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We consider the behaviour of holomorphic functions on a bounded open subset of the plane, satisfying a Lipschitz condition with exponent $\alpha$, with $0<\alpha<1$, in the vicinity of an exceptional boundary point where all such functions…

Complex Variables · Mathematics 2015-09-29 Anthony G. O'Farrell

We show that a separable purely infinite C*-algebra is of real rank zero if and only if its primitive ideal space has a basis consisting of compact-open sets and the natural map K_0(I) -> K_0(I/J) is surjective for all closed two-sided…

Operator Algebras · Mathematics 2010-11-24 Cornel Pasnicu , Mikael Rordam

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

We obtain a Galois correspondence between the lattice of intermediate C*-discrete subalgebras intermediate to a given irreducible C*-discrete inclusion, and characterize these as targets of compatible expectations under a traciality…

Operator Algebras · Mathematics 2026-05-29 Roberto Hernández Palomares , Brent Nelson

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 note we extend the construction of a $C^*$-algebra associated to a self-similar graph to the case of arbitrary countable graphs. We reduce the problem to the row-finite case with no sources, by using a desingularization process.…

Operator Algebras · Mathematics 2018-07-05 Ruy Exel , Enrique Pardo , Charles Starling

Suppose that $\mathcal M$ is a countably decomposable type II$_1$ von Neumann algebra and $\mathcal A$ is a separable, non-nuclear, unital C$^*$-algebra. We show that, if $\mathcal M$ has Property $\Gamma$, then the similarity degree of…

Operator Algebras · Mathematics 2015-08-25 Wenhua Qian , Junhao Shen

The question of which separable C*-algebras have abelian central sequence algebras was raised and studied by Phillips ([Ph88]) and Ando-Kirchberg ([AK14]). In this paper we give a complete answer to their question: A separable C*-algebra…

Operator Algebras · Mathematics 2022-04-08 Dominic Enders , Tatiana Shulman

We show that every proper, dense ideal in a C*-algebra is contained in a prime ideal. It follows that a subset generates a C*-algebra as a not necessarily closed ideal if and only if it is not contained in any prime ideal. This allows us to…

Operator Algebras · Mathematics 2023-08-11 Eusebio Gardella , Hannes Thiel

We obtain a description of the C*-algebras which can occur as a simple quotient of the C*-algebra of a locally injective surjection on a compact metric space of finite covering dimension.

Operator Algebras · Mathematics 2014-10-10 Toke Meier Carlsen , Klaus Thomsen

We consider operators on $L^2$ spaces that expand the support of vectors in a manner controlled by some constraint function. The primary objects of study are $\mathrm C^*$-algebras that arise from suitable families of constraints, which we…

Operator Algebras · Mathematics 2022-11-08 Bruno de Mendonça Braga , Joseph Eisner , David Sherman

We consider inductive systems of C*-algebras with completely positive contractive connecting maps. We define a condition, called C*-encoding, which is sufficient for the limit of the system to be completely order isomorphic to a C*-algebra…

Operator Algebras · Mathematics 2023-06-26 Kristin Courtney

The class of separable C*-algebras which can be written as inductive limits of continuous-trace C*-algebras with spectrum homeomorphic to a disjoint union of trees and trees with a point removed is classified by the Cuntz semigroup.

Operator Algebras · Mathematics 2010-04-05 Alin Ciuperca , George A. Elliott , Luis Santiago

Let $A$ be a partial *-algebra endowed with a topology $\tau$ that makes it into a locally convex topological vector space $A[\tau]$. Then $A$ is called a topological partial *-algebra if it satisfies a number of conditions, which all…

Mathematical Physics · Physics 2009-04-07 J. -P. Antoine , F. Bagarello , C. Trapani

We propose a list of inequalities which characterize central elements in von Neumann algebras and C*-algebras.

Operator Algebras · Mathematics 2020-10-21 Andrej Novikov , Oleg Tikhonov

An open (resp., closed) subset A of a topological space (X, T ) is called C-open (resp., C-closed) set if cl(A) \ A (resp., A \ int(A)) is a countable set. This paper aims to present the concept of C-open and C-closed sets. We first…

General Topology · Mathematics 2023-05-08 M. H. Alqahtani

We investigate the polynomial closure operation (C -> Pol(C)) defined on classes of regular languages. We present an interesting and useful connection relating the separation problem for the class C and the membership problem for it…

Formal Languages and Automata Theory · Computer Science 2018-02-20 Thomas Place , Marc Zeitoun

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 study the extent of countable saturation for coronas of abelian C*-algebras. In particular, we show that the corona algebra of $C_0(\bbR^n)$ is countably saturated if and only if $n=1$.

Logic · Mathematics 2022-06-09 Ilijas Farah , Alessandro Vignati

Compositionality is a key property for dealing with complexity, which has been studied from many points of view in diverse fields. Particularly, the composition of individual computations (or programs) has been widely studied almost since…

Logic in Computer Science · Computer Science 2022-06-06 Damian Arellanes