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In this paper, we generalize the Dirac-dual-Dirac method to Hecke pairs with equivariant coarse embeddings and establish the K-theoretic isomorphisms between the maximal and reduced equivariant Roe algebras. We also extend these results to…

K-Theory and Homology · Mathematics 2026-02-03 Liang Guo , Hang Wang , Xiufeng Yao

Let $X$ be a discrete metric space with bounded geometry. We show that if $X$ admits an "A-by-CE coarse fibration", then the canonical quotient map $\lambda: C^*_{\max}(X)\to C^*(X)$ from the maximal Roe algebra to the Roe algebra of $X$,…

Operator Algebras · Mathematics 2021-11-12 Liang Guo , Zheng Luo , Qin Wang , Yazhou Zhang

In this paper, the second of a series of two, we continue the study of higher index theory for expanders. We prove that if a sequence of graphs has girth tending to infinity, then the maximal coarse Baum-Connes assembly map is an…

K-Theory and Homology · Mathematics 2010-12-21 Rufus Willett , Guoliang Yu

We document some versions, in real K-theory, of well-known properties of the coarse assembly map in complex K-theory. These results are well-known, but difficult to find in the literature.

K-Theory and Homology · Mathematics 2013-08-13 John Roe

This paper studies higher index theory for a random sequence of bounded degree, finite graphs with diameter tending to infinity. We show that in a natural model for such random sequences the following hold almost surely: the coarse…

K-Theory and Homology · Mathematics 2014-04-28 Rufus Willett

We prove that uniform Roe C*-algebras associated to some expander graphs coming from discrete groups with property (\tau) are not K-exact. In particular, we show that this is the case for the expander obtained as Cayley graphs of a sequence…

Operator Algebras · Mathematics 2009-07-15 Jan Spakula

Gong, Wang and Yu introduced a maximal, or universal, version of the Roe C*-algebra associated to a metric space. We study the relationship between this maximal Roe algebra and the usual version, in both the uniform and non-uniform cases.…

K-Theory and Homology · Mathematics 2011-10-10 Jan Spakula , Rufus Willett

In this paper, the first of a series of two, we continue the study of higher index theory for expanders. We prove that if a sequence of graphs is an expander and the girth of the graphs tends to infinity, then the coarse Baum-Connes…

K-Theory and Homology · Mathematics 2010-12-21 Rufus Willett , Guoliang Yu

Using a combination of Atiyah-Segal ideas on one side and of Connes and Baum-Connes ideas on the other, we prove that the Twisted geometric K-homology groups of a Lie groupoid have an external multiplicative structure extending hence the…

K-Theory and Homology · Mathematics 2016-03-31 Noé Bárcenas , Paulo Carrillo Rouse , Mario Velásquez

In this note we set a configuration space description of the equivariant connective K-homology groups with coefficients in a unital C*-algebra for proper actions. Over this model we define a connective assembly map and prove that in this…

K-Theory and Homology · Mathematics 2019-02-04 Mario Velásquez

We develop a generalization of quantitative $K$-theory, which we call controlled $K$-theory. It is powerful enough to study the $K$-theory of crossed product of $C^*$-algebras by action of \'etale groupoids and discrete quantum groups. In…

K-Theory and Homology · Mathematics 2017-10-18 Clément Dell'Aiera

We study an equivariant co-assembly map that is dual to the usual Baum-Connes assembly map and closely related to coarse geometry, equivariant Kasparov theory, and the existence of dual Dirac morphisms. As applications, we prove the…

K-Theory and Homology · Mathematics 2015-10-23 Heath Emerson , Ralf Meyer

In this article we use existing machinery to define connective $K$-theory spectra associated to topological ringoids. Algebraic $K$-theory of discrete ringoids, and the analytic $K$-theory of Banach categories are obtained as special cases.…

K-Theory and Homology · Mathematics 2007-11-15 Paul D. Mitchener

In this paper, we introduce a notion of twisted Roe algebra and a twisted coarse Baum-Connes conjecture with coefficients. We will study the basic properties of twisted Roe algebras, including a coarse analogue of the imprimitivity theorem…

K-Theory and Homology · Mathematics 2025-05-27 Jintao Deng , Liang Guo

For every strong coarse homology theory we construct a coarse assembly map as a natural transformation between coarse homology theories. We provide various conditions implying that this assembly map is an equivalence. These results…

K-Theory and Homology · Mathematics 2020-08-26 Ulrich Bunke , Alexander Engel

This paper investigates the $\mathrm{K}$-theory of twisted groupoid $\mathrm{C}^*$-algebras. It is shown that a homotopy of twists on an ample groupoid satisfying the Baum-Connes conjecture with coefficients gives rise to an isomorphism…

Operator Algebras · Mathematics 2019-04-25 Christian Bönicke

Using the Evans spectral sequence and its counter-part for real $K$-theory, we compute both the real and complex $K$-theory of several infinite families of $C^*$-algebras based on higher-rank graphs of rank $3$ and $4$. The higher-rank…

Operator Algebras · Mathematics 2025-02-26 Jeffrey L Boersema , Alina Vdovina

In this paper we study the index theoretic interpretation of the analytical assembly map that appears in the Baum-Connes conjecture. In its general form it may be constructed using Kasparov's equivariant KK-theory. In the special case of a…

K-Theory and Homology · Mathematics 2014-03-07 Markus Land

We prove that the coarse assembly maps for proper metric spaces which are non-positively curved in the sense of Busemann are isomorphisms, where we do not assume that the spaces are with bounded coarse geometry. Also it is shown that we can…

K-Theory and Homology · Mathematics 2018-10-23 Tomohiro Fukaya , Shin-ichi Oguni

We define and study an analogue of the Baum-Connes assembly map for complex semisimple quantum groups, that is, Drinfeld doubles of $ q $-deformations of compact semisimple Lie groups. Our starting point is the deformation picture of the…

Operator Algebras · Mathematics 2018-04-26 Andrew Monk , Christian Voigt
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