Classification of finite groups that admit an oriented regular representation

J Morris, P Spiga - Bulletin of the London Mathematical Society, 2018 - Wiley Online Library
This is the third, and last, of a series of papers dealing with oriented regular representations.
Here we complete the classification of finite groups that admit an oriented regular …

Graphical frobenius representations

JK Doyle, TW Tucker, ME Watkins - Journal of Algebraic Combinatorics, 2018 - Springer
A Frobenius group is a transitive permutation group that is not regular and such that only the
identity fixes more than one point. A graphical Frobenius representation (GFR) of a …

On the existence of Frobenius digraphical representations

P Spiga - The Electronic Journal of Combinatorics, 2018 - combinatorics.org
A Frobenius group is a transitive permutation group that is not regular and such that only the
identity fixes more than one point. A digraphical, respectively graphical, Frobenius …

Haar graphical representations of finite groups and an application to poset representations

J Morris, P Spiga - arXiv preprint arXiv:2404.12658, 2024 - arxiv.org
Let $ R $ be a group and let $ S $ be a subset of $ R $. The Haar graph $\mathrm {Haar}(R,
S) $ of $ R $ with connection set $ S $ is the graph having vertex set $ R\times\{-1, 1\} …

[HTML][HTML] On the existence of graphical Frobenius representations and their asymptotic enumeration

P Spiga - Journal of Combinatorial Theory, Series B, 2020 - Elsevier
We give a complete answer to the GFR conjecture, proposed by Conder, Doyle, Tucker and
Watkins:“All but finitely many Frobenius groups F= N⋊ H with a given complement H have a …

[HTML][HTML] Finite groups admitting an oriented regular representation

P Spiga - Journal of Combinatorial Theory, Series A, 2018 - Elsevier
In this paper, we investigate finite groups admitting an oriented regular representation and
we give a partial answer to a 1980 question of Lazslo Babai:“Which [finite] groups admit an …

On normality of n-Cayley graphs

A Hujdurović, K Kutnar, D Marušič - Applied Mathematics and Computation, 2018 - Elsevier
Let G be a finite group and X a (di) graph. If there exists a semiregular subgroup G¯ of the
automorphism group Aut (X) isomorphic to G with n orbits on V (X) then the (di) graph X is …

Tetravalent 2-arc-transitive Cayley graphs on non-abelian simple groups

JL Du, YQ Feng - Communications in Algebra, 2019 - Taylor & Francis
Let G be a finite non-abelian simple group and let Γ be a connected tetravalent 2-arc-
transitive G-regular graph. In 2004, Fang, Li, and Xu proved that either G is normal in the full …

[HTML][HTML] A classification of the graphical m-semiregular representation of finite groups

JL Du, YQ Feng, P Spiga - Journal of Combinatorial Theory, Series A, 2020 - Elsevier
In this paper we extend the classical notion of digraphical and graphical regular
representation of a group and we classify, by means of an explicit description, the finite …

Cayley graphs with few automorphisms

PH Leemann, M de La Salle - Journal of Algebraic Combinatorics, 2021 - Springer
We show that every finitely generated group G with an element of order at least\bigl (5\,
rank\,(G)\bigr)^ 12 (5 rank (G)) 12 admits a locally finite directed Cayley graph with …