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We analyse graphs in which each vertex is assigned random coordinates in a geometric space of arbitrary dimensionality and only edges between adjacent points are present. The critical connectivity is found numerically by examining the size…

Statistical Mechanics · Physics 2009-11-07 Jesper Dall , Michael Christensen

Let $G$ be a (multi)graph of order $n$ and let $u,v$ be vertices of $G$. The maximum number of internally disjoint $u$-$v$ paths in $G$ is denoted by $\kappa_G(u,v)$, and the maximum number of edge-disjoint $u$-$v$ paths in $G$ is denoted…

Combinatorics · Mathematics 2018-10-25 Rocío M. Casablanca , Lucas Mol , Ortrud R. Oellermann

Let $G$ be a group. The power graph of $G$ is a graph with vertex set $G$ in which two distinct elements $x,y$ are adjacent if one of them is a power of the other. We characterize all groups whose power graphs have finite independence…

Combinatorics · Mathematics 2019-10-16 P. J. Cameron , S. H. Jafari

We investigate the bounds on algebraic connectivity of graphs subject to constraints on the number of edges, vertices, and topology. We show that the algebraic connectivity for any tree on $n$ vertices and with maximum degree $d$ is bounded…

Discrete Mathematics · Computer Science 2014-12-22 Theodore Kolokolnikov

A $k$-weak bisection of a cubic graph $G$ is a partition of the vertex-set of $G$ into two parts $V_1$ and $V_2$ of equal size, such that each connected component of the subgraph of $G$ induced by $V_i$ ($i=1,2$) is a tree of at most $k-2$…

Combinatorics · Mathematics 2017-09-15 Louis Esperet , Giuseppe Mazzuoccolo , Michael Tarsi

Let $Z_2\times Z_2=\{0, \alpha, \beta, \alpha+\beta\}$. If $G$ is a bridgeless cubic graph, $F$ is a perfect matching of $G$ and $\overline{F}$ is the complementary 2-factor of $F$, then a no-where zero $Z_2\times Z_2$-flow $\theta$ of…

Combinatorics · Mathematics 2025-04-29 Vahan Mkrtchyan

Connectivity is a central notion of graph theory and plays an important role in graph algorithm design and applications. With emerging new applications in networks, a new type of graph connectivity problem has been getting more…

Discrete Mathematics · Computer Science 2020-12-22 Rupei Xu , Warren Shull

We show that we can assume graphs that do not have the edge-Erd\H{o}s-P\'{o}sa property to be connected. Then we strengthen this result to $2$-connectivity under the additional assumptions of a minor-closed property and a generic…

Combinatorics · Mathematics 2023-07-24 Raphael Steck

The Zero divisor Graph of a commutative ring $R$, denoted by $\Gamma[R]$, is a graph whose vertices are non-zero zero divisors of $R$ and two vertices are adjacent if their product is zero. In this paper we derive the Vertex and Edge…

Rings and Algebras · Mathematics 2018-07-11 B. Surendranath Reddy , Rupali. S. Jain , N. Laxmikanth

We study the problem of extracting a selective connector for a given set of query vertices $Q \subseteq V$ in a graph $G = (V,E)$. A selective connector is a subgraph of $G$ which exhibits some cohesiveness property, and contains the query…

Social and Information Networks · Computer Science 2017-09-06 Natali Ruchansky , Francesco Bonchi , David Garcia-Soriano , Francesco Gullo , Nicolas Kourtellis

There are many major open problems in integer flow theory, such as Tutte's 3-flow conjecture that every 4-edge-connected graph admits a nowhere-zero 3-flow, Jaeger et al.'s conjecture that every 5-edge-connected graph is $Z_3$-connected and…

Combinatorics · Mathematics 2015-07-13 Fuyuan Chen , Bo Ning

The Erd\H{o}s-S\'os conjecture states that the maximum number of edges in an $n$-vertex graph without a given $k$-vertex tree is at most $\frac {n(k-2)}{2}$. Despite significant interest, the conjecture remains unsolved. Recently, Caro,…

Combinatorics · Mathematics 2024-02-21 Suyun Jiang , Hong Liu , Nika Salia

A matching $M$ in a graph $G$ is {\em connected} if $G$ has an edge linking each pair of edges in $M$. The problem to find large connected matchings in graphs $G$ with $\alpha(G)=2$ is closely related to Hadwiger's conjecture for graphs…

Combinatorics · Mathematics 2024-09-11 Rong Chen , Zijian Deng

Almost $4$-connectivity is a weakening of $4$-connectivity which allows for vertices of degree three. In this paper we prove the following theorem. Let $G$ be an almost $4$-connected triangle-free planar graph, and let $H$ be an almost…

Combinatorics · Mathematics 2019-05-23 Sergey Norin , Robin Thomas

By definition, the edge-connectivity of a connected graph is no larger than its minimum degree. In this paper, we prove that the edge connectivity of a finite connected graph with non-negative Lin-Lu-Yau curvature is equal to its minimum…

Combinatorics · Mathematics 2026-04-13 Shiping Liu , Qing Xia

The power graph of a group $G$ is the graph whose vertex set is $G$ and two distinct vertices are adjacent if one is a power of the other. This paper investigates the minimal separating sets of power graphs of finite groups. For power…

Combinatorics · Mathematics 2017-03-28 Ramesh Prasad Panda , K. V. Krishna

This article settles Problem 7.2 posed by [Banerjee, Special Matrices (2022)] for the induced subgraph $G_2$ of the comaximal graph $\Gamma(\mathbb Z_n)$ when $n$ is squarefree. Let $n=p_1p_2\cdots p_m$ with distinct primes…

Combinatorics · Mathematics 2026-05-05 Bilal Ahmad Rather

We associate a graph $\mathcal{C}_G$ to a non locally cyclic group $G$ (called the non-cyclic graph of $G$) as follows: take $G\backslash Cyc(G)$ as vertex set, where $Cyc(G)=\{x\in G | < x,y> \text{is cyclic for all} y\in G\}$ is called…

Group Theory · Mathematics 2008-10-03 Alireza Abdollahi , A. Mohammadi Hassanabadi

This paper deals with the vertex connectivity of enhanced power graph of finite group. We classify all abelian groups G such that vertex connectivity of enhanced power graph of G is 1. We derive an upper bound of vertex connectivity for the…

Combinatorics · Mathematics 2020-07-08 Sudip Bera , Hiranya Kishore Dey , Sajal Kumar Mukherjee

Given a zero-sum function $\beta : V(G) \rightarrow \mathbb{Z}_3$ with $\sum_{v\in V(G)}\beta(v)=0$, an orientation $D$ of $G$ with $d^+_D(v)-d^-_D(v)= \beta(v)$ in $\mathbb{Z}_3$ for every vertex $v\in V(G)$ is called a…

Combinatorics · Mathematics 2016-10-17 Miaomiao Han , Hong-Jian Lai , Jiaao Li