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We show that for every "locally finite" unit-preserving completely positive map P acting on a C*-algebra, there is a corresponding *-automorphism \alpha of another unital C*-algebra such that the two sequences P, P^2,P^3,... and \alpha,…

Operator Algebras · Mathematics 2007-05-23 William Arveson

We prove an analogue of Voiculescu's theorem: Relative bicommutant of a separable unital subalgebra $A$ of an ultraproduct of simple unital C*-algebras is equal to $A$.

Operator Algebras · Mathematics 2017-04-19 Ilijas Farah

The notion of completely positive invariant conjugate-bilinear map in a partial *-algebra is introduced and a generalized Stinespring theorem is proven. Applications to the existence of integrable extensions of *-representations of…

Mathematical Physics · Physics 2009-04-07 F. Bagarello , A. Inoue , C. Trapani

When S is a discrete subsemigroup of a discrete group G such that G = S^{-1} S, it is possible to extend circle-valued multipliers from S to G; to dilate (projective) isometric representations of S to (projective) unitary representations of…

Operator Algebras · Mathematics 2007-05-23 Marcelo Laca

Given a graph of C*-algebras, we prove a long exact sequence in KK-theory for both the maximal and the vertex-reduced fundamental C*-algebras in the presence of possibly non GNS-faithful conditional expectations. We deduce from it the…

Operator Algebras · Mathematics 2016-12-28 Fima Pierre , Germain Emmanuel

We characterize the canonical diagonal subalgebra of the C*-algebra associated with a generalized Boolean dynamical system. We also introduce a particular commutative subalgebra, which we call the abelian core, in our C*-algebra. We then…

Operator Algebras · Mathematics 2023-11-08 Eun Ji Kang

We prove in an elementary fashion that the image of a commutative monotone $\sigma$-complete $C^*$-algebra under a $\sigma$-normal morphism is again monotone $\sigma$-complete and give an application of this result in spectral theory.

Operator Algebras · Mathematics 2007-10-15 Marcel de Jeu

We obtain a fundamental inequality for a contraction with respect to a $C^*$-algebra valued metric space. As an application of this inequality a simple proof is given for the fixed point theorem in $C^*$-algebra valued metric space.

Functional Analysis · Mathematics 2017-08-15 Harsh Trivedi

Let $A$ be a separable amenable $C^*$-algebra and $B$ a non-unital and $\sigma$-unital simple $C^*$-algebra with continuous scale ($B$ need not be stable). We classify, up to unitary equivalence, all essential extensions of the form $0…

Operator Algebras · Mathematics 2023-07-31 James Gabe , Huaxin Lin , Ping Wong Ng

The universal C*-algebra generated by n projections has been described. As an immediate corollary one obtains structure theorem for a pair of projections and the solution to an associated index problem. This puts the study of a pair of…

Operator Algebras · Mathematics 2007-05-23 Partha Sarathi Chakraborty

In this paper, we generalize the existence result in [14] and prove convergence theorems of the iterative scheme in [12, 16] for monotone generalized alpa-nonexpansive mappings in uniformly convex partially ordered hyperbolic metric spaces.…

Functional Analysis · Mathematics 2020-06-29 Chang Il Rim , Jong Gyong Kim , Chol-Hui Yun

We prove simplicity and pure infiniteness results for a certain class of labelled graph $C^*$-algebras. We show, by example, that this class of unital labelled graph $C^*$-algebras is strictly larger than the class of unital graph…

Operator Algebras · Mathematics 2008-01-15 T. Bates , D. A. Pask

We continue our study of the general theory of possibly nonselfadjoint algebras of operators on a Hilbert space, and modules over such algebras, developing a little more technology to connect `nonselfadjoint operator algebra' with the…

Operator Algebras · Mathematics 2007-05-23 David P. Blecher

Main result: If a C*-algebra is simple, $\sigma$-unital, has finitely many extremal traces, and has strict comparison of positive elements by traces, then its multiplier also has strict comparison of positive elements by traces. The same…

Operator Algebras · Mathematics 2015-01-23 Victor Kaftal , Ping Ng , Shuang Zhang

For a finitely aligned k-graph $\Lambda$ with X a set of vertices in $\Lambda$ we define a universal C*-algebra called $C^*(\Lambda,X)$ generated by partial isometries. We show that $C^*(\Lambda,X)$ is isomorphic to the corner…

Operator Algebras · Mathematics 2007-05-23 Stephen Allen

For $ C^*$-algebras $ \mathfrak{A}, A$ and $ B $ where $ A $ and $ B $ are $ \mathfrak{A} $-bimodules with compatible actions, we consider amalgamated $ \mathfrak{A} $-module tensor product of $ A $ and $ B $ and study its relation with the…

Operator Algebras · Mathematics 2024-08-06 Ahmad Shirinkalam

We provide a self-contained proof of the Artin-Wedderburn theorem in the case of finite-dimensional Von Neumann algebras (or equivalently unital C* algebras) that is fully constructive and uses only basic notions of linear algebra.

Rings and Algebras · Mathematics 2025-07-15 Octave Mestoudjian , Pablo Arrighi

We develop elements of a general dilation theory for operator-valued measures and bounded linear maps between operator algebras that are not necessarily completely-bounded. We prove our main results by extending and generalizing some known…

Operator Algebras · Mathematics 2012-07-23 Deguang Han , David R. Larson , Bei Liu , Rui Liu

We present some properties of (not necessarily linear) positive maps between $C^*$-algebras. We first extend the notion of Lieb functions to that of Lieb positive maps between $C^*$-algebras. Then we give some basic properties and…

Operator Algebras · Mathematics 2021-07-23 Ali Dadkhah , Mox Sal Moslehian

In this paper, we give a form of refined Roth's theorem. As an application, we prove a special case of the $abc$-conjecture.

Number Theory · Mathematics 2024-08-02 Pei-Chu Hu , Bao Qin Li
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