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We shall introduce the notions of the strong Morita equivalence for unital inclusions of unital $C^*$-algebras and conditional expectations from an equivalence bimodule onto its closed subspace with respect to conditional expectations from…

Operator Algebras · Mathematics 2016-09-28 Kazunori Kodaka , Tamotsu Teruya

The notion of bounded element of C*-inductive locally convex spaces (or C*-inductive partial *-algebras) is introduced and discussed in two ways: the first one takes into account the inductive structure provided by certain families of…

Operator Algebras · Mathematics 2013-07-29 Giorgia Bellomonte , Salvatore Di Bella , Camillo Trapani

In analogy with the C*-algebra theory, we study variants appropriate to nonselfadjoint algebras of nuclearity, the local lifting property, exactness, and the weak expectation property. In addition, we study the relationships between these…

Operator Algebras · Mathematics 2008-04-02 David P. Blecher , Benton L. Duncan

We study C*-algebras generated by two partitions of unity subject to orthogonality relations governed by a bipartite graph which we also call "bipartite graph C*-algebras". These algebras generalize at the same time the C*-algebra…

Operator Algebras · Mathematics 2025-09-03 Björn Schäfer

A partial action is associated with a normal weakly left resolving labelled space such that the crossed product and labelled space $C^*$-algebras are isomorphic. An improved characterization of simplicity for labelled space $C^*$-algebras…

Operator Algebras · Mathematics 2019-09-11 Gilles G. de Castro , Daniel W. van Wyk

A general method of investigation of the uniqueness property for $C^*$-algebra equipped with a circle gauge action is discussed. It unifies isomorphism theorems for various crossed products and Cuntz-Krieger uniqueness theorem for…

Operator Algebras · Mathematics 2014-10-10 B. K. Kwasniewski

We conjecture that a unital C$^*$-algebra is a W$^*$-algebra if and only if each of its maximal abelian self-adjoint subalgebras is a W$^*$-algebra; this is a space-free analogue of a known result due to G.K. Pedersen. Our main result is a…

Operator Algebras · Mathematics 2026-01-09 Alec Gow

In this article, we define operator algebras internal to a rigid C*-tensor category $\mathcal{C}$. A C*/W*-algebra object in $\mathcal{C}$ is an algebra object $\mathbf{A}$ in $\operatorname{ind}$-$\mathcal{C}$ whose category of free…

Operator Algebras · Mathematics 2017-09-13 Corey Jones , David Penneys

A Hilbert $C^*$-quad module of finite type has a multi structure of Hilbert $C^*$-bimodules with two finite bases. We will construct a $C^*$-algebra from a Hilbert $C^*$-quad module of finite type and prove its universality subject to…

Operator Algebras · Mathematics 2013-10-01 Kengo Matsumoto

The purpose of this note is to describe when a general complex algebraic $^*$-algebra is pre-$C^*$-normed, and to investigate their structure when the $^*$-algebras are Baer $^*$-rings in addition to algebraicity. As a main result we prove…

Operator Algebras · Mathematics 2022-04-20 Zsolt Szűcs , Balázs Takács

The Corona Factorization Property of a C*-algebra, originally defined to study extensions of C*-algebras, has turned out to say something important about intrinsic structural properties of the C*-algebra. We show in this paper that a…

Operator Algebras · Mathematics 2013-01-24 Eduard Ortega , Francesc Perera , Mikael Rordam

It is shown that the metric on the union of the sets $X$ and $Y$ defines a Hilbert $C^*$-module over the uniform Roe algebra of the space $X$ with a fixed metric $d_X$. A number of examples of such Hilbert $C^*$-modules are described.

Operator Algebras · Mathematics 2021-05-11 V. Manuilov

It is shown in this paper that two positive elements of a C*-algebra agree on all lower semicontinuous traces if and only if they are equivalent in the sense of Cuntz and Pedersen. A similar result is also obtained in the more general case…

Operator Algebras · Mathematics 2008-06-11 Leonel Robert

It is shown that every linear strong Birkhoff-James isomorphism between unital $C^*$-algebras is a $*$-isomorphism followed by a unitary multiplication. Moreover, as a partial extension of this result to the non-unital case, the form of…

Operator Algebras · Mathematics 2025-10-29 Bojan Kuzma , Srdjan Stefanović , Ryotaro Tanaka

We present a collection of questions related to the structure and classification of nuclear C*-algebras.

Operator Algebras · Mathematics 2026-05-11 Christopher Schafhauser , Aaron Tikuisis , Stuart White

We classify all essential extensions of the form $$0 \rightarrow \W \rightarrow \D \rightarrow A \rightarrow 0$$ where $\W$ is the unique separable simple C*-algebra with a unique tracial state, with finite nuclear dimension and with…

Operator Algebras · Mathematics 2020-06-02 Huaxin Lin , Ping Wong Ng

Suppose that A is a C*-algebra for which A is isomorphic to A tensor Z, where Z is the Jiang-Su algebra: a unital, simple, stably finite, separable, nuclear, infinite dimensional C*-algebra with the same Elliott invariant as the complex…

Operator Algebras · Mathematics 2010-11-24 Mikael Rordam

We study the saturation properties of several classes of $C^*$-algebras. Saturation has been shown by Farah and Hart to unify the proofs of several properties of coronas of $\sigma$-unital $C^*$-algebras; we extend their results by showing…

Logic · Mathematics 2015-10-08 Christopher J. Eagle , Alessandro Vignati

Exotic group $C^*$-algebras are $C^*$-algebras that lie between the universal and the reduced group $C^*$-algebra of a locally compact group. We consider simple Lie groups $G$ with real rank one and investigate their exotic group…

Operator Algebras · Mathematics 2022-03-30 Tim de Laat , Timo Siebenand

We define a broad class of crossed product C*-algebras of the form C(G)xG, where G is a discrete countable amenable residually finite group, and G is a profinite completion of G. We show that they are unital separable simple nuclear…

Operator Algebras · Mathematics 2013-01-22 Stefanos Orfanos