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The isomorphism problem for digraphs is a fundamental problem in graph theory. This problem for Cayley digraphs has been extensively investigated over the last half a century. In this paper, we consider this problem for $m$-Cayley digraphs…

Combinatorics · Mathematics 2024-09-04 Xing Zhang , Yuan-Quan Feng , Fu-Gang Yin , Jin-Xin Zhou

Characterizations graphs of some classes to induce periodic Grover walks have been studied for recent years. In particular, for the strongly regular graphs, it has been known that there are only three kinds of such graphs. Here, we focus on…

Combinatorics · Mathematics 2018-05-22 Yusuke Yoshie

We consider isomorphism of controllable graphs and cospectrality of distance-regularized graphs (which are known to be distance-regular or distance-biregular) in relation to logical definability. While most characterizations of these…

Combinatorics · Mathematics 2026-03-05 Aida Abiad , Anuj Dawar , Octavio B. Zapata-Fonseca

From the point of view of discrete geometry, the class of locally finite transitive graphs is a wide and important one. The subclass of Cayley graphs is of particular interest, as testifies the development of geometric group theory. Recall…

Combinatorics · Mathematics 2016-12-06 Sébastien Martineau

In this paper, we show that every bipartite distance-regular Cayley graph with diameter $3$ can be constructed on the semidirect product of a group and $\mathbb{Z}_{2}$, except possibly for one case.

Combinatorics · Mathematics 2021-09-29 Mojtaba Jazaeri

We consider the degree-diameter problem for Cayley graphs of dihedral groups. We find upper and lower bounds on the maximum number of vertices of such a graph with diameter 2 and degree $d$. We completely determine the asymptotic behaviour…

Combinatorics · Mathematics 2015-02-17 Grahame Erskine

In this paper, we give constructions of strongly regular Cayley graphs and skew Hadamard difference sets. Both constructions are based on choosing cyclotomic classes in finite fields, and our results generalize ten of the eleven sporadic…

Combinatorics · Mathematics 2012-03-01 Koji Momihara

For non-negative integers~$k$, we consider graphs in which every vertex has exactly $k$ vertices at distance~$2$, i.e., graphs whose distance-$2$ graphs are $k$-regular. We call such graphs $k$-metamour-regular motivated by the terminology…

Combinatorics · Mathematics 2022-12-20 Elisabeth Gaar , Daniel Krenn

A digraph is semicomplete if any two vertices are connected by at least one arc and is locally semicomplete if the out-neighbourhood (resp. in-neighbourhood) of any vertex induces a semicomplete digraph. In this paper, we characterize all…

Combinatorics · Mathematics 2024-09-12 Yuefeng Yang , Shuang Li , Kaishun Wang

Mirror graphs were introduced by Bre\v{s}ar et al. in 2004 as an intriguing class of graphs: vertex-transitive, isometrically embeddable into hypercubes, having a strong connection with regular maps and polytope structure. In this article…

Combinatorics · Mathematics 2016-09-05 Tilen Marc

An automorphism of a graph is called quasi-semiregular if it fixes a unique vertex of the graph and its remaining cycles have the same length. This kind of symmetry of graphs was first investigated by Kutnar, Malni\v{c}, Mart\'{i}nez and…

Combinatorics · Mathematics 2021-08-02 Fu-Gang Yin , Yan-Quan Feng , Jin-Xin Zhou , A-Hui Jia

Weakly distance-regular digraphs are a natural directed version of distance-regular graphs. In [16], we classified all commutative weakly distance-regular digraphs whose underlying graphs are Hamming graphs, folded n-cubes, or Doob graphs.…

Combinatorics · Mathematics 2024-08-07 Qing Zeng , Yuefeng Yang , Kaishun Wang

A non-complete geometric distance-regular graph is the point graph of a partial geometry in which the set of lines is a set of Delsarte cliques. In this paper, we prove that for fixed integer $m\geq 2$, there are only finitely many…

Combinatorics · Mathematics 2009-08-17 J. H. Koolen , S. Bang

A graph $\G$ with a group $H$ of automorphisms acting semiregularly on the vertices with two orbits is called a {\em bi-Cayley graph} over $H$. When $H$ is a normal subgroup of $\Aut(\G)$, we say that $\G$ is {\em normal} with respect to…

Combinatorics · Mathematics 2016-07-15 Jin-Xin Zhou

The diameter of a graph measures the maximal distance between any pair of vertices. The diameters of many small-world networks, as well as a variety of other random graph models, grow logarithmically in the number of nodes. In contrast, the…

Combinatorics · Mathematics 2011-04-05 Jens Marklof , Andreas Strömbergsson

We present simple graph-theoretic characterizations of Cayley graphs for monoids, semigroups and groups. We extend these characterizations to commutative monoids, semilattices, and abelian groups.

Discrete Mathematics · Computer Science 2019-03-18 Didier Caucal

In this note, we provide several constructions of Deza Cayley graphs over groups having a generalized dihedral subgroup. These constructions are based on a usage of (relative) difference sets.

Combinatorics · Mathematics 2026-01-15 Grigory Ryabov

A few properties of unitary Cayley graphs are explored using their eigenvalues. It is shown that the adjacency algebra of a unitary Cayley graph is a coherent algebra. Finally, a class of unitary Cayley graphs that are distance regular are…

Number Theory · Mathematics 2017-07-11 A. Satyanarayana Reddy

The relative Cayley graph of a group $G$ with respect to its proper subgroup $H$, is a graph whose vertices are elements of $G$ and two vertices $h\in H$ and $g\in G$ are adjacent if $g=hc$ for some $c\in C$, where $C$ is an inversed-closed…

Combinatorics · Mathematics 2015-10-14 Mohammad Farrokhi Derakhshandeh Ghouchan , Mehdi Rajabian , Ahmad Erfanian

In this paper,we construct some directed strongly regular Cayley graphs on dihedral groups,these generalizes some earlier constructions.We also characterize some certain directed strongly regular Cayley graphs on dihedral groups…

Combinatorics · Mathematics 2019-09-20 Yiqin He , Bicheng Zhang , Rongquan Feng