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We introduce a topology on the ideal space of inductive limits of C*-algebras built by a topological inverse limit of the Fell topologies on the C*-algebras of the given inductive sequence and we produce conditions for when this topology…

Operator Algebras · Mathematics 2018-02-23 Konrad Aguilar

This paper constructs the geometrically natural objects which are associated with any projection tensor field on a manifold with any affine connection. The approaches to projection tensor fields which have been used in general relativity…

General Relativity and Quantum Cosmology · Physics 2009-10-22 Robert H. Gowdy

The generalized state space of a commutative C*-algebra, denoted S_H(C(X)), is the set of positive unital maps from C(X) to the algebra B(H) of bounded linear operators on a Hilbert space H. C*-convexity is one of several non-commutative…

Operator Algebras · Mathematics 2009-02-12 M. C. Gregg

Let H be a full Hilbert bimodule over a C*-algebra A. We show that the Cuntz-Pimsner C*-algebra associated to H is exact if and only if A is exact. Using this result, we give alternative proofs for exactness of reduced amalgamated free…

Operator Algebras · Mathematics 2007-05-23 Ken Dykema , Dimitri Shlyakhtenko

Let $\mathcal{A}$ be a commutative $AW^*$-algebra, let $S(\mathcal{A})$ be the *-algebra of all measurable operators affiliated with $\mathcal{A}$, let $\mathcal{I}$ be an ideal in $\mathcal{A}$, let $s(\mathcal{I})$ be the support of the…

Operator Algebras · Mathematics 2012-08-27 V. I. Chilin , G. B. Levitina

Let $A=(A_x)$ be a (semi-)continuous field of $C^*$-algebras over a compact Hausdorff space $X$ and let $p=(p_x)$ be a projection in $A$ such that each $p_x\in A_x$ is properly infinite ($x\in X$). Then $p$ is properly infinite if the field…

Operator Algebras · Mathematics 2007-05-23 Etienne Blanchard

The purpose of this paper is two-fold: firstly, we give a characterization on the level of non-unital operator systems for when the zero map is a boundary representation. As a consequence, we show that a non-unital operator system arising…

Operator Algebras · Mathematics 2024-08-13 Se-Jin Kim

We introduce completely bounded kernels taking values in L(A,B) where A and B are C*-algebras. We show that if B is injective such kernels have a Kolmogorov decomposition precisely when they can be scaled to be completely contractive, and…

Operator Algebras · Mathematics 2012-12-17 Tirthankar Bhattacharyya , Michael A. Dritschel , Christopher S. Todd

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

Given a finite tensor category $\ca$, an exact indecomposable $\ca$-module category $\Mo$, and a tensor subcategory $\Do\subseteq \ca^*_\Mo$, we describe a way to produce \textit{exact} commutative algebras in the center $Z(\ca)$, measuring…

Quantum Algebra · Mathematics 2022-12-15 Martín Mombelli

In the first part of this paper we study a best approximation of a vector in Euclidean space R^n with respect to a closed semi-algebraic set C and a given semi-algebraic norm. Assuming that the given norm and its dual norm are…

Algebraic Geometry · Mathematics 2013-11-08 Shmuel Friedland , Malgorzata Stawiska

Approximate morphisms have seen significant study across many areas of mathematics, for instance, in the theory of Absolute (Neighborhood) Retracts in topology, or of almost-commuting unitary matrices in analysis. This paper initiates study…

Operator Algebras · Mathematics 2026-01-14 Samantha Pilgrim

We study semiprojective, subhomogeneous C*-algebras and give a detailed description of their structure. In particular, we find two characterizations of semiprojectivity for subhomogeneous C*-algebras: one in terms of their primitive ideal…

Operator Algebras · Mathematics 2017-01-03 Dominic Enders

Consider strong approximation for algebraic varieties defined over a number field $k$. Let $S$ be a finite set of places of $k$ containing all archimedean places. Let $E$ be an elliptic curve of positive Mordell-Weil rank and let $A$ be an…

Number Theory · Mathematics 2019-01-09 Yongqi Liang

Let $Y\subset{\mathbb R}^n$ be a triangulable set and let $r$ be either a positive integer or $r=\infty$. We say that $Y$ is a $\mathscr{C}^r$-approximation target space, or a $\mathscr{C}^r\text{-}\mathtt{ats}$ for short, if it has the…

Differential Geometry · Mathematics 2021-03-23 José F. Fernando , Riccardo Ghiloni

This work is devoted to establish the strong convergence results of an iterative algorithm generated by the shrinking projection method in Hilbert spaces. The proposed approximation sequence is used to find a common element in the set of…

Functional Analysis · Mathematics 2018-03-07 Abdul Ghaffar , Zafar Ullah , Muhammad Aqeel Ahmad Khan , Faisal Mumtaz

The induction and reduction precesses of an O*-vector space $\M$ obtained by means of a projection taken, respectively, in $\M$ itself or in its weak bounded commutant $\M'_\w$ are studied. In the case where $\M$ is a partial GW*-algebra,…

Mathematical Physics · Physics 2012-07-10 Fabio Bagarello , Atsushi Inoue , Camillo Trapani

An algebra $\mathcal{A}$ of $n\times n$ complex matrices is said to be \textit{idempotent compressible} if $E\mathcal{A}E$ is an algebra for all idempotents $E\in\mathbb{M}_n(\mathbb{C})$. Analogously, $\mathcal{A}$ is said to be…

Rings and Algebras · Mathematics 2021-06-22 Zachary Cramer , Laurent W. Marcoux , Heydar Radjavi

Let X be an infinite, compact, metrizable space of finite covering dimension and h a minimal homeomorphism of X. We prove that the crossed product of C(X) by h absorbs the Jiang-Su algebra tensorially and has finite nuclear dimension. As a…

Operator Algebras · Mathematics 2009-03-25 Andrew S. Toms , Wilhelm Winter

We study the convergence of specific inexact alternating projections for two non-convex sets in a Euclidean space. The $\sigma$-quasioptimal metric projection ($\sigma \geq 1$) of a point $x$ onto a set $A$ consists of points in $A$ the…

Optimization and Control · Mathematics 2025-09-09 Stanislav Budzinskiy