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This paper deals with the classification of groups $G$ such that power graphs and proper power graphs of $G$ are line graphs. In fact, we classify all finite nilpotent groups whose power graphs are line graphs. Also, we categorize all…

Combinatorics · Mathematics 2022-05-06 Sudip Bera

Chain graphs combine directed and undirected graphs and their underlying mathematics combines properties of the two. This paper gives a simplified definition of chain graphs based on a hierarchical combination of Bayesian (directed) and…

Artificial Intelligence · Computer Science 2013-02-21 Wray L. Buntine

A graph is said to be orthogonalisable if the set of real symmetric matrices whose off-diagonal pattern is prescribed by its edges contains an orthogonal matrix. We determine some necessary and some sufficient conditions on the sizes of the…

Combinatorics · Mathematics 2025-06-16 Rupert H. Levene , Polona Oblak , Helena Šmigoc

A connected linear algebraic group G is called a Cayley group if the Lie algebra of G endowed with the adjoint G-action and the group variety of G endowed with the conjugation G-action are birationally G-isomorphic. In particular, the…

Algebraic Geometry · Mathematics 2009-07-06 Nicole Lemire , Vladimir L. Popov , Zinovy Reichstein

A finite graph $\Gamma$ is called $G$-symmetric if $G$ is a group of automorphisms of $\Gamma$ which is transitive on the set of ordered pairs of adjacent vertices of $\Gamma$. We study a family of symmetric graphs, called the unitary…

Combinatorics · Mathematics 2015-03-25 Massimo Giulietti , Stefano Marcugini , Fernanda Pambianco , Sanming Zhou

Let $S$ be a set of transpositions generating the symmetric group $S_n$. The transposition graph of $S$ is defined to be the graph with vertex set $\{1,\ldots,n\}$, and with vertices $i$ and $j$ being adjacent in $T(S)$ whenever $(i,j) \in…

Combinatorics · Mathematics 2015-11-18 Ashwin Ganesan

For a group $G,$ the generating graph of $G,$ denoted by $\Gamma(G).$ We define $Q_n=\langle x,y: x^{2n}=y^4=1, x^n=y^2,y^{-1}xy=x^{-1}\rangle,$ the dicyclic group of order $4n.$ This paper primarily delves into exploring the graph…

Combinatorics · Mathematics 2026-02-23 Kavita Samant , A. Satyanarayana Reddy

A connected undirected graph is called \emph{geodetic} if for every pair of vertices there is a unique shortest path connecting them. It has been conjectured that for finite groups, the only geodetic Cayley graphs are odd cycles and…

Group Theory · Mathematics 2025-04-03 Murray Elder , Adam Piggott , Florian Stober , Alexander Thumm , Armin Weiß

A Cayley digraph Cay(G,S) of a finite group $G$ with respect to a subset $S$ of $G$ is said to be a CI-digraph if for every Cayley digraph Cay(G,T) isomorphic to Cay(G,S), there exists an automorphism $\sigma$ of $G$ such that $S^\sigma=T$.…

Combinatorics · Mathematics 2024-02-22 Jin-Hua Xie , Yan-Quan Feng , Binzhou Xia

As a vital link between group theory and graph theory, Cayley graphs provide a geometric framework for encoding algebraic structures. This study explores the properties of Cayley graphs derived from cyclic groups whose order is the square…

Combinatorics · Mathematics 2026-04-28 Iqbal Atmaja , Ahmad Erfanian , Yeni Susanti , Muhammad Nurul Huda , Ari Suparwanto

A directed graph is set-homogeneous if, whenever U and V are isomorphic finite subdigraphs, there is an automorphism g of the digraph with U^g=V. Here, extending work of Lachlan on finite homogeneous digraphs, we classify finite…

Combinatorics · Mathematics 2010-11-19 Robert Gray , Dugald Macpherson , Cheryl E. Praeger , Gordon F. Royle

The characterization of distance-regular Cayley graphs originated from the problem of identifying strongly regular Cayley graphs, or equivalently, regular partial difference sets. In this paper, a classification of distance-regular Cayley…

Combinatorics · Mathematics 2022-03-25 Xueyi Huang , Kinkar Chandra Das , Lu Lu

A {\em kernel by properly colored paths} of an arc-colored digraph $D$ is a set $S$ of vertices of $D$ such that (i) no two vertices of $S$ are connected by a properly colored directed path in $D$, and (ii) every vertex outside $S$ can…

Combinatorics · Mathematics 2017-04-28 Yandong Bai , Shinya Fujita , Shenggui Zhang

We say that a group G is a cube group if it is generated by a set S of involutions such that the corresponding Cayley graph Cay(G,S) is isomorphic to a cube. Equivalently, G is a cube group if it acts on a cube such that the action is…

Group Theory · Mathematics 2012-01-13 Colin Hagemeyer , Richard Scott

Let $\Gamma=(V,E)$ be a graph. If all the eigenvalues of the adjacency matrix of the graph $\Gamma$ are integers, then we say that $\Gamma$ is an integral graph. A graph $\Gamma$ is determined by its spectrum if every graph cospectral to it…

Combinatorics · Mathematics 2021-01-22 Jia-Bao Liu , S. Morteza Mirafzal , Ali Zafari

This paper investigates the enumeration of Cayley digraphs, focusing on counting Cayley digraphs on dihedral groups up to CI-isomorphism. By leveraging the Cauchy-Frobenius Lemma and properties of automorphisms, we derive an explicit…

Combinatorics · Mathematics 2025-07-30 Zai Ping Lu , Jia Yin Xie , Jin-Hua Xie

Let $G$ be a group and let $S$ be a generating set of $G$. In this article, we introduce a metric $d_C$ on $G$ with respect to $S$, called the cardinal metric. We then compare geometric structures of $(G, d_C)$ and $(G, d_W)$, where $d_W$…

Metric Geometry · Mathematics 2019-03-22 Teerapong Suksumran

The cycle space of a graph corresponds to the kernel of an incidence matrix. We investigate an analogous subspace for digraphs. In the case of digraphs of graphs, where every edge is replaced by two oppositely directed arcs, we give a…

Combinatorics · Mathematics 2016-09-30 Chris Godsil , Krystal Guo

It is shown that there are groups $\Gamma$ with finite generating sets $S$ such that the adjacency operator of the Cayley graph ${\rm Cay}(\Gamma,S)$ is a disjoint union of $N$ intervals, for arbitrarily large integers $N$.

Combinatorics · Mathematics 2024-02-12 Pierre de la Harpe

Graphs defined over a finite ring are well-studied in the literature. Due to their nature, these types of graphs connect several branches of mathematics, including algebra, number theory, matrix theory, and representation theory. In recent…

Combinatorics · Mathematics 2026-03-24 Tung T. Nguyen , Nguyen Duy Tân