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Related papers: Automorphisms of free groups with boundaries

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Let $F_n$ be the free group on $n\ge 2$ elements and $\A(F_n)$ its group of automorphisms. In this paper we present a rich collection of linear representations of $\A(F_n)$ arising through the action of finite index subgroups of it on…

Group Theory · Mathematics 2007-05-23 Fritz Grunewald , Alexander Lubotzky

Given a variety of universal algebras. A method is suggested for describing automorphisms of a category of free algebras of this variety. Applying this general method all automorphisms of such categories are found in two cases: 1) for the…

Rings and Algebras · Mathematics 2007-05-23 Boris Plotkin , Grigori Zhitomirski

It is known that, for the algebra of functions on a Kleinian singularity, the parameter space of deformations and the parameter space of quantizations coincide. We prove that, for a Kleinian singularity of type $\mathbf{A}$ or $\mathbf{D}$,…

Rings and Algebras · Mathematics 2025-11-10 Simone Castellan

We define two complexes on which the group Aut$(F_n)$ acts freely. The homotopy groups of these are studied. They map to the K-groups of Z and are themselves a sort of pre-K-theory.

K-Theory and Homology · Mathematics 2007-05-23 Jeff Kiralis

This is a biased survey for the Johnson homomorphisms of the automorphism groups of free groups. We just exposit some well known facts and recent developments for the Johnson homomorphisms and its related topics.

Algebraic Topology · Mathematics 2013-06-11 Takao Satoh

We prove that the full automorphism group and the outer automorphism group of the free group of countably infinite rank are coarsely bounded. That is, these groups admit no continuous actions on a metric space with unbounded orbits, and…

Group Theory · Mathematics 2023-04-11 George Domat , Hannah Hoganson , Sanghoon Kwak

We describe, up to degree equal to the rank, the Lie algebra associated with the automorphism group of a free group. We compute in particular the ranks of its homogeneous components, and their structure as modules over the linear group.…

Group Theory · Mathematics 2016-09-28 Laurent Bartholdi

We prove that in dimensions not equal to 4, 5, or 7, the homology and homotopy groups of the classifying space of the topological group of diffeomorphisms of a disk fixing the boundary are finitely generated in each degree. The proof uses…

Algebraic Topology · Mathematics 2019-10-23 Alexander Kupers

We study automorphisms of the free associative algebra K<x,y,z> over a field K which fix the variable z. We describe the structure of the group of z-tame automorphisms and derive algorithms which recognize z-tame automorphisms and z-tame…

Rings and Algebras · Mathematics 2007-05-23 Vesselin Drensky , Jie-Tai Yu

We study domains in complex $n$-space with automorphism group that does not depend on the full $n$ dimensions of the ambient space. A sufficient geometric condition is obtained to guarantee that a domain has such a "thin" automorphism…

Complex Variables · Mathematics 2008-10-28 Jisoo Byun , Steven G. Krantz

In this paper, the problem formulated in [8] is solved. We prove, that the group of automorphisms of the category of free associative algebras is generated by semi-inner and mirror automorphisms

Rings and Algebras · Mathematics 2007-05-23 Aivars Berzins

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

We compute the cohomology groups of the automorphism group of the free group $F_n$, with coefficients in arbitrary tensor products of the standard representation $H_1(F_n, \mathbb{Q})$ and its dual, in a range where $n$ is sufficiently…

Algebraic Topology · Mathematics 2025-08-22 Erik Lindell

Let $K$ be a field and $f:\mathbb{P}^N \to \mathbb{P}^N$ a morphism. There is a natural conjugation action on the space of such morphisms by elements of the projective linear group $\text{PGL}_{N+1}$. The group of automorphisms, or…

Number Theory · Mathematics 2016-04-12 Joao Alberto de Faria , Benjamin Hutz

We determine the structure of automorphism groups of finite graphs of bounded Hadwiger number. Our proof includes a structural analysis of finite edge-transitive graphs. In particular, we show that for connected, $K_{h+1}$-minor-free,…

Combinatorics · Mathematics 2025-09-24 Martin Grohe , Pascal Schweitzer , Daniel Wiebking

In this paper we consider some classical varieties of linear algebras over the field which has characteristic 0. For every considered variety we take a category of the finite generated free algebras of this variety. And for every this…

Rings and Algebras · Mathematics 2012-10-25 A. Tsurkov

We show that the natural map from the mapping class groups of surfaces to the automorphism groups of free groups, induces an infinite loop map on the classifying spaces of the stable groups after plus construction. The proof uses…

Algebraic Topology · Mathematics 2008-01-15 Nathalie Wahl

In this article, we characterize the (covariant) isotropy groups of free, finitely generated racks and quandles. As a consequence, we show that the usual inner automorphisms of such racks and quandles are precisely those automorphisms that…

Category Theory · Mathematics 2020-10-30 Jason Parker

We prove a theorem relating the automorphism group of a Cartan geometry to the group on which the geometry is modeled: a component of the adjoint representation of the first embeds in the adjoint representation of the second. Consequences…

Differential Geometry · Mathematics 2007-09-26 Uri Bader , Charles Frances , Karin Melnick

In this paper we show that an affine space is determined by the abstract group structure of its group of regular automorphisms in the category of connected affine varieties. To prove this we study commutative subgroups of the group of…

Algebraic Geometry · Mathematics 2022-03-17 Serge Cantat , Andriy Regeta , Junyi Xie