scholarly journals TWISTED CONJUGACY CLASSES IN WREATH PRODUCTS

2006 ◽  
Vol 16 (05) ◽  
pp. 875-886 ◽  
Author(s):  
DACIBERG GONÇALVES ◽  
PETER WONG

Let G be a finitely generated abelian group and G ≀ ℤ be the wreath product. In this paper, we classify all such groups G for which every automorphism of G ≀ ℤ has infinitely many twisted conjugacy classes.

1973 ◽  
Vol 9 (1) ◽  
pp. 127-136
Author(s):  
Yeo Kok Chye

Let d(G) denote the minimum of the cardinalities of the generating sets of the group G. Call a generating set of cardinality d(G) a minimal generating set for G. If A is a finitely generated nilpotent group, B a non-trivial finitely generated abelian group and A wr B is their (restricted, standard) wreath product, then it is proved (by explicitly constructing a minimal generating set for A wr B ) that d(AwrB) = max{l+d(A), d(A×B)} where A × B is their direct product.


2010 ◽  
Vol 17 (spec01) ◽  
pp. 799-802 ◽  
Author(s):  
Mehri Akhavan-Malayeri

Let W = G ≀ H be the wreath product of G by an n-generator abelian group H. We prove that every element of W′ is a product of at most n+2 commutators, and every element of W2 is a product of at most 3n+4 squares in W. This generalizes our previous result.


2020 ◽  
pp. 1-12 ◽  
Author(s):  
ADRIEN LE BOUDEC

We consider the finitely generated groups acting on a regular tree with almost prescribed local action. We show that these groups embed as cocompact irreducible lattices in some locally compact wreath products. This provides examples of finitely generated simple groups quasi-isometric to a wreath product $C\wr F$ , where $C$ is a finite group and $F$ a non-abelian free group.


2017 ◽  
Vol 20 (4) ◽  
Author(s):  
Khadijeh Alibabaei

AbstractWe show that the wreath product of a finitely generated abelian group with a polycyclic group is a LERF group. This theorem yields as a corollary that finitely generated free metabelian groups are LERF, a result due to Coulbois. We also show that a free solvable group of class 3 and rank at least 2 does not contain a strictly ascending HNN-extension of a finitely generated group. Since such groups are known not to be LERF, this settles, in the negative, a question of J. O. Button.


Author(s):  
Alexander Fel'shtyn ◽  
Evgenij Troitsky

AbstractThe purpose of the present mostly expository paper (based mainly on [17, 18, 40, 16, 11]) is to present the current state of the following conjecture of A. Fel'shtyn and R. Hill [13], which is a generalization of the classical Burnside theorem.Let G be a countable discrete group, φ one of its automorphisms, R(φ) the number of φ-conjugacy (or twisted conjugacy) classes, and S(φ) = #Fix the number of φ-invariant equivalence classes of irreducible unitary representations. If one of R(φ) and S(φ) is finite, then it is equal to the other.This conjecture plays a important role in the theory of twisted conjugacy classes (see [26], [10]) and has very important consequences in Dynamics, while its proof needs rather sophisticated results from Functional and Noncommutative Harmonic Analysis.First we prove this conjecture for finitely generated groups of type I and discuss its applications.After that we discuss an important example of an automorphism of a type II1 group which disproves the original formulation of the conjecture.Then we prove a version of the conjecture for a wide class of groups, including almost polycyclic groups (in particular, finitely generated groups of polynomial growth). In this formulation the role of an appropriate dual object plays the finite-dimensional part of the unitary dual. Some counter-examples are discussed.Then we begin a discussion of the general case (which also needs new definition of the dual object) and prove the weak twisted Burnside theorem for general countable discrete groups. For this purpose we prove a noncommutative version of Riesz-Markov-Kakutani representation theorem.Finally we explain why the Reidemeister numbers are always infinite for Baumslag-Solitar groups.


2014 ◽  
Vol 57 (2) ◽  
pp. 245-253
Author(s):  
N. Brodskiy ◽  
J. Dydak ◽  
U. Lang

AbstractConsider the wreath product H ≀ G, where H ≠ 1 is finite and G is finitely generated. We show that the Assouad–Nagata dimension dimAN(H ≀ G) of H ≀ G depends on the growth of G as follows: if the growth of G is not bounded by a linear function, then dimAN(H ≀ G) = ∞; otherwise dimAN(H ≀ G) = dimAN(G) ≤ 1.


2006 ◽  
Vol 16 (03) ◽  
pp. 493-503 ◽  
Author(s):  
MARTYN QUICK

We show that the probability of generating an iterated wreath product of non-abelian finite simple groups converges to 1 as the order of the first simple group tends to infinity provided the wreath products are constructed with transitive and faithful actions. This has the consequence that the profinite group which is the inverse limit of these iterated wreath products is positively finitely generated.


2008 ◽  
Vol 18 (02) ◽  
pp. 243-255 ◽  
Author(s):  
PEETER PUUSEMP

Let A be a cyclic group of order pn, where p is a prime, and B be a finite abelian group or a finite p-group which is determined by its endomorphism semigroup in the class of all groups. It is proved that under these assumptions the wreath product A Wr B is determined by its endomorphism semigroup in the class of all groups. It is deduced from this result that if A, B, A0,…, An are finite abelian groups and A0,…, An are p-groups, p prime, then the wreath products A Wr B and An Wr (…( Wr (A1 Wr A0))…) are determined by their endomorphism semigroups in the class of all groups.


2014 ◽  
Vol 91 (2) ◽  
pp. 250-263 ◽  
Author(s):  
CHRIS CAVE ◽  
DENNIS DREESEN

AbstractGiven two finitely generated groups that coarsely embed into a Hilbert space, it is known that their wreath product also embeds coarsely into a Hilbert space. We introduce a wreath product construction for general metric spaces $X,Y,Z$ and derive a condition, called the (${\it\delta}$-polynomial) path lifting property, such that coarse embeddability of $X,Y$ and $Z$ implies coarse embeddability of $X\wr _{Z}Y$. We also give bounds on the compression of $X\wr _{Z}Y$ in terms of ${\it\delta}$ and the compressions of $X,Y$ and $Z$.


2019 ◽  
Vol 22 (2) ◽  
pp. 253-266 ◽  
Author(s):  
Timur Nasybullov

Abstract Let R be an integral domain of characteristic zero. In this note we study the Reidemeister spectrum of the group {{\rm UT}_{n}(R)} of unitriangular matrices over R. We prove that if {R^{+}} is finitely generated and {n>2|R^{*}|} , then {{\rm UT}_{n}(R)} possesses the {R_{\infty}} -property, i.e. the Reidemeister spectrum of {{\rm UT}_{n}(R)} contains only {\infty} , however, if {n\leq|R^{*}|} , then the Reidemeister spectrum of {{\rm UT}_{n}(R)} has nonempty intersection with {\mathbb{N}} . If R is a field and {n\geq 3} , then we prove that the Reidemeister spectrum of {{\rm UT}_{n}(R)} coincides with {\{1,\infty\}} , i.e. in this case {{\rm UT}_{n}(R)} does not possess the {R_{\infty}} -property.


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