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Wonderful compactifications of adjoint reductive groups over an algebraically closed field play an important role in algebraic geometry and representation theory. In this paper, we construct an equivariant compactification for adjoint…

Algebraic Geometry · Mathematics 2025-06-04 Shang Li

This paper is devoted to the study of noncommutative ergodic theorems for connected amenable locally compact groups. For a dynamical system $(\mathcal{M},\tau,G,\sigma)$, where $(\mathcal{M},\tau)$ is a von Neumann algebra with a normal…

Operator Algebras · Mathematics 2016-05-13 Mu Sun

We characterize group compactifications of discrete groups for which there exists an equivariant retraction onto the boundary. In particular, we prove an equivariant analogue of Brouwer's No-Retraction theorem for large classes of group…

Group Theory · Mathematics 2025-09-15 Yair Hartman , Aranka Hrušková , Mehrdad Kalantar , Tomer Zimhoni

We prove that amenability of a discrete group is equivalent to dimension flatness of certain ring inclusions naturally associated with measure preserving actions of the group. This provides a group-measure space theoretic solution to a…

Group Theory · Mathematics 2013-05-16 David Kyed , Henrik Densing Petersen

We study final group topologies and their relations to compactness properties. In particular, we are interested in situations where a colimit or direct limit is locally compact, a k_\omega-space, or locally k_\omega. As a first application,…

Group Theory · Mathematics 2015-03-27 Helge Glockner , Ralf Köhl , Tobias Hartnick

We announce an atlas of subgroup lattices of almost simple groups and present two algorithms that were used to produce the atlas.

Group Theory · Mathematics 2013-12-02 Thomas Connor , Dimitri Leemans

We generalize the Cauchy-Davenport theorem to locally compact groups.

Group Theory · Mathematics 2024-08-29 Yifan Jing , Chieu-Minh Tran

We introduce the notion of proper proximality for finite von Neumann algebras, which naturally extends the notion of proper proximality for groups. Apart from the group von Neumann algebras of properly proximal groups, we provide a number…

Operator Algebras · Mathematics 2022-11-18 Changying Ding , Srivatsav Kunnawalkam Elayavalli , Jesse Peterson

We establish the tracial stability of a certain class of graph products of C*-algebras. This result involves the development of the "pincushion class" of finite graphs. We then apply this result in two ways. The first application yields a…

Operator Algebras · Mathematics 2019-03-07 Scott Atkinson

The theory of p-local compact groups, developed in an earlier paper by the same authors, is designed to give a unified framework in which to study the p-local homotopy theory of classifying spaces of compact Lie groups and p-compact groups,…

Algebraic Topology · Mathematics 2014-11-26 Carles Broto , Ran Levi , Bob Oliver

The article is devoted to a structure of topological spaces related with topological quasigroups. Regular and complete spaces over topological quasigroups are studied. Separations and embeddings are also investigated for them. Their…

Group Theory · Mathematics 2023-12-29 S. V. Ludkowski

It is proved that a discrete group G is exact if and only if its left translation action on the Stone-Cech compactification is amenable. Combining this with an unpublished result of Gromov, we have the existence of non exact discrete…

Operator Algebras · Mathematics 2009-10-31 Narutaka Ozawa

In this paper we consider the existence of dense embeddings of Limit groups in locally compact groups generalizing earlier work of Breuillard, Gelander, Souto and Storm [GBSS] where surface groups were considered. Our main results are…

Group Theory · Mathematics 2012-04-17 Jonathan Barlev , Tsachik Gelander

We study the group of type-preserving automorphisms of a right-angled building, in particular when the building is locally finite. Our aim is to characterize the proper open subgroups as the finite index closed subgroups of the stabilizers…

Group Theory · Mathematics 2019-01-07 Tom De Medts , Ana C. Silva

We study homogeneous metric spaces, by which we mean connected, locally compact metric spaces whose isometry group acts transitively. After a review of some classical results, we use the Gleason-Iwasawa-Montgomery-Yamabe-Zippin structure…

We describe simply connected compact exceptional simple Lie groups in very elementary way. We first construct all simply connected compact exceptional Lie groups G concretely. Next, we find all involutive automorphisms of G, and determine…

Differential Geometry · Mathematics 2009-02-04 Ichiro Yokota

\noindent The most natural group topology on $\Z$ is the discrete one. There are other well-known group topologies on $\Z$, like the $p$-adic, defined for any prime number $p$. It is also an important group topology the weak topology with…

General Topology · Mathematics 2013-05-22 Daniel de la Barrera

We construct some new cohomology theories for topological groups and Lie groups and study some of its basic properties. For example, we introduce a cohomology theory based on measurable cochains which are continuous in a neighbourhood of…

General Topology · Mathematics 2010-09-24 Arati S. Khedekar , C. S. Rajan

We present an approximation theorem for continuous non-decreasing functions on compact preordered spaces, leading to an algebraic characterization of their corresponding function spaces. As an application, we prove that the family of…

Functional Analysis · Mathematics 2025-12-04 Ettore Minguzzi

The conjugacy of split Cartan subalgebras in the finite dimensional simple case (Chevalley) and in the symmetrizable Kac-Moody case (Peterson-Kac) are fundamental results of the theory of Lie algebras. Among the Kac-Moody Lie algebras the…

Rings and Algebras · Mathematics 2014-07-22 V. Chernousov , Philippe Gille , Arturo Pianzola