English
Related papers

Related papers: Compact Lie Groups and Complex Reductive Groups

200 papers

We extend the homotopy theories based on point reduction for finite spaces and simplicial complexes to finite acyclic categories and $\Delta$-complexes, respectively. The functors of classifying spaces and face posets are compatible with…

Algebraic Topology · Mathematics 2017-07-06 Kohei Tanaka

We construct classifying spaces for discrete and compact Lie groups, with the property that they are topological groups and complete metric spaces in a natural way. We sketch a program in view of extending these constructions.

Algebraic Topology · Mathematics 2017-02-08 Ivan Marin

Here, we classify Lie groups acting isometrically on compact Lorentz manifolds, and in particular we describe the geometric structure of compact homogeneous Lorentz manifolds.

Differential Geometry · Mathematics 2009-09-25 Abdelghani Zeghib

We consider (compact or noncompact) Lorentzian manifolds whose holonomy group has compact closure. Among other results, we obtain that this property is equivalent to admitting a parallel timelike vector field. We also derive some properties…

Differential Geometry · Mathematics 2016-03-24 Manuel Gutiérrez , Olaf Müller

This paper gives an introduction to the homotopy theory of quasi-categories. Weak equivalences between quasi-categories are characterized as maps which induce equivalences on a naturally defined system of groupoids. These groupoids…

Category Theory · Mathematics 2019-09-19 J. F. Jardine

An almost Abelian Lie group is a non-Abelian Lie group with a codimension 1 Abelian subgroup. We show that all discrete subgroups of complex simply connected almost Abelian groups are finitely generated. The topology of connected almost…

Group Theory · Mathematics 2023-08-17 Zhirayr Avetisyan , Oderico-Benjamin Buran , Andrew Paul , Lisa Reed

We prove that the discontinuity group of every locally bounded homomorphism of a Lie group into a Lie group is not only compact and connected, which is known, but is also commutative.

Representation Theory · Mathematics 2023-12-04 A. I. Shtern

In this short note we show that the path-connected component of the identity of the derived subgroup of a compact Lie group consists just of commutators. We also discuss an application of our main result to the homotopy type of the…

Group Theory · Mathematics 2023-09-06 Juan Omar Gómez , Victor Torres-Castillo , Bernardo Villarreal

This paper proves that the two homotopy theories for orbispaces given by Gepner and Henriques and by Schwede, respectively, agree by providing a zig-zag of Dwyer-Kan equivalences between the respective topologically enriched index…

Algebraic Topology · Mathematics 2018-03-13 Alexander Körschgen

We classify irreducible representations of connected compact Lie groups whose orbit space is isometric to the orbit space of a representation of a finite extension of (positive dimensional) toric group. They turn out to be exactly the…

Differential Geometry · Mathematics 2012-12-27 Claudio Gorodski , Alexander Lytchak

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

We study analogues of Cartan decompositions of Lie groups for totally disconnected locally compact groups. It is shown using these decompositions that a large class of totally disconnected locally compact groups acting on trees and…

Group Theory · Mathematics 2025-03-28 Max Carter , George A. Willis

Motivated by the study of the interrelation between functorial and algebraic quantum field theory, we point out that on any locally trivial bundle of compact groups, representations up to homotopy are enough to separate points by means of…

Differential Geometry · Mathematics 2015-12-03 Giorgio Trentinaglia , Chenchang Zhu

We generalize the concepts of locally presentable and accessible categories. Our framework includes such categories as small presheaves over large categories and ind-categories. This generalization is intended for applications in the…

Category Theory · Mathematics 2012-06-05 Boris Chorny , Jiri Rosicky

For each positive integer Q there exists a path connected metric compactum X such that the Qth-homotopy group of X is compactly generated but not a topological group (with the quotient topology).

Algebraic Topology · Mathematics 2011-06-01 Paul Fabel

A pointwise-elliptic subset of a topological group is one whose elements all generate relatively-compact subgroups. A connected locally compact group has a dense pointwise-elliptic subgroup if and only if it is an extension by a compact…

Group Theory · Mathematics 2025-06-27 Alexandru Chirvasitu

This paper explores the interplay between category theory, topology, and the algebraic theory of finite groups. Our analysis unfolds in three stages. First, we establish the foundational universe of our objects: the complete and cocomplete…

Category Theory · Mathematics 2026-03-02 Ismael Gutierrez Garcia , Luz Adriana Mejía Castaño

The homotopy category of complexes of projective left-modules over any reasonably nice ring is proved to be a compactly generated triangulated category, and a duality is given between its subcategory of compact objects and the finite…

Rings and Algebras · Mathematics 2007-05-23 Peter Jorgensen

A 1-truncated compact Lie group is any extension of a finite group by a torus. In this note we compute the homotopy types of $Map_*(BG,BH)$, $Map(BG,BH)$, and $Map(EG, B_GH)^G$ for compact Lie groups $G$ and $H$ with $H$ 1-truncated,…

Algebraic Topology · Mathematics 2018-03-16 Charles Rezk

It is shown that a closed solvable subgroup of a connected Lie group is compactly generated. In particular, every discrete solvable subgroup of a connected Lie group is finitely generated. Generalizations to locally compact groups are…

Group Theory · Mathematics 2011-02-19 Karl Heinrich Hofmann , Karl-Hermann Neeb