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Related papers: $K$-theory for real $k$-graph $C^*$-algebras

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Spielberg's construction of C*-algebras from left cancellative small categories is a common generalization for most C*-algebras one would consider to come from ``combinatorial data,'' including graph and $k$-graph C*-algebras, Li's…

Operator Algebras · Mathematics 2026-05-14 Charles Starling

We define the notion of a $\Lambda$-system of $C^*$-correspondences associated to a higher-rank graph $\Lambda$. Roughly speaking, such a system assigns to each vertex of $\Lambda$ a $C^*$-algebra, and to each path in $\Lambda$ a…

Operator Algebras · Mathematics 2009-02-17 Valentin Deaconu , Alex Kumjian , David Pask , Aidan Sims

We develop a theory of graph C*-algebras using path groupoids and inverse semigroups. Row finiteness is not assumed so that the theory applies to graphs for which there are vertices emitting a countably infinite set of edges. We show that…

Operator Algebras · Mathematics 2007-05-23 Alan L. T. Paterson

We introduce the notion of a topological higher-rank graph, a unified generalization of the higher-rank graph and the topological graph. Using groupoid techniques, we define the Toeplitz and Cuntz-Krieger algebras of topological higher-rank…

Operator Algebras · Mathematics 2007-05-23 Trent Yeend

We study stable finiteness of extensions of 2-graph C*-algebras determined by saturated hereditary sets of vertices. We use two iterations of the Pimsner-Voiculescu sequence to calculate the map in K-theory induced by the inclusion of a…

Operator Algebras · Mathematics 2021-12-01 Astrid an Huef , Abraham C. S. Ng , Aidan Sims

A semigroupoid is a set equipped with a partially defined associative operation. Given a semigroupoid \Lambda we construct a C*-algebra C*(\Lambda) from it. We then present two main examples of semigroupoids, namely the Markov semigroupoid…

Operator Algebras · Mathematics 2007-05-23 Ruy Exel

We present the first range result for the total K-theory of C*-algebras. This invariant has been used successfully to classify certain separable, nuclear C*-algebras of real rank zero. Our results complete the classification of the…

Operator Algebras · Mathematics 2007-05-23 Soren Eilers , Andrew S. Toms

This is a survey article with the goal to advertise spectrum valued versions of $K$- and $KK$- theory for $C^{*}$-algebras via a (stable and symmetric monoidal) $\infty$-categorical enhancement of Kasparov's classical $KK$-theory. The main…

Operator Algebras · Mathematics 2023-11-30 Ulrich Bunke , Markus Land , Ulrich Pennig

We develop notions of a representation of a topological graph E and of a covariant representation of a topological graph E which do not require the machinery of C*-correspondences and Cuntz-Pimsner algebras. We show that the C*-algebra…

Operator Algebras · Mathematics 2012-05-16 Hui Li , David Pask , Aidan Sims

We classify the gauge-invariant ideals in the C*-algebras of infinite directed graphs, and describe the quotients as graph algebras. We then use these results to identify the gauge-invariant primitive ideals in terms of the structural…

Operator Algebras · Mathematics 2007-05-23 Teresa Bates , Jeong Hee Hong , Iain Raeburn , Wojciech Szymanski

The goal of these notes is to present the C*-algebra $C^*(B,L,\theta)$ of a Boolean dynamical system $(B,L,\theta)$, that generalizes the $C^*$-algebra associated to Labelled graphs introduced by Bates and Pask, and to determine its…

Operator Algebras · Mathematics 2017-05-23 Toke Meier Carlsen , Eduard Ortega , Enrique Pardo

An action of Z^l by automorphisms of a k-graph induces an action of Z^l by automorphisms of the corresponding k-graph C*-algebra. We show how to construct a (k+l)-graph whose C*-algebra coincides with the crossed product of the original…

Operator Algebras · Mathematics 2007-06-26 Cynthia Farthing , David Pask , Aidan Sims

We study $C^*$-algebras arising from $C^*$-correspondences, which was introduced by the author. We prove the gauge-invariant uniqueness theorem, and obtain conditions for our $C^*$-algebras to be nuclear, exact, or satisfy the Universal…

Operator Algebras · Mathematics 2007-05-23 Takeshi Katsura

In an earlier paper, the authors introduced partial translation algebras as a generalisation of group C*-algebras. Here we establish an extension of partial translation algebras, which may be viewed as an excision theorem in this context.…

Operator Algebras · Mathematics 2013-04-29 Jacek Brodzki , Graham A. Niblo , Nick Wright

We define united K-theory for real C*-algebras, generalizing Bousfield's topological united K-theory. United K-theory incorporates three functors -- real K-theory, complex K-theory, and self-conjugate K-theory -- and the natural…

Operator Algebras · Mathematics 2007-05-23 Jeffrey L. Boersema

We show that the C*-algebra of a row-finite source-free k-graph is Rieffel-Morita equivalent to a crossed product of an AF algebra by the fundamental group of the k-graph. When the k-graph embeds in its fundamental groupoid, this AF algebra…

Operator Algebras · Mathematics 2024-03-05 Nathan Brownlowe , Alex Kumjian , David Pask , Aidan Sims

In previous work, the authors showed that the C*-algebra C*(\Lambda) of a row-finite higher-rank graph \Lambda with no sources is simple if and only if \Lambda is both cofinal and aperiodic. In this paper, we generalise this result to…

Operator Algebras · Mathematics 2010-01-13 David I. Robertson , Aidan Sims

We reveal a correspondence between the homological torsion of the Bianchi groups and new geometric invariants, which are effectively computable thanks to their action on hyperbolic space. We use it to explicitly compute their integral group…

K-Theory and Homology · Mathematics 2011-09-09 Alexander D. Rahm

We introduce a family of $C^*$-correspondences $X_\alpha$ naturally associated to every ordinal graph $\Lambda$. When $\Lambda$ is a directed graph, $X_0$ is isomorphic to the usual $C^*$-correspondence associated to a graph. We show that…

Operator Algebras · Mathematics 2026-02-18 Benjamin Jones

We compute the $K$-theory of comparison $C^*$-algebra associated to a manifold with corners. These comparison algebras are an example of the abstract pseudodifferential algebras introduced by Connes and Moscovici \cite{M3}. Our calculation…

K-Theory and Homology · Mathematics 2010-05-12 Bertrand Monthubert , Victor Nistor
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