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Related papers: Cayley automatic groups are not Cayley biautomatic

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The finiteness problem for automaton groups and semigroups has been widely studied, several partial positive results are known. However we prove that, in the most general case, the problem is undecidable. We study the case of automaton…

Formal Languages and Automata Theory · Computer Science 2014-03-21 Pierre Gillibert

In this work we characterise Cayley graphs of Coxeter groups with respect to the standard generating set that admit uncountable vertex stabilisers. As a corollary, we fully identify finitely generated Coxeter groups for which the…

Group Theory · Mathematics 2023-02-10 Federico Berlai , Michal Ferov

We prove that the word problem is undecidable in functionally recursive groups, and that the order problem is undecidable in automata groups, even under the assumption that they are contracting.

Group Theory · Mathematics 2017-11-28 Laurent Bartholdi , Ivan Mitrofanov

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

We investigate Cayley graphs of graph products by showing that graph products with vertex groups that have isomorphic Cayley graphs yield isomorphic Cayley graphs.

Group Theory · Mathematics 2025-03-20 Marjory Mwanza

A Cayley graph on a group $G$ has a natural edge-colouring. We say that such a graph is CCA if every automorphism of the graph that preserves this edge-colouring is an element of the normaliser of the regular representation of $G$. A group…

Combinatorics · Mathematics 2017-04-06 Luke Morgan , Joy Morris , Gabriel Verret

We study the automorphisms of a Cayley graph that preserve its natural edge-colouring. More precisely, we are interested in groups G, such that every such automorphism of every connected Cayley graph on G has a very simple form: the…

Combinatorics · Mathematics 2015-03-27 Ademir Hujdurović , Klavdija Kutnar , Dave Witte Morris , Joy Morris

In this paper we are interested in the asymptotic enumeration of bipartite Cayley digraphs and Cayley graphs over abelian groups. Let $A$ be an abelian group and let $\iota$ be the automorphism of $A$ defined by $a^\iota=a^{-1}$, for every…

Combinatorics · Mathematics 2020-01-16 Jia-Li Du , Yan-Quan Feng , Pablo Spiga

We prove that topologically isomorphic linear cellular automaton shifts are algebraically isomorphic. Using this, we show that two distinct such shifts cannot be isomorphic. We conclude that the automorphism group of a linear cellular…

Dynamical Systems · Mathematics 2018-05-24 Robert Fokkink , Reem Yassawi

We consider the two generalizations of lamplighter groups: automata groups generated by Cayley machine and cross-wired lamplighter groups. For a finite step two nilpotent group with central squares, we study its associated Cayley machine…

Group Theory · Mathematics 2015-11-10 Ning Yang

We prove that fundamental groups of non-orientable 3-manifolds have a solvable conjugacy problem, and construct an algorithm. Together with our earlier work on the conjugacy problem in groups on orientable geometrizable 3-manifolds, all…

Group Theory · Mathematics 2013-08-14 Jean-Philippe Préaux

In this paper, we construct an implementable algorithm which solves the conjugacy problem in twisted right-angled Artin groups (T-RAAGs). In certain cases, the complexity is known to be linear, by reducing the problem to the twisted…

Group Theory · Mathematics 2025-09-25 Gemma Crowe , Islam Foniqi

We show that almost all circulant graphs have automorphism groups as small as possible. Of the circulant graphs that do not have automorphism group as small as possible, we give some families of integers such that it is not true that almost…

Combinatorics · Mathematics 2012-03-06 Soumya Bhoumik , Edward Dobson , Joy Morris

We consider pairs of finitely presented, residually finite groups $P\hookrightarrow\G$ for which the induced map of profinite completions $\hat P\to \hat\G$ is an isomorphism. We prove that there is no algorithm that, given an arbitrary…

Group Theory · Mathematics 2008-10-03 Martin R. Bridson

We obtain an explicit description of the endomorphisms of free-abelian by free groups together with a characterization of when they are injective and surjective. As a consequence we see that free-abelian by free groups are Hopfian and not…

Group Theory · Mathematics 2024-01-17 André Carvalho , Jordi Delgado

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

A number of authors have studied the question of when a graph can be represented as a Cayley graph on more than one nonisomorphic group. The work to date has focussed on a few special situations: when the groups are $p$-groups; when the…

Combinatorics · Mathematics 2020-05-26 Joy Morris , Josip Smolcic

We show that the isomorphism problem is solvable in the class of central extensions of word-hyperbolic groups, and that the isomorphism problem for biautomatic groups reduces to that for biautomatic groups with finite centre. We describe an…

Geometric Topology · Mathematics 2015-05-27 Martin R. Bridson , Lawrence Reeves

We prove that the isomorphism of scattered tree automatic linear orders as well as the existence of automorphisms of scattered word automatic linear orders are undecidable. For the existence of automatic automorphisms of word automatic…

Logic in Computer Science · Computer Science 2012-04-26 Dietrich Kuske

We propose a new generalisation of Cayley automatic groups, varying the time complexity of computing multiplication, and language complexity of the normal form representatives. We first consider groups which have normal form language in the…

Group Theory · Mathematics 2021-08-18 Dmitry Berdinsky , Murray Elder , Prohrak Kruengthomya