatorics · Mathematics 2024-01-31 Nevil Anto , Manu Basavaraju , Suresh Manjanath Hegde , Shashanka Kulamarva

We utilize relations between Khovanov and chromatic graph homology to determine extreme Khovanov groups and corresponding coefficients of the Jones polynomial. The extent to which chromatic homology and chromatic polynomial can be used to…

Geometric Topology · Mathematics 2020-03-12 Radmila Sazdanovic , Daniel Scofield

Consider that $\mathbb{G}=(\mathbb{X}, \mathbb{Y})$ is a simple, connected graph with $\mathbb{X}$ as the vertex set and $\mathbb{Y}$ as the edge set. The atom-bond connectivity ($ABC$) index is a novel topological index that Estrada…

General Mathematics · Mathematics 2024-11-20 Waqar Ali , Mohamad Nazri Bin Husin , Muhammad Faisal Nadeem

We investigate several measures of peripherality for vertices and edges in networks. We improve asymptotic bounds on the maximum value achieved by edge peripherality, edge sum peripherality, and the Trinajsti\'c index over $n$ vertex…

Combinatorics · Mathematics 2023-06-29 Linus Tang

The aim of this paper is to obtain new inequalities for a large family of topological indices restricted to unicyclic graphs and to characterize the set of extremal unicyclic graphs with respect to them. This family includes variable first…

Combinatorics · Mathematics 2021-03-16 Álvaro Martínez-Pérez , José M. Rodríguez

For a graph $G$ without isolated vertices, the inverse degree of a graph $G$ is defined as $ID(G)=\sum_{u\in V(G)}d(u)^{-1}$ where $d(u)$ is the number of vertices adjacent to the vertex $u$ in $G$. By replacing $-1$ by any non-zero real…

Combinatorics · Mathematics 2019-09-10 Muhammad Kamran Jamil , Ioan Tomescu , Muhammad Imran

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

We study bond percolation for a family of infinite hyperbolic graphs. We relate percolation to the appearance of homology in finite versions of these graphs. As a consequence, we derive an upper bound on the critical probabilities of the…

Probability · Mathematics 2016-11-29 Nicolas Delfosse , Gilles Zémor

Let $G$ be a simple graph of order $n$, let $\lambda_1(G),\lambda_2(G),...,\lambda_n(G)$ be the eigenvalues of the adjacency matrix of $G$. The Esrada index of $G$ is defined as $EE(G)=\sum_{i=1}^{n}e^{\lambda_i(G)}$. In this paper we…

Combinatorics · Mathematics 2014-09-19 Long Wang , Yi-Zheng Fan , Yi Wang

Let $G$ be a connected graph. The resistance distance between any two vertices of $G$ is equal to the effective resistance between them in the corresponding electrical network constructed from $G$ by replacing each edge with a unit…

Combinatorics · Mathematics 2022-09-22 Qi Ma

For a given connected graph $G$, the edge Mostar index $Mo_e(G)$ is defined as $Mo_e(G)=\sum_{e=uv \in E(G)}|m_u(e|G) - m_v(e|G)|$, where $m_u(e|G)$ and $m_v(e|G)$ are respectively, the number of edges of $G$ lying closer to vertex $u$ than…

Combinatorics · Mathematics 2024-05-21 Fazal Hayat , Shou-Jun Xu , Bo Zhou

The eccentric connectivity index of a graph $G$ is $\xi^c(G) = \sum_{v \in V(G)}\varepsilon(v)\deg(v)$, and the eccentric distance sum is $\xi^d(G) = \sum_{v \in V(G)}\varepsilon(v)D(v)$, where $\varepsilon(v)$ is the eccentricity of $v$,…

Combinatorics · Mathematics 2020-05-07 Yaser Alizadeh , Sandi Klavžar

The concept of geometric-arithmetic index was introduced in the chemical graph theory recently, but it has shown to be useful. The aim of this paper is to obtain new inequalities involving the geometric-arithmetic index $GA_1$ and…

Combinatorics · Mathematics 2017-03-17 Alvaro Martínez-Pérez , José M. Rodríguez

The vertex $k$-partiteness $v_k(G)$ of graph $G$ is defined as the fewest number of vertices whose deletion from $G$ yields a $k$-partite graph. In this paper, we introduce two concepts: monotonic decreasing topological index and monotonic…

Combinatorics · Mathematics 2017-08-04 Fang Gao , Duo Duo Zhao , Xiao-Xin Li , Jia-Bao Liu

Let $q(G)$ denote the $Q$-index of a graph $G$, which is the largest signless Laplacian eigenvalue of $G$. We prove best possible upper bounds of $q(G)$ and best possible lower bounds of $q(\overline{G})$ for a connected graph $G$ to be…

Combinatorics · Mathematics 2019-04-11 Huicai Jia , Hong-Jian Lai , Ruifang Liu , Ju Zhou

Bicyclic graph is a connected graph in which the number of edges equals the number of vertices plus one. In this paper, we determine the graph which alone maximizes the spectral radii among all the bicyclic graphs on $n$ vertices with fixed…

Combinatorics · Mathematics 2014-02-25 Xiying Yuan

The first multiplicative Zagreb index of a graph $G$ is the product of the square of every vertex degree, while the second multiplicative Zagreb index is the product of the degree of each edge over all edges. In our work, we explore the…

Combinatorics · Mathematics 2017-04-28 Chunxiang Wang , Jia-Bao Liu , Shaohui Wang

For a symmetric bivariable function $f(x,y)$, let the {\it connectivity function} of a connected graph $G$ be $M_f(G)=\sum_{uv\in E(G)}f(d(u),d(v))$, where $d(u)$ is the degree of vertex $u$. In this paper, we prove that for an escalating…

Combinatorics · Mathematics 2018-09-07 Muhuo Liu , Kexiang Xu , Xiao-Dong Zhang