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We obtain a complete classification of graph products of finite abelian groups whose Cayley graphs with respect to the standard presentations are planar.

Group Theory · Mathematics 2019-02-28 Olga Varghese

A discrete analog of quantum unique ergodicity was proved for Cayley graphs of quasirandom groups by Magee, Thomas and Zhao. They show that for large graphs there exist real orthonormal basis of eigenfunctions of the adjacency matrix such…

Mathematical Physics · Physics 2024-12-24 Jon Harrison , Clare Pruss

Ne\v{s}et\v{r}il and \v{S}\'{a}mal asked whether every cubelike graph has a cubelike core. Man\v{c}inska, Pivotto, Roberson and Royle answered this question in the affirmative for cubelike graphs whose core has at most $32$ vertices. When…

Combinatorics · Mathematics 2025-01-31 Guang Rao , Colin Tan

The standard double cover of a graph $\Gamma$ is the direct product $\Gamma\times K_2$. A graph $\Gamma$ is said to be stable if all the automorphisms of $\Gamma\times K_2$ come from its factors. Although the study of stability has…

Combinatorics · Mathematics 2026-01-29 Binzhou Xia , Zhishuo Zhang , Shasha Zheng

A graph $\Gamma$ is a bi-Cayley graph over a group $G$ if $G$ is a semiregular group of automorphisms of $\Gamma$ having two orbits. Let $G$ be a non-abelian metacyclic $p$-group for an odd prime $p$, and let $\Gamma$ be a connected…

Combinatorics · Mathematics 2017-07-11 Yi Wang , Yan-Quan Feng

In this paper, firstly, we provide some necessary and sufficient conditions for generalized Cayley graphs on abelian groups to be bipartite. Secondly, we deduce several necessary and sufficient conditions for generalized Cayley graphs on…

Combinatorics · Mathematics 2024-12-18 Liao Qianfen , Liu Weijun , Zhang Pengli

We introduce a notion of Ricci curvature for Cayley graphs that can be thought of as "medium-scale" because it is neither infinitesimal nor asymptotic, but based on a chosen finite radius parameter. We argue that it gives the foundation for…

Group Theory · Mathematics 2020-07-06 Assaf Bar-Natan , Moon Duchin , Robert Kropholler

We show that the cop number of the Cayley sum graph of a finite group $G$ with respect to a symmetric subset $S$ is at most twice its degree when the graph is connected, undirected. We also prove that a similar bound holds for the cop…

Combinatorics · Mathematics 2025-04-29 Arindam Biswas , Jyoti Prakash Saha

Given a finite group $\Gamma$, a regular $t$-balanced Cayley map (RBCM$_{t}$ for short) is a regular Cayley map $\mathcal{CM}(G,\Omega,\rho)$ such that $\rho(\omega)^{-1}=\rho^{t}(\omega)$ for all $\omega\in\Omega$. In this paper, we…

Combinatorics · Mathematics 2024-02-27 Haimiao Chen

We derive a number of upper and lower bounds for the first nontrivial eigenvalue of a finite quantum graph in terms of the edge connectivity of the graph, i.e., the minimal number of edges which need to be removed to make the graph…

Spectral Theory · Mathematics 2019-06-04 Gregory Berkolaiko , James B. Kennedy , Pavel Kurasov , Delio Mugnolo

We prove that any finite abelian group $G$ contains a collection of not too many subsets with a special structure, so that for every subset $A$ of $G$ with a small doubling, there is a member $F$ of the collection that is fully contained in…

Combinatorics · Mathematics 2025-09-03 Noga Alon , Huy Tuan Pham

The theory of Frobenius groups with Frobenius complements of even order largely reduces to tractable algebraic number theory. If we consider only Frobenius complements with an upper bound $s$ on the number of distinct primes dividing the…

Group Theory · Mathematics 2021-02-09 Ron Brown

In this paper, we investigate the existence of fractional revival on Cayley graphs over finite abelian groups. We give a necessary and sufficient condition for Cayley graphs over finite abelian groups to have fractional revival. As…

Combinatorics · Mathematics 2024-01-17 Jing Wang , Ligong Wang , Xiaogang Liu

We construct an infinite family of bounded-degree bipartite unique-neighbour expander graphs with arbitrarily unbalanced sides. Although weaker than the lossless expanders constructed by Capalbo et al., our construction is simpler and may…

Combinatorics · Mathematics 2023-01-10 Ron Asherov , Irit Dinur

In this paper, we investigate the existence of fractional revival on semi-Cayley graphs over finite abelian groups. We give some necessary and sufficient conditions for semi-Cayley graphs over finite abelian groups admitting fractional…

Combinatorics · Mathematics 2023-08-07 Jing Wang , Ligong Wang , Xiaogang Liu

A Cayley graph of a group $H$ is a finite simple graph $\Gamma$ such that its automorphism group ${\rm Aut}(\Gamma)$ contains a subgroup isomorphic to $H$ acting regularly on $V(\Gamma)$, while a Haar graph of $H$ is a finite simple…

Combinatorics · Mathematics 2019-08-14 Yan-Quan Feng , István Kovács , Jie Wang , Da-Wei Yang

This paper establishes connections between the structure of a semigroup and the minimum spans of distance labellings of its Cayley graphs. We show that certain general restrictions on the minimum spans are equivalent to the semigroup being…

Combinatorics · Mathematics 2015-09-04 Andrei Kelarev , Charl Ras , Sanming Zhou

A Cayley graph of a group $H$ is a finite simple graph $\Gamma$ such that ${\rm Aut}(\Gamma)$ contains a subgroup isomorphic to $H$ acting regularly on $V(\Gamma)$, while a Haar graph of $H$ is a finite simple bipartite graph $\Sigma$ such…

Combinatorics · Mathematics 2017-07-12 Yan-Quan Feng , Istvan Kovacs , Da-Wei Yang

Does every $n$-vertex Cayley graph have an orthonormal eigenbasis all of whose coordinates are $O(1/\sqrt{n})$? While the answer is yes for abelian groups, we show that it is no in general. On the other hand, we show that every $n$-vertex…

Combinatorics · Mathematics 2020-10-29 Ashwin Sah , Mehtaab Sawhney , Yufei Zhao

Given an integer $D$ and an ordinary isogeny class of abelian varieties defined over a finite field $\mathbb{F}_q$ with commutative $\mathbb{F}_q$-endomorphism algebra, we provide algorithms for computing all isogenies of degree dividing…

Number Theory · Mathematics 2026-01-30 Edgar Costa , Taylor Dupuy , Stefano Marseglia , David Roe , Christelle Vincent
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