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Related papers: Hyperrigidity II: $R$-dilations, ideals and decomp…

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This paper examines actions of right LCM semigroups by endomorphisms of C*-algebras that encode an additional structure of the right LCM semigroup. We define contractive covariant representations for these semigroup dynamical systems and…

Operator Algebras · Mathematics 2021-10-19 Marcelo Laca , Boyu Li

We define and study large and stably large subalgebras of simple unital C*-algebras. The basic example is the orbit breaking subalgebra of a crossed product by Z, as follows. Let X be an infinite compact metric space, let h be a minimal…

Operator Algebras · Mathematics 2014-08-26 N. Christopher Phillips

We take a new look at dilation theory for nonself-adjoint operator algebras. Among the extremal (co)extensions of a representation, there is a special property of being fully extremal. This allows a refinement of some of the classical…

Operator Algebras · Mathematics 2011-09-02 Kenneth R. Davidson , Elias G. Katsoulis

We introduce the notion of locally finite decomposition rank, a structural property shared by many stably finite nuclear C*-algebras. The concept is particularly relevant for Elliott's program to classify nuclear C*-algebras by K-theory…

Operator Algebras · Mathematics 2007-05-23 Wilhelm Winter

We solve a class of lifting problems involving approximate polynomial relations (soft polynomial relations). Various associated C*-algebras are therefore projective. The technical lemma we need is a new manifestation of Akemann and…

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

We study reproducing kernel Hilbert spaces on the unit ball with the complete Nevanlinna-Pick property through the representation theory of their algebras of multipliers. We give a complete description of the representations in terms of the…

Operator Algebras · Mathematics 2020-09-23 Raphaël Clouâtre , Michael Hartz

We show that every Lie ideal in a unital, properly infinite C*-algebra is commutator equivalent to a unique two-sided ideal. It follows that the Lie ideal structure of such a C*-algebra is concisely encoded by its lattice of two-sided…

Operator Algebras · Mathematics 2025-06-16 Hannes Thiel

In Rufus Willett's and the authors paper "Bounded Derivations on Uniform Roe Algebras" we showed that all bounded derivations on a uniform Roe algebra $C^*_u(X)$ associated to a bounded geometry metric space $X$ are inner. This naturally…

Operator Algebras · Mathematics 2021-09-29 Matthew Lorentz

In this paper, we investigate *-homomorphisms between C*-algebras associated to \'etale groupoids. First, we prove that such a *-homomorphism can be described by closed invariant subsets, groupoid homomorphisms and cocycles under some…

Operator Algebras · Mathematics 2023-08-24 Fuyuta Komura

We show that if G is a discrete group which does not have the Haagerup property but does have an unbounded cocycle into a C_0 representation and if G acts on a finite von Neumann algebra B such that the inclusion B \subset (B \rtimes G) has…

Operator Algebras · Mathematics 2010-02-10 Jesse Peterson

Motivated by advances in categorical probability, we introduce non-commutative almost everywhere (a.e.) equivalence and disintegrations in the setting of C*-algebras. We show that C*-algebras (resp. W*-algebras) and a.e. equivalence classes…

Quantum Physics · Physics 2023-12-18 Arthur J. Parzygnat , Benjamin P. Russo

We show that, if A is a separable simple unital C*-algebra which absorbs the Jiang-Su algebra Z tensorially and which has real rank zero and finite decomposition rank, then A is tracially AF in the sense of Lin, without any restriction on…

Operator Algebras · Mathematics 2007-05-23 Wilhelm Winter

In this paper we consider C*-algebraic deformations a la Rieffel and show that every state of the undeformed algebra can be deformed into a state of the deformed algebra in the sense of a continuous field of states. The construction is…

Mathematical Physics · Physics 2008-11-17 Daniel Kaschek , Nikolai Neumaier , Stefan Waldmann

We show that if K is a compact spectrahedron whose set of extreme points is closed, then the operator system of continuous affine functions on K is hyperrigid in the C*-algebra C(ex(K)).

Operator Algebras · Mathematics 2026-01-23 Marcel Scherer

Using ideas due to Jean-Luc Sauvageot, we prove the existence of a continuous unital dilation of a CP$_0$-semigroup on a separable W$^*$-algebra. This paper presents the material in the author's Ph. D. thesis (arXiv.org:1304.0134.pdf) with…

Operator Algebras · Mathematics 2013-09-16 David J. Gaebler

The notion of a subproduct system, a generalization of that of a product system, is introduced. We show that there is an essentially 1 to 1 correspondence between cp-semigroups and pairs (X,T) where X is a subproduct system and T is an…

Operator Algebras · Mathematics 2010-01-28 Orr Shalit , Baruch Solel

Motivated by Cuntz-Krieger-Toeplitz systems associated to undirected graphs and representations of groupoids, we obtain a generalisation of the Sz-Nagy's Dilation Theorem for operator valued partially positive semidefinite maps on…

Operator Algebras · Mathematics 2025-11-04 Aurelian Gheondea , Bogdan Udrea

We present a classification theorem for amenable simple stably projectionless C*-algebras with generalized tracial rank one whose $K_0$ vanish on traces which satisfy the Universal Coefficient Theorem. One of them is denoted by ${\cal Z}_0$…

Operator Algebras · Mathematics 2020-04-24 Guihua Gong , Huaxin Lin

The goal of this paper is to study when uniform Roe algebras have certain $C^*$-algebraic properties in terms of the underlying space: in particular, we study properties like having stable rank one or real rank zero that are thought of as…

Operator Algebras · Mathematics 2018-01-31 Kang Li , Rufus Willett

Dilations of completely positive semigroups to endomorphism semigroups have been studied by numerous authors. Most existing dilation theorems involve a non-unital embedding, corresponding to the embedding of $B(H)$ as a corner of $B(K)$ for…

Operator Algebras · Mathematics 2013-04-02 David J. Gaebler