English
Related papers

Related papers: A revised augmented Cuntz semigroup

200 papers

A $C^*$-algebra satisfies the Universal Coefficient Theorem (UCT) of Rosenberg and Schochet if it is equivalent in Kasparov's $KK$-theory to a commutative $C^*$-algebra. This paper is motivated by the problem of establishing the range of…

Operator Algebras · Mathematics 2023-07-14 Rufus Willett , Guoliang Yu

Let $X$ be a finite dimensional compact metrizable space. We study a technique which employs semiprojectivity as a tool to produce approximations of $C(X)$-algebras by $C(X)$-subalgebras with controlled complexity. The following…

Operator Algebras · Mathematics 2009-07-17 Marius Dadarlat

For each odd integer $n \geq 3$, we construct a rank-3 graph $\Lambda_n$ with involution $\gamma_n$ whose real C*-algebra $C^*_\mathbb{R}(\Lambda_n, \gamma_n)$ is stably isomorphic to the exotic Cuntz algebra $\mathcal E_n^\mathbb{R}$. This…

Operator Algebras · Mathematics 2023-05-10 Jeffrey L. Boersema , Sarah L. Browne , Elizabeth Gillaspy

We study the structure and compute the stable rank of C*-algebras of finite higher-rank graphs. We completely determine the stable rank of the C*-algebra when the k-graph either contains no cycle with an entrance, or is cofinal. We also…

Operator Algebras · Mathematics 2021-09-08 David Pask , Adam Sierakowski , Aidan Sims

It is well-known that every commutative separable unital C*-algebra of real rank zero is a quotient of the C*-algebra of all compex continous functions defined on the Cantor cube. We prove a non-commutative version of this result by showing…

Operator Algebras · Mathematics 2007-05-23 Alex Chigogidze

This paper investigates and classifies a specific class of one-parameter continuous fields of C*-algebras, which can be seen as generalized AI-algebras. Building on the classification of *-homomorphisms between interval algebras by the…

Operator Algebras · Mathematics 2026-01-08 Laurent Cantier

We provide a reference for basic categorial properties of the categories of (possibly non-unital) $\mathbb{C}$-linear $*$-categories or $C^{*}$-categories, and (not necessarily unit-preserving) functors. Generalizing the classical case of…

Operator Algebras · Mathematics 2021-12-13 Ulrich Bunke

We introduce the notion of continuous twisted partial actions of a locally compact group on a C*-algebra. With such, we construct an associated C*-algebraic bundle called the semidirect product bundle. Our main theorem shows that, given any…

funct-an · Mathematics 2008-02-03 Ruy Exel

We introduce and analyse the structure of C*-algebras arising from ideals in right tensor C*-precategories, which naturally generalize both relative Cuntz-Pimsner and Doplicher-Roberts algebras. We establish an explicit intrinsic…

Operator Algebras · Mathematics 2013-08-27 B. K. Kwaśniewski

In this paper we exploit the fact that a Cuntz C$^*$-algebra is a groupoid C$^*$-algebra to facilitate the study of non-self-adjoint subalgebras of $O_n$. The Cuntz groupoid is not principal and the spectral theorem for bimodules does not…

Operator Algebras · Mathematics 2007-05-23 Alan Hopenwasser , Justin R. Peters

We show that a C*-algebra "looking like" a Cuntz-Krieger algebra is a Cuntz-Krieger algebra. This implies that, in an appropriate sense, the class of Cuntz-Krieger algebras is closed under extensions of real rank zero.

Operator Algebras · Mathematics 2015-12-01 Rasmus Bentmann

Extending the work of Cuntz and Vershik, we develop a general notion of independence for commuting group endomorphisms. Based on this concept, we initiate the study of irreversible algebraic dynamical systems, which can be thought of as…

Operator Algebras · Mathematics 2016-11-04 Nicolai Stammeier

The authors' recent classification of Jesper Villadsen's remarkable generalization (based on a self-reproducing seed space) of Glimm's infinite tensor product (UHF) C*-algebras, by means of the Cuntz semigroup (in the case of a fixed,…

Operator Algebras · Mathematics 2025-12-05 George A. Elliott , Zhuang Niu

We establish axiomatic characterizations of $K$-theory and $KK$-theory for real C*-algebras. In particular, let $F$ be an abelian group-valued functor on separable real C*-algebras. We prove that if $F$ is homotopy invariant, stable, and…

Operator Algebras · Mathematics 2012-10-15 Jeffrey L. Boersema , Efren Ruiz

This dissertation concerns the classification of groupoid and higher-rank graph C*-algebras and has two main components. Firstly, for a groupoid it is shown that the notions of strength of convergence in the orbit space and…

Operator Algebras · Mathematics 2013-05-28 Robert Hazlewood

The note presents a further study of the class of Cuntz--Krieger type algebras. A necessary and sufficient condition is identified that ensures that the algebra is purely infinite, the ideal structure is studied, % and applied to semigraph…

Operator Algebras · Mathematics 2017-10-18 Bernhard Burgstaller

This paper continues the study of K-theoretic invariants for semigroup C*-algebras attached to ax+b-semigroups over rings of algebraic integers in number fields. We show that from the semigroup C*-algebra together with its canonical…

Operator Algebras · Mathematics 2015-03-06 Xin Li

We show that the Cuntz splice induces stably isomorphic graph $C^*$-algebras.

Operator Algebras · Mathematics 2021-09-20 Søren Eilers , Gunnar Restorff , Efren Ruiz , Adam P. W. Sørensen

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

This paper studies the problems of embedding and isomorphism for countably generated Hilbert C*-modules over commutative C*-algebras. When the fibre dimensions differ sufficiently, relative to the dimension of the spectrum, we show that…

Operator Algebras · Mathematics 2015-06-01 Leonel Robert , Aaron Tikuisis