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We are concerned with orderable groups and particularly those with orderings invariant not only under multiplication, but also under a given automorphism or family of automorphisms. Several applications to topology are given: we prove that…

Group Theory · Mathematics 2014-10-01 Dale Rolfsen , Bert Wiest

We establish a general criterion for the finite presentability of subdirect products of groups and use this to characterize finitely presented residually free groups. We prove that, for all $n\in\mathbb{N}$, a residually free group is of…

Group Theory · Mathematics 2008-09-23 Martin R. Bridson , James Howie , Charles F. Miller , Hamish Short

An automorphism of a group is said to be normal if it preserves each normal subgroup. In this paper, we determine the normal automorphisms of a free metabelian nilpotent group.

Group Theory · Mathematics 2007-11-19 G. Endimioni

The notion of positive-definite functions over locally compact quantum groups was recently introduced and studied by Daws and Salmi. Based on this work, we generalize various well-known results about positive-definite functions over groups…

Operator Algebras · Mathematics 2019-08-15 Volker Runde , Ami Viselter

We provide a treatment of isomorphism within a set-theoretic formulation of dependent type theory. Type expressions are assigned their natural set-theoretic compositional meaning. Types are divided into small and large types --- sets and…

Logic in Computer Science · Computer Science 2018-01-23 David McAllester

The isomorphism problem for infinite finitely presented groups is probably the hardest among standard algorithmic problems in group theory. Classes of groups where it has been completely solved are nilpotent groups, hyperbolic groups, and…

Group Theory · Mathematics 2025-06-18 Vladimir Shpilrain

The goal of this work is to develop, in a systematic way and in a full natural generality, the foundations of a theory of functions of (free) noncommuting variables.

Operator Algebras · Mathematics 2014-07-28 Dmitry S. Kaliuzhnyi-Verbovetskyi , Victor Vinnikov

A concrete family of automorphisms alpha_n of the free group F_n is exhibited, for any n > 2, and the following properties are proved: alpha_n is irreducible with irreducible powers, has trivial fixed subgroup, and has 2n-1 attractive as…

Group Theory · Mathematics 2009-04-10 Andre Jaeger , Martin Lustig

We describe the groups of inner and outer automorphisms of the free metabelian nilpotent Lie algebra of finite rank over a field of characteristic 0. To obtain this result we first describe the groups of inner and continuous outer…

Rings and Algebras · Mathematics 2010-03-02 Vesselin Drensky , Sehmus Findik

We study so called weakly-periodic twisted-multiplicative automorphisms of the free skew-field. In particular, we show that any automorphism of a free skew-field that is defined by a periodic automorphism of a free group is equivalent to a…

Group Theory · Mathematics 2023-04-18 Gregor Podlogar

Using the theory of group action, we first introduce the concept of the automorphism group of an exponential family or a graphical model, thus formalizing the general notion of symmetry of a probabilistic model. This automorphism group…

Artificial Intelligence · Computer Science 2012-07-24 Hung Hai Bui , Tuyen N. Huynh , Sebastian Riedel

We describe a set of defining relations for automorphism groups of finitely generated free algebras of Nielsen-Schreier varieties. In particular, this gives a representation of the automorphism groups of free Lie algebras by generators and…

Rings and Algebras · Mathematics 2020-01-03 Ualbai Umirbaev

The group of 2-by-2 matrices with integer entries and determinant $\pm > 1$ can be identified either with the group of outer automorphisms of a rank two free group or with the group of isotopy classes of homeomorphisms of a 2-dimensional…

Group Theory · Mathematics 2007-05-23 Martin R Bridson , Karen Vogtmann

This survey on the automorphism groups of finite p-groups focuses on three major topics: explicit computations for familiar finite p-groups, such as the extraspecial p-groups and Sylow p-subgroups of Chevalley groups; constructing p-groups…

Group Theory · Mathematics 2007-05-23 Geir T. Helleloid

In this paper, we mainly discuss some generalized metric properties and the character of the free paratopological groups, and extend several results valid for free topological groups to free paratopological groups.

General Topology · Mathematics 2013-02-19 Fucai Lin

The automorphism group of a one dimensional shift space over a finite alphabet exhibits different types of behavior: for a large class with positive entropy, it contains a rich collection of subgroups, while for many shifts of zero entropy,…

Dynamical Systems · Mathematics 2017-08-11 Van Cyr , John Franks , Bryna Kra

In this note, we consider models in $\mathbb C^2$. The purpose of this note is twofold. We first show a characterization of models in $\mathbb C^2$ by their noncompact automorphism groups. Then we give an explicit description for…

Complex Variables · Mathematics 2014-10-09 Ninh Van Thu , Mai Anh Duc

The relation between representations and positive definite functions is a key concept in harmonic analysis on topological groups. Recently this relation has been studied on topological groupoids. This is the first in a series of papers in…

Operator Algebras · Mathematics 2007-05-23 Massoud Amini , Alireza Medghalchi

We study the automorphisms group action on a bounded domain in $\CC^n$ having a boundary point that is exponentially flat. Such a domain typically has a compact automorphism group. Our results enable us to generate many new examples.

Complex Variables · Mathematics 2010-10-08 Steven G. Krantz

This paper presents rules of inference for a binary quantifier $I$ for the formalisation of sentences containing definite descriptions within intuitionist positive free logic. $I$ binds one variable and forms a formula from two formulas.…

Logic in Computer Science · Computer Science 2021-08-12 Nils Kürbis