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We introduce a method to embed edge-colored graphs into families of expander graphs, which generalizes a framework developed by Dragani\'c, Krivelevich, and Nenadov (2022). As an application, we show that each family of sufficiently…

Combinatorics · Mathematics 2025-01-27 Ben Lund , Chuandong Xu

Associated to a simple undirected graph $G$ is a simplicial complex $\Delta_G$ whose faces correspond to the independent sets of $G$. A graph $G$ is called vertex decomposable if $\Delta_G$ is a vertex decomposable simplicial complex. We…

Commutative Algebra · Mathematics 2009-02-26 Mohammad Mahmoudi , Amir Mousivand , Siamak Yassemi

The connective eccentric index of a graph is a topological index involving degrees and eccentricities of vertices of the graph. In this paper, we have studied the connective eccentric index for double graph and double cover. Also we give…

Combinatorics · Mathematics 2014-06-03 Nilanjan De , Anita Pal , Sk. Md. Abu Nayeem

Given a set of nonempty subsets of some universal set, their intersection graph is defined as the graph with one vertex for each set and two vertices are adjacent precisely when their representing sets have non-empty intersection. Sometimes…

General Mathematics · Mathematics 2016-02-15 Mahipal Jadeja , Rahul Muthu , Sunitha V

In this paper we consider $j$-tuple-connected components in random $k$-uniform hypergraphs (the $j$-tuple-connectedness relation can be defined by letting two $j$-sets be connected if they lie in a common edge and consider the transitive…

Combinatorics · Mathematics 2014-12-22 Oliver Cooley , Mihyun Kang , Yury Person

A contraction sequence of a graph consists of iteratively merging two of its vertices until only one vertex remains. The recently introduced twin-width graph invariant is based on contraction sequences. More precisely, if one puts red edges…

Data Structures and Algorithms · Computer Science 2022-06-02 Édouard Bonnet , Eun Jung Kim , Amadeus Reinald , Stéphan Thomassé

Given a connected graph $G$, the metric (resp. edge metric) dimension of $G$ is the cardinality of the smallest ordered set of vertices that uniquely identifies every pair of distinct vertices (resp. edges) of $G$ by means of distance…

Combinatorics · Mathematics 2020-06-23 Martin Knor , Snjezana Majstorovic , Aoden Teo Masa Toshi , Riste Skrekovski , Ismael G. Yero

For each positive integer $n$, we define the divisibility relation graph $D_n$ whose vertex set is the set of divisors of $n$, and in which two vertices are adjacent if one is a divisor of the other. This type of graph is a special case of…

Combinatorics · Mathematics 2025-07-10 Jonathan L. Merzel , Ján Mináč , Tung T. Nguyen , Nguyen Duy Tân

We study set systems formed by neighborhoods in graphs of bounded twin-width. We start by proving that such graphs have linear neighborhood complexity, in analogy to previous results concerning graphs from classes with bounded expansion and…

Logic in Computer Science · Computer Science 2023-04-27 Wojciech Przybyszewski

Let $W(G)$ be the Wiener index of a graph $G$. We say that a vertex $v \in V(G)$ is a \v{S}olt\'es vertex in $G$ if $W(G - v) = W(G)$, i.e. the Wiener index does not change if the vertex $v$ is removed. In 1991, \v{S}olt\'es posed the…

Combinatorics · Mathematics 2024-06-05 Nino Bašić , Martin Knor , Riste Škrekovski

Let $\delta$ and $\Delta$ be the minimum and the maximum degree of the vertices of a simple connected graph $G$, respectively. The distinguishing index of a graph $G$, denoted by $D'(G)$, is the least number of labels in an edge labeling of…

Combinatorics · Mathematics 2017-05-17 Saeid Alikhani , Samaneh Soltani

A $(2,1)$-total labeling of a graph $G$ is an assignment $f$ from the vertex set $V(G)$ and the edge set $E(G)$ to the set $\{0,1,...,k\}$ of nonnegative integers such that $|f(x)-f(y)|\ge 2$ if $x$ is a vertex and $y$ is an edge incident…

Discrete Mathematics · Computer Science 2009-11-25 Toru Hasunuma , Toshimasa Ishii , Hirotaka Ono , Yushi Uno

Given a finite point set P in general position in the plane, a full triangulation is a maximal straight-line embedded plane graph on P. A partial triangulation is a full triangulation of some subset P' of P containing all extreme points in…

Computational Geometry · Computer Science 2020-08-17 Uli Wagner , Emo Welzl

A distance oracle (DO) with stretch $(\alpha, \beta)$ for a graph $G$ is a data structure that, when queried with vertices $s$ and $t$, returns a value $\widehat{d}(s,t)$ such that $d(s,t) \le \widehat{d}(s,t) \le \alpha \cdot d(s,t) +…

Data Structures and Algorithms · Computer Science 2024-08-21 Davide Bilò , Shiri Chechik , Keerti Choudhary , Sarel Cohen , Tobias Friedrich , Martin Schirneck

In this paper, a new graph structure called the \textit{coprime order graph} of a finite group $G$ denoted by $\Theta(G)$ has been introduced. The \textit{coprime graph} of a finite group introduced by Ma, Wei, and Yang [\textit{The coprime…

Combinatorics · Mathematics 2021-11-24 Subarsha Banerjee

A complex unit gain graph (or a $\mathbb{T}$-gain graph) $\Theta(\Sigma,\varphi)$ is a graph where the unit complex number is assign by a function $\varphi$ to every oriented edge of $\Sigma$ and assign its inverse to the opposite…

Combinatorics · Mathematics 2024-04-29 Suliman Khan

The degree distribution of a graph $G=(V,E)$, $|V|=n$, $|E|=m$ is one of the most fundamental objects of study in the analysis of graphs as it embodies relationship among entities. In particular, an important derived distribution from…

Data Structures and Algorithms · Computer Science 2025-07-30 Arijit Bishnu , Debarshi Chanda , Gopinath Mishra

We provide first a categorical exploration of, and then completion of the mapping of the relationships among, three fundamental perspectives on binary relations: as the incidence matrices of hypergraphs, as the formal contexts of concept…

Combinatorics · Mathematics 2025-04-22 Robert E. Green , Cliff A. Joslyn , Audun Myers , Michael G. Rawson , Michael Robinson

Using a result of Vdovina, we may associate to each complete connected bipartite graph $\kappa$ a $2$-dimensional square complex, which we call a tile complex, whose link at each vertex is $\kappa$. We regard the tile complex in two…

Combinatorics · Mathematics 2021-02-18 S. A. Mutter

We deal in this work with a class of graphs, namely, the class of distance-regular graphs, in which on the basis of $k$-adjacency operators, the adjacency operator $A$ of a distance-regular graph is identified as a Jacobi matrix. To get so,…

Mathematical Physics · Physics 2024-05-17 Josué I. Rios-Cangas
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