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Related papers: On the Baum-Connes Conjecture for Groups Acting on…

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We construct a Baum--Connes assembly map localised at the unit element of a discrete group $\Gamma$. This morphism, called $\mu_\tau$, is defined in $KK$-theory with coefficients in $\mathbb{R}$ by means of the action of the projection…

Operator Algebras · Mathematics 2020-09-10 Paolo Antonini , Sara Azzali , Georges Skandalis

We prove the $K$-theoretic Farrell-Jones conjecture for groups as in the title with coefficient rings and $C^*$-algebras which are stable with respect to compact operators. We use this and Higson-Kasparov's result that the Baum-Connes…

K-Theory and Homology · Mathematics 2014-12-16 Guillermo Cortiñas , Gisela Tartaglia

We prove the bounded packing property for any abelian subgroup of a group acting properly and cocompactly on a CAT(0) cube complex. A main ingredient of the proof is a cubical flat torus theorem. This ingredient is also used to show that…

Group Theory · Mathematics 2017-03-14 Daniel T. Wise , Daniel J. Woodhouse

In this article we give a characterisation of the Baum-Connes assembly map with coefficients. The technical tools needed are the K-theory of C*-categories, and equivariant KK-theory in the world of groupoids.

K-Theory and Homology · Mathematics 2007-05-23 Paul D. Mitchener

Let G be a discrete group and let X be a G-finite, proper G-CW-complex. We prove that Kasparov's equivariant K-homology groups KK^G(C_0(X),\C) are isomorphic to the geometric equivariant K-homology groups of X that are obtained by making…

K-Theory and Homology · Mathematics 2012-10-12 Paul Baum , Nigel Higson , Thomas Schick

We prove the Borel Conjecture for a class of groups containing word-hyperbolic groups and groups acting properly, isometrically and cocompactly on a finite dimensional CAT(0)-space.

Geometric Topology · Mathematics 2010-03-26 Arthur Bartels , Wolfgang Lueck

We present an alternative approach to the result of Guentner, Higson, and Weinberger concerning the Baum-Connes conjecture for finitely generated subgroups of SL(2,C). Using finite-dimensional methods, we show that the Baum-Connes assembly…

Group Theory · Mathematics 2007-12-24 Dmitry Matsnev

Given a (not necessarily discrete) proper metric space $M$ with bounded geometry, we define a groupoid $G(M)$. We show that the coarse Baum--Connes conjecture with coefficients, which states that the assembly map with coefficients for G(M)…

Operator Algebras · Mathematics 2010-05-05 Jean-Louis Tu

We study the coarse Baum-Connes conjecture for product spaces and product groups. We show that a product of CAT(0) groups, polycyclic groups and relatively hyperbolic groups which satisfy some assumptions on peripheral subgroups, satisfies…

K-Theory and Homology · Mathematics 2024-02-20 Tomohiro Fukaya , Shin-ichi Oguni

We compute the equivariant $K$-homology of the classifying space for proper actions, for compact 3-dimensional hyperbolic reflection groups. This coincides with the topological $K$-theory of the reduced $C^\ast$-algebra associated to the…

K-Theory and Homology · Mathematics 2020-08-05 Jean-François Lafont , Ivonne J. Ortiz , Alexander Rahm , Rubén J. Sánchez-García

We consider the equivariant K-theory of a real semisimple Lie group which acts on the (complex) flag variety of its complexification group. We construct an assemble map in the framework of KK-theory and then we prove that it is an…

K-Theory and Homology · Mathematics 2021-03-09 Zhaoting Wei

We give a new proof of some cases of the Baum-Connes conjecture along the lines of a proof of the Farrell-Jones conjecture.

Algebraic Topology · Mathematics 2013-03-05 Fabian Lenhardt

We examine a condition on a simply connected 2-complex X ensuring that groups acting properly on X are coherent. This extends earlier work on 2-complexes with negative sectional curvature which covers the case that G acts freely. Our…

Group Theory · Mathematics 2016-02-17 Eduardo Martínez-Pedroza , Daniel T. Wise

For an extension $1\rightarrow N \rightarrow \Gamma \xrightarrow{q} \Gamma / N \rightarrow 1$ of discrete countable groups, it is known that the Baum-Connes conjecture with coefficients holds for $\Gamma$ if it holds for $\Gamma / N$ and…

Operator Algebras · Mathematics 2025-08-26 Jianguo Zhang

We associate a non-commutative $C^*$-algebra with any locally finite simplicial complex. We determine the $K$-theory of these algebras and show that they can be used to obtain a conceptual explanation for the Baum-Connes conjecture.

Operator Algebras · Mathematics 2007-05-23 Joachim Cuntz

We prove a sharp, quantitative analogue of Helgason's conjecture at the level of distributions: For a semisimple Lie group $G$ of real rank one, Poisson transforms map a Sobolev space on $P\backslash G$ boundedly with closed range to an…

K-Theory and Homology · Mathematics 2026-04-08 Heiko Gimperlein , Magnus Goffeng

We introduce a new variant of the coarse Baum-Connes conjecture designed to tackle coarsely disconnected metric spaces called the boundary coarse Baum-Connes conjecture. We prove this conjecture for many coarsely disconnected spaces that…

K-Theory and Homology · Mathematics 2014-07-23 Martin Finn-Sell , Nick Wright

In this paper we introduce a common framework for describing the topological part of the Baum-Connes conjecture for a wide class of groups. We compute the Bredon homology for groups with aspherical presentation, one-relator quotients of…

K-Theory and Homology · Mathematics 2013-09-23 Yago Antolín , Ramón Flores

In this paper, we use the KK-theory of Kasparov to prove exactness of sequences relating the K-theory of a real C^*-algebra and of its complexification (generalizing results of Boersema). We use this to relate the real version of the…

K-Theory and Homology · Mathematics 2014-10-01 Thomas Schick

The equivariant coarse index is well-understood and widely used for actions by discrete groups. We extend the definition of this index to general locally compact groups. We use a suitable notion of admissible modules over $C^*$-algebras of…

K-Theory and Homology · Mathematics 2022-07-05 Hao Guo , Peter Hochs , Varghese Mathai