The problem of classifying the automorphisms of a free group of infinite countable rank is investigated. Quite a reasonable generating set for the group AutF∞ is described. Some new subgroups of this group and structural results for them are presented. The main result says that the group of all automorphisms is generated (modulo the IA-automorphisms) by strings and lower triangular automorphisms.

If W is an infinite rank 3 Coxeter group, whose Coxeter diagram has no infinite bonds, then the automorphism group of W is generated by the inner automorphisms and any automorphisms induced from automorphisms of the Coxeter diagram. Indeed Aut(W ) is the semi-direct product of Inn(W ) and the group of graph automorphisms.

This paper gives a classification up to isotopy of automorphisms (self-homeomorphisms) of 3-dimensional handlebodies and compression bodies, analogous to the Nielsen-Thurston classification of automorphisms of surfaces. Indecomposable automorphisms analogous to pseudo-Anosov automorphisms are identified and called generic. The first steps are taken towards understanding generic automorphisms us...

We study automorphisms φ of the free associative algebra K〈x, y, z〉 over a field K such that φ(x), φ(y) are linear with respect to x, y and φ(z) = z. We prove that some of these automorphisms are wild in the class of all automorphisms fixing z, including the well known automorphism discovered by Anick, and show how to recognize the wild ones. This class of automorphisms induces tame automorphis...

Let K be a field of characteristic zero. We characterize coordinates and tame coordinates in K[z][x,y], i.e. the images of x respectively under all automorphisms and under the tame automorphisms of K[z][x,y]. We also construct a new large class of wild automorphisms of K[z][x,y] which maps x to a concrete family of nice looking polynomials. We show that a subclass of this class is stably tame, ...

We investigate the question of when an ergodic automorphism T is conjugate to its composition square T 2, i.e., when does there exist an automorphism S with the property that ST = T 2S. This is a non–generic property of automorphisms which seems to be quite exceptional. The situation for ergodic automorphisms having discrete spectrum and automorphisms having the weak closure property is investi...

We classify isotopy classes of automorphisms (self-homeomorphisms) of 3manifolds satisfying the Thurston Geometrization Conjecture. The classification is similar to the classification of automorphisms of surfaces developed by Nielsen and Thurston, except an automorphism of a reducible manifold must first be written as a suitable composition of two automorphisms, each of which fits into our clas...

Let W be a variety of groups defined by a set W of laws and G be a finite p-group in W. The automorphism α of a group G is said to bea marginal automorphism (with respect to W), if for all x ∈ G, x−1α(x) ∈ W∗(G), where W∗(G) is the marginal subgroup of G. Let M,N be two normalsubgroups of G. By AutM(G), we mean the subgroup of Aut(G) consistingof all automorphisms which centralize G/M. AutN(G) ...

In 2004, Shestakov and Umirbaev proved that the Nagata automorphism of polynomial algebra in three variables is wild. We fix a [Formula: see text]-grading on this consider graded-wild automorphisms, i.e. such automorphisms cannot be decomposed onto elementary respecting grading. describe all gradings allowing automorphisms.

We determine which simple algebraic groups of type D4 over arbitrary fields of characteristic different from 2 admit outer automorphisms of order 3, and classify these automorphisms up to conjugation. The criterion is formulated in terms of a representation of the group by automorphisms of a trialitarian algebra: outer automorphisms of order 3 exist if and only if the algebra is the endomorphis...