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Related papers: The Diophantine problem in Thompson's group F

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We survey solvability of equations in wreath products of groups, and prove that the quadratic diophantine problem is solvable in wreath products of Abelian groups. We consider the related question of determining commutator width, and prove…

Group Theory · Mathematics 2024-10-08 Laurent Bartholdi , Ruiwen Dong , Leon Pernak , Jan Philipp Wächter

We prove that Thompson's group $F$ has a subgroup $H$ such that the conjugacy problem in $H$ is undecidable and the membership problem in $H$ is easily decidable. The subgroup $H$ of $F$ is a closed subgroup of $F$. That is, every function…

Group Theory · Mathematics 2021-05-04 Gili Golan , Mark Sapir

We show that the generation problem in Thompson group $F$ is decidable, i.e., there is an algorithm which decides if a finite set of elements of $F$ generates the whole $F$. The algorithm makes use of the Stallings $2$-core of subgroups of…

Group Theory · Mathematics 2021-05-04 Gili Golan

We study one-variable equations over the lamplighter group $\MZ_2 \wr \MZ$. While the decidability of arbitrary equations over $L_2$ remains open, we prove that the Diophantine problem for single equations in one variable is decidable. Our…

Group Theory · Mathematics 2026-01-21 Alexander Ushakov , Yankun Wang

In this paper we show that membership in finitely generated submonoids is undecidable for the free metabelian group of rank 2 and for the wreath product $\mathbb Z\wr (\mathbb Z\times \mathbb Z)$. We also show that subsemimodule membership…

Group Theory · Mathematics 2009-03-05 Markus Lohrey , Benjamin Steinberg

In this paper we consider the palindromic width of free nilpotent groups. In particular, we prove that the palindromic width of a finitely generated free nilpotent group is finite. We also prove that the palindromic width of a free…

Group Theory · Mathematics 2014-02-25 Valeriy G. Bardakov , Krishnendu Gongopadhyay

We introduce the subgroup identification problem, and show that there is a finitely presented group G for which it is unsolvable, and that it is uniformly solvable in the class of finitely presented locally Hopfian groups. This is done as…

Group Theory · Mathematics 2016-10-20 Maurice Chiodo

A celebrated result of J. Thompson says that if a finite group $G$ has a fixed-point-free automorphism of prime order, then $G$ is nilpotent. The main purpose of this note is to extend this result to finite inverse semigroups. An earlier…

Group Theory · Mathematics 2013-11-07 Joao Araujo , Michael Kinyon

Let $k \geq 2$, $q$ be an odd prime power, and $F \in \mathbb{F}_q[x_1, \ldots, x_k]$ be a polynomial. An $F$-Diophantine set over a finite field $\mathbb{F}_q$ is a set $A \subset \mathbb{F}_q^*$ such that $F(a_1, a_2, \ldots, a_k)$ is a…

Number Theory · Mathematics 2025-05-09 Chi Hoi Yip , Semin Yoo

We show the existence of finitely presented torsion-free groups with decidable word problem that cannot be embedded in any finitely generated group with decidable conjugacy problem. This answers a well-known question of Collins from the…

Group Theory · Mathematics 2019-12-02 Arman Darbinyan

We prove sharp estimates in a shrinking target problem for the action of an arbitrary subgroup $\Gamma$ of $SL_2(\mathbb{Z})$ on the 2-torus. This can also be viewed as a non-commutative Diophantine approximation problem. The methods…

Dynamical Systems · Mathematics 2016-07-21 Vladimir Finkelshtein

We prove that a permutation group in which different finite sets have different stabilizers cannot satisfy any group law. For locally compact topological groups with this property we show that almost all finite subsets of the group generate…

Group Theory · Mathematics 2007-05-23 Miklos Abert

Golan and Sapir \cite{MR3978542} proved that the Thompson's groups $F$, $T$ and $V$ have linear divergence. In the current paper, we focus on the divergence properties of several generalisation of the Thompson's groups, we first consider…

Group Theory · Mathematics 2022-09-27 Xiaobing Sheng

We prove that the isomorphism problem for finitely generated fully residually free groups is decidable. We also show that each finitely generated fully residually free group G has a decomposition that is invariant under automorphisms of G,…

Group Theory · Mathematics 2007-05-23 Inna Bumagin , Olga Kharlampovich , Alexei Miasnikov

Pursueing our investigations on the relations between Thompson groups and mapping class groups, we introduce the group $T^*$ (and its further generalizations) which is an extension of the Ptolemy-Thompson group $T$ by means of the full…

Geometric Topology · Mathematics 2014-11-11 Louis Funar , Christophe Kapoudjian

We prove that the autonomous norm on the group of Hamiltonian diffeomorphisms of the two-dimensional torus is unbounded. We provide explicit examples of Hamiltonian diffeomorphisms with arbitrarily large autonomous norm. For the proofs we…

Symplectic Geometry · Mathematics 2016-02-16 Michael Brandenbursky , Jarek Kedra , Egor Shelukhin

We show that the compressed word problem in a finitely-generated fully residually free group (F -group) is decidable in polynomial time, and use the result to show that the word problem in the automorphism group of such a group is decidable…

Group Theory · Mathematics 2009-10-21 Jeremy Macdonald

We show that the universal theory of torsion groups is strongly contained in the universal theory of finite groups. This answers a question of Dyson. We also prove that the universal theory of some natural classes of torsion groups is…

Group Theory · Mathematics 2009-03-26 D. Osin

We deal with the problem of existence of uncountable co-Hopfian abelian groups and (absolute) Hopfian abelian groups. Firstly, we prove that there are no co-Hopfian reduced abelian groups $G$ of size $< \mathfrak{p}$ with infinite…

Group Theory · Mathematics 2025-07-10 Gianluca Paolini , Saharon Shelah

We prove irreducibility and mutual inequivalence for certain unitary representations of R. Thompson's groups F and T.

Operator Algebras · Mathematics 2019-06-25 Vaughan F. R. Jones