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We investigate connected cubic vertex-transitive graphs whose edge sets admit a partition into a $2$-factor $\mathcal{C}$ and a $1$-factor that is invariant under a vertex-transitive subgroup of the automorphism group of the graph and where…

Combinatorics · Mathematics 2026-01-19 Brian Alspach , Primoz Sparl

A graph is vertex-transitive if its automorphism group acts transitively on vertices of the graph. A vertex-transitive graph is a Cayley graph if its automorphism group contains a subgroup acting regularly on its vertices. In this paper,…

Group Theory · Mathematics 2022-03-10 Majid Arezoomand , Mohsen Ghasemi , Mohammad A. Iranmanesh

In 2019, investigation of the so-called factor-invariant cubic graphs was initiated by Alspach, Khodadadpour and Kreher. For a cubic graph $\Gamma$ and a vertex-transitive subgroup $G$ of $\mathrm{Aut}(\Gamma)$, a $2$-factor $\mathcal{C}$…

Combinatorics · Mathematics 2026-01-19 Primož Šparl

It has long been known that there exist finite connected tetravalent arc-transitive graphs with arbitrarily large vertex-stabilisers. However, beside a well known family of exceptional graphs, related to the lexicographic product of a cycle…

Combinatorics · Mathematics 2010-10-14 Primoz Potocnik , Pablo Spiga , Gabriel Verret

We study groups acting vertex-transitively on connected, trivalent graphs such that stabilizers of vertices are infinite. If the action is edge-transitive, we prove that the graph has to be a tree. We analyze the case where the action is…

Combinatorics · Mathematics 2021-01-12 Arnbjörg Soffía Árnadóttir , Waltraud Lederle , Rögnvaldur G. Möller

A finite graph is called a tricirculant if admits a cyclic group of automorphism which has precisely three orbits on the vertex-set of the graph, all of equal size. We classify all finite connected cubic vertex-transitive tricirculants. We…

Combinatorics · Mathematics 2018-12-12 Primož Potočnik , Micael Toledo

The edges surrounding a face of a map $M$ form a cycle $C$, called the boundary cycle of the face, and $C$ is often not a simple cycle. If the map $M$ is arc-transitive, then there is a cyclic subgroup of automorphisms of $M$ which leaves…

Combinatorics · Mathematics 2021-11-05 Jiyong Chen , Cai Heng Li , Cheryl E. Praeger , Shu-Jiao Song

A graph of order $n$ is $p$-factor-critical, where $p$ is an integer of the same parity as $n$, if the removal of any set of $p$ vertices results in a graph with a perfect matching. 1-Factor-critical graphs and 2-factor-critical graphs are…

Combinatorics · Mathematics 2012-12-18 Heping Zhang , Wuyang Sun

A graph is half-arc-transitive if its automorphism group acts transitively on its vertex set, edge set, but not its arc set. In this paper, we study all tetravalent half-arc-transitive graphs of order $12p$.

Combinatorics · Mathematics 2022-06-01 M. Ghasemi , A. A. Talebi , N. Mehdipoor

These notes concern aspects of various graphs whose vertex set is a group $G$ and whose edges reflect group structure in some way (so that they are invariant under the action of the automorphism group of $G$). The graphs I will discuss are…

Group Theory · Mathematics 2021-03-29 Peter J. Cameron

In the mid-1990s, two groups of authors independently obtained classifications of vertex-transitive graphs whose order is a product of two distinct primes. In the intervening years it has become clear that there is additional information…

Combinatorics · Mathematics 2020-03-19 Ted Dobson , Ademir Hujdurović , Klavdija Kutnar , Joy Morris

A graph is edge-transitive if its automorphism group acts transitively on the edge set. In this paper, we investigate the automorphism groups of edge-transitive graphs of odd order and twice prime valency. Let $\Gamma$ be a connected graph…

Combinatorics · Mathematics 2019-10-14 Hong Ci Liao , Jing Jian Li , Zai Ping Lu

A graph is said to be edge-transitive if its automorphism group acts transitively on its edges. It is known that edge-transitive graphs are either vertex-transitive or bipartite. In this paper we present a complete classification of all…

Combinatorics · Mathematics 2019-11-13 Heather A. Newman , Hector Miranda , Darren A. Narayan

A graph is edge-primitive if its automorphism group acts primitively on the edge set. In this short paper, we prove that a finite 2-arc-transitive edge-primitive graph has almost simple automorphism group if it is neither a cycle nor a…

Combinatorics · Mathematics 2019-01-11 Zaiping Lu

The theory of voltage graphs has become a standard tool in the study graphs admitting a semiregular group of automorphisms. We introduce the notion of a cyclic generalised voltage graph to extend the scope of this theory to graphs admitting…

Combinatorics · Mathematics 2020-03-12 Primoz Potocnik , Micael Toledo

In order to complete (and generalize) results of Gardiner and Praeger on 4-valent symmetric graphs (European J. Combin, 15 (1994)) we apply the method of lifting automorphisms in the context of elementary-abelian covering projections. In…

Combinatorics · Mathematics 2017-08-01 Boštjan Kuzman , Aleksander Malnič , Primož Potočnik

A new infinite family of bipartite cubic 3-arc transitive graphs is constructed and studied. They provide the first known examples admitting a 2-arc transitive vertex-biquasiprimitive group of automorphisms for which the index two subgroup…

Group Theory · Mathematics 2011-03-30 Alice Devillers , Michael Giudici , Cai Heng Li , Cheryl E. Praeger

We classify all finite 2-groups that have a cyclic or dihedral maximal subgroup and determine their automorphism groups. Based on this result, we classify all pairs $ (G,\mathcal{M}) $, such that $ G $ is a finite 2-group and $ \mathcal{M}…

Group Theory · Mathematics 2025-08-11 Peice Hua

In this paper, we introduce a family of tetravalent graphs called propeller graphs, denoted by $Pr_{n}(b,c,d)$. We then produce three infinite subfamilies and one finite subfamily of arc-transitive propeller graphs, and show that all such…

Combinatorics · Mathematics 2016-01-05 Matthew C. Sterns

We classify those 2-groups G which factorise as a product of two disjoint cyclic subgroups A and B, transposed by an automorphism of order 2. The case where G is metacyclic having been dealt with elsewhere, we show that for each e>2 there…

Group Theory · Mathematics 2011-12-13 Shaofei Du , Gareth Jones , Jin Ho Kwak , Roman Nedela , Martin Skoviera
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