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Related papers: Property (T) for non-unital C*-algebras

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An action of a compact, in particular finite group on a C*-algebra is called properly outer if no automorphism of the group that is distinct from identity is implemented by a unitary element of the algebra of local multipliers of the…

Operator Algebras · Mathematics 2024-12-03 Costel Peligrad

We present a classification theorem for a class of unital simple separable amenable ${\cal Z}$-stable $C^*$-algebras by the Elliott invariant. This class of simple $C^*$-algebras exhausts all possible Elliott invariant for unital stably…

Operator Algebras · Mathematics 2015-11-17 Guihua Gong , Huaxin Lin , Zhuang Niu

We define a "tracial" analog of the Rokhlin property for actions of second countable compact groups on infinite dimensional simple separable unital C*-algebras. We prove that fixed point algebras under such actions (and, in the appropriate…

Operator Algebras · Mathematics 2022-06-20 Javad Mohammadkarimi , N. Christopher Phillips

The category of $C^*$-algebras is blessed with many different tensor products. In contrast, virtually the only tensor product ever used in the category of von Neumann algebras is the normal spatial tensor product. We propose a definition of…

Operator Algebras · Mathematics 2015-06-05 Matthew Wiersma

It is shown that the reduced C*-algebra of a nontrivial linear group $\Gamma<GL_{d}(k)$ with trivial amenable radical is selfless. Thus selflessness and simplicity coincide for reduced C*-algebras of linear groups. Similar results are…

Operator Algebras · Mathematics 2026-02-16 Itamar Vigdorovich

Let $P$ be a unital subsemigroup of a group $G$. We propose an approach to $\mathrm{C}^*$-algebras associated to product systems over $P$. We call the $\mathrm{C}^*$-algebra of a given product system $\mathcal{E}$ its covariance algebra and…

Operator Algebras · Mathematics 2018-11-21 Camila F. Sehnem

We describe some of the forms of freeness of group actions on noncommutative C*-algebras that have been used, with emphasis on actions of finite groups. We give some indications of their strengths, weaknesses, applications, and…

Operator Algebras · Mathematics 2009-03-02 N. Christopher Phillips

We describe a proof of the following folklore theorem: If $\cX = G/K$ is the homogeneous space of a simply connected compact semisimple Lie group with Poisson-Lie stabilizers, then the $q$-deformed algebras of regular functions $\CC[\cX_q]$…

Quantum Algebra · Mathematics 2024-09-11 Robert Yuncken

It is easy to see that every character (i.e. unital *-homomorphism to the complex numbers) of a commutative unital associative *-algebra is a pure state (i.e. extreme point in the convex set of all normalized positive linear functionals).…

Functional Analysis · Mathematics 2018-04-04 Matthias Schötz

We introduce two new formulations for the notion of "quantum metric on noncommutative space". For a compact noncommutative space associated to a unital C*-algebra, our quantum metrics are elements of the spatial tensor product of the…

Operator Algebras · Mathematics 2016-06-15 Maysam Maysami Sadr

We introduce a new class of operator algebras -- tracially complete C*-algebras -- as a vehicle for transferring ideas and results between C*-algebras and their tracial von Neumann algebra completions. We obtain structure and classification…

We prove that any reduced twisted group C*-algebra of a selfless group with the rapid decay property is selfless. As an application, we show that twisted group C*-algebras of acylindrically hyperbolic groups (possibly with nontrivial finite…

Operator Algebras · Mathematics 2026-04-28 Sven Raum , Hannes Thiel , Eduard Vilalta

We introduce two nonnegative real-valued invariants for unital and stably finite C*-algebras whose minimal instances coincide with the notion of classifiability via the Elliott invariant. The first of these is defined for AH algebras, and…

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

We revisit the characterisation of modules over non-unital $C^*$-algebras analogous to modules of sections of vector bundles. A fullness condition on the associated multiplier module characterises a class of modules which closely mirror the…

K-Theory and Homology · Mathematics 2017-06-19 Adam Rennie , Aidan Sims

We compare a number of different definitions of structure algebras and TKK constructions for Jordan (super)algebras appearing in the literature. We demonstrate that, for unital superalgebras, all the definitions of the structure algebra and…

Rings and Algebras · Mathematics 2017-07-20 Sigiswald Barbier , Kevin Coulembier

In this paper we prove that several operator algebras are completely isomorphic to each other; e.g., the $C^*_\lambda(F_k)$, $k\geq 2$, the $C^*$-algebras generated by the regular left representation $\lambda:F_k\to B(\ell_2(F_k))$, are…

Functional Analysis · Mathematics 2008-02-03 Alvaro Arias

We introduce a graph theoretic property called Condition (N) for finitely separated graphs and prove that it is equivalent to both nuclearity and exactness of the associated universal tame graph C*-algebra.

Operator Algebras · Mathematics 2017-05-15 Matias Lolk

The noncommutative analog of an approximative absolute retract (AAR) is introduced, a weakly projective C*-algebra. This property sits between being residually finite dimensional and projectivity. Examples and closure properties are…

Operator Algebras · Mathematics 2014-01-14 Terry A. Loring

We introduce and study continuous fields of JB-algebras (which are real non-associate analogues of C*-algebras). In particular, we show that for the universal enveloping C*-algebra C*sub-u(B) for the JB-algebra B defined by a continuous…

Operator Algebras · Mathematics 2008-03-26 Alexander A. Katz

Let X be a path connected, compact metric space and let A be a unital separable simple nuclear Z-stable real rank zero C*-algebra. We classify all the unital *-embeddings (up to approximate unitary equivalence) of C(X) into A. Specifically,…

Operator Algebras · Mathematics 2007-09-11 P. W. Ng , Wilhelm Winter
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