The topological centre of a compactification of a locally compact group.
The topological snake lemma and corona algebras.
Topological AE(0)-groups
We investigate topological AE(0)-groups, a class which contains the class of Polish groups as well as the class of all locally compact groups. We establish the existence of a universal AE(0)-group of a given weight as well as the existence of a universal action of an AE(0)-group of a given weight on an AE(0)-space of the same weight. A complete characterization of closed subgroups of powers of the symmetric group is obtained. It is also shown that every AE(0)-group is Baire isomorphic to a product...
Topological groups and uniform continuity
Topological groups with Rokhlin properties
In his classical paper [Ann. of Math. 45 (1944)] P. R. Halmos shows that weak mixing is generic in the measure preserving transformations. Later, in his book, Lectures on Ergodic Theory, he gave a more streamlined proof of this fact based on a fundamental lemma due to V. A. Rokhlin. For this reason the name of Rokhlin has been attached to a variety of results, old and new, relating to the density of conjugacy classes in topological groups. In this paper we will survey some of the new developments...
Topological type of weakly closed subgroups in Banach spaces
The main result says that nondiscrete, weakly closed, containing no nontrivial linear subspaces, additive subgroups in separable reflexive Banach spaces are homeomorphic to the complete Erdős space. Two examples of such subgroups in which are interesting from the Banach space theory point of view are discussed.
Topologisch Linksengelsche Elemente.
Topology of the isometry group of the Urysohn space
Using classical results of infinite-dimensional geometry, we show that the isometry group of the Urysohn space, endowed with its usual Polish group topology, is homeomorphic to the separable Hilbert space ℓ²(ℕ). The proof is based on a lemma about extensions of metric spaces by finite metric spaces, which we also use to investigate (answering a question of I. Goldbring) the relationship, when A,B are finite subsets of the Urysohn space, between the group of isometries fixing A pointwise, the group...
Topološki analogon Hosu-Gluškinove teoreme
Über die Einlagerung topologischer Gruppen in Kompakte
Un exemple de sous-groupe additif de l'espace de Hilbert
Uniform normality of topological groups and -groups
Unique reducibility of subsets of commutative topological groups and semigroups.
Uniqueness results for the ax+b group and related algebraic objects
Universal minimal flows of automorphism groups
Varieties of topological groups a survey
Varieties of Topological Groups Generated by Groups with Invariant Compact Neighbourhoods of the Identity
Varieties of topological groups, Lie groups and SIN-groups
In this paper we answer three open problems on varieties of topological groups by invoking Lie group theory. We also reprove in the present context that locally compact groups with arbitrarily small invariant identity neighborhoods can be approximated by Lie groups
Verbände vertauschbarer Untergruppen.
Weak continuity properties of topologized groups
We explore (weak) continuity properties of group operations. For this purpose, the Novak number and developability number are applied. It is shown that if is a regular right (left) semitopological group with such that all left (right) translations are feebly continuous, then is a topological group. This extends several results in literature.