English
Related papers

Related papers: $C^*$-independence for $\mathbb{Z}_2$-graded $C^*$…

200 papers

We introduce the completely positive rank, a notion of covering dimension for nuclear $C^*$-algebras and analyze some of its properties. The completely positive rank behaves nicely with respect to direct sums, quotients, ideals and…

Operator Algebras · Mathematics 2007-05-23 Wilhelm Winter

Let $K$ be an infinite field of characteristic different from two and let $U_1$ be the Lie algebra of the derivations of the algebra of Laurent polynomials $K[t,t^{-1}]$. The algebra $U_1$ admits a natural $\mathbb{Z}$-grading. We provide a…

Rings and Algebras · Mathematics 2021-07-26 Claudemir Fidelis , Plamen Koshlukov

In this paper, we study the boundary quotient C*-algebras associated to products of odometers. One of our main results shows that the boundary quotient C*-algebra of the standard product of $k$ odometers over $n_i$-letter alphabets ($1\le…

Operator Algebras · Mathematics 2017-05-08 Hui Li , Dilian Yang

It is shown that, for a C*-algebra of stable rank one (i.e., in which the invertible elements are dense), two well-known isomorphism invariants, the Cuntz semigroup and the Thomsen semigroup, contain the same information. More precisely,…

Operator Algebras · Mathematics 2011-11-10 Alin Ciuperca , George A. Elliott

We prove a uniqueness theorem and give a characterization of simplicity for Steinberg algebras associated to non-Hausdorff ample groupoids. We also prove a uniqueness theorem and give a characterization of simplicity for the C*-algebra…

Operator Algebras · Mathematics 2019-05-17 Lisa Orloff Clark , Ruy Exel , Enrique Pardo , Aidan Sims , Charles Starling

The C*-algebra of bounded operators on the separable infinite-dimensional Hilbert space cannot be mapped to a W*-algebra in such a way that each unital commutative C*-subalgebra C(X) factors normally through $\ell^\infty(X)$. Consequently,…

Operator Algebras · Mathematics 2016-08-05 Chris Heunen , Manuel L. Reyes

We characterize the lifting property (LP) of a separable $C^*$-algebra $A$ by a property of its maximal tensor product with other $C^*$-algebras, namely we prove that $A$ has the LP if and only if for any family $(\{D_i\mid i\in I\}$ of…

Operator Algebras · Mathematics 2023-04-05 Gilles Pisier

We study the general and connected stable ranks for C*-algebras. We estimate these ranks for pullbacks of C*-algebras, and for tensor products by commutative C*-algebras. Finally, we apply these results to determine these ranks for certain…

Operator Algebras · Mathematics 2018-06-26 Prahlad Vaidyanathan

Examples of simple, separable, unital, purely infinite $C^*$--algebras are constructed, including: (1) some that are not approximately divisible; (2) those that arise as crossed products of any of a certain class of $C^*$--algebras by any…

funct-an · Mathematics 2016-08-31 Kenneth J. Dykema , Mikael Rordam

Motivated by some recent results, we consider the notion of eigenstate (and eigenvalue) for an element $X$ of a CQ*-algebras and the consequences on algebraic quantum dynamics and on its related derivations are investigated.

Operator Algebras · Mathematics 2025-10-14 Fabio Bagarello , Hiroshi Inoue , Camillo Trapani , Salvatore Triolo

In this paper we describe a new method of defining C*-algebras from oriented combinatorial data, thereby generalizing the constructions of algebras from directed graphs, higher-rank graphs, and ordered groups. We show that only the most…

Operator Algebras · Mathematics 2014-05-21 Jack Spielberg

We prove that faithful traces on separable and nuclear C*-algebras in the UCT class are quasidiagonal. This has a number of consequences. Firstly, by results of many hands, the classification of unital, separable, simple and nuclear…

Operator Algebras · Mathematics 2016-12-07 Aaron Tikuisis , Stuart White , Wilhelm Winter

We compute the two-cocycles (or multipliers) of the free nilpotent groups of class $2$ and rank $n$ and give conditions for simplicity of the corresponding twisted group $C^*$-algebras. These groups are representation groups for…

Operator Algebras · Mathematics 2016-07-08 Tron Omland

A finite hypergraph $H$ consists of a finite set of vertices $V(H)$ and a collection of subsets $E(H) \subseteq 2^{V(H)}$ which we consider as partition of unity relations between projection operators. These partition of unity relations…

Operator Algebras · Mathematics 2020-04-06 Tobias Fritz

We study nonunital $C^*$-algebras such that for any element there exists a local unit and prove that in such algebras there are no frames. This fact was previously known only for commutative algebras. Among other results, we establish some…

Operator Algebras · Mathematics 2025-06-17 Denis Fufaev

We initiate the study of computable presentations of real and complex C*-algebras under the program of effective metric structure theory. With the group situation as a model, we develop corresponding notions of recursive presentations and…

Logic · Mathematics 2023-04-17 Alec Fox

A $\Sigma^*$-algebra is a concrete $C^*$-algebra that is sequentially closed in the weak operator topology. We study an appropriate class of $C^*$-modules over $\Sigma^*$-algebras analogous to the class of $W^*$-modules (selfdual…

Operator Algebras · Mathematics 2016-09-13 Clifford A. Bearden

We establish new metric characterizations for the norm (respectively, ultraweak) closure of the convex hull of a bounded set in an arbitrary $C^*$-algebra (respectively, von Neumann algebra), and provide applications of these results to the…

Operator Algebras · Mathematics 2024-05-29 Mikaël Pichot , Erik Séguin

We shall introduce the notion of the Picard group for an inclusion of $C^*$-algebras. We shall also study its basic properties and the relation between the Picard group for an inclusion of $C^*$-algebras and the ordinary Picard group.…

Operator Algebras · Mathematics 2019-05-21 Kazunori Kodaka

In this paper we introduce the M\"obius disjointness for C$^*$-algebras with their automorphisms and studied the M\"obius disjointness for finite dimensional C$^*$ algebras, finite von Neumann algebras, reduced free group algebra and…

Operator Algebras · Mathematics 2015-06-23 Jinsong Wu , Wei Yuan