English
Related papers

Related papers: Boundary Representations for Operator Algebras

200 papers

We construct some inverse-closed algebras of bounded integral operators with operator-valued kernels, acting in spaces of vector-valued functions on locally compact groups. To this end we make systematic use of covariance algebras…

Functional Analysis · Mathematics 2014-08-21 Ingrid Beltita , Daniel Beltita

We exhibit a singly generated, semisimple commutative operator algebra with a contractive approximate identity, such that the spectrum of the generator is a null sequence and zero, but the algebra is not the closed linear span of the…

Operator Algebras · Mathematics 2014-10-28 David P. Blecher , Charles John Read

Multidimensional contractions of irreducible representations of Cayley--Klein orthogonal algebras in Gel'fand--Zetlin basis are considered. Contracted over different parameters, algebras can turn out to be isomorphic. In this case method of…

Mathematical Physics · Physics 2007-05-23 N. A. Gromov , S. S. Moskaliuk

We obtain a characterization of the unital C*-algebras with the property that every element is a limit of products of positive elements, thereby answering a question of Murphy and Phillips.

Operator Algebras · Mathematics 2021-03-30 Leonel Robert

The operator algebras of a new family of relativistic geometric models of the relativistic oscillator are studied. It is shown that, generally, the operator of number of quanta and the pair of the shift operators of each model are the…

Mathematical Physics · Physics 2009-10-30 Ion I. Cotăescu , Gheorghe Draganescu

We consider linear bounded operators acting in Banach spaces with a basis, such operators can be represented by an infinite matrix. We prove that for an invertible operator there exists a sequence of invertible finite-dimensional operators…

Functional Analysis · Mathematics 2024-03-12 Alexander Vasilyev , Vladimir Vasilyev , Abu Bakarr Kamanda Bongay

Given a Hilbert module E over a C*-algebra A, we show that the collection of all bounded A-module operators acting on E forms the reflexive closure for the algebra of the adjointable operators. We also make an observation regarding the…

Operator Algebras · Mathematics 2015-02-03 Elias G. Katsoulis

In this paper we study the representation theory for certain ``half lattice vertex algebras.'' In particular we construct a large class of irreducible modules for these vertex algebras. We also discuss how the representation theory of these…

Quantum Algebra · Mathematics 2007-05-23 Stephen Berman , Chongying Dong , Shaobin Tan

We geometrically describe the relation induced on a set of graphs by isomorphism of their associated graph C*-algebras as the smallest equivalence relation generated by five types of moves. The graphs studied have finitely many vertices and…

Operator Algebras · Mathematics 2019-10-28 Sara E. Arklint , Søren Eilers , Efren Ruiz

The paper introduces a (universal) C*-algebra of continuous functions vanishing at infinity on the n-dimensional quantum complex space. To this end, the well-behaved Hilbert space representations of the defining relations are classified.…

Operator Algebras · Mathematics 2025-02-03 Ismael Cohen , Elmar Wagner

The representations of a $k$-graph $C^*$-algebra $C^*(\Lambda)$ which arise from $\Lambda$-semibranching function systems are closely linked to the dynamics of the $k$-graph $\Lambda$. In this paper, we undertake a systematic analysis of…

Operator Algebras · Mathematics 2021-02-09 Carla Farsi , Elizabeth Gillaspy , Daniel Gonçalves

In this article we give a short and informal overview of some aspects of the theory of C*- and von Neumann algebras. We also mention some classical results and applications of these families of operator algebras.

Operator Algebras · Mathematics 2013-04-12 Fernando Lledó

The well-behaved representations of the coordinate algebra of a 2-dimensional quantum complex plane are classified and a C*-algebra is defined which can be viewed as the algebra of continuous functions on the 2-dimensional quantum complex…

Quantum Algebra · Mathematics 2018-02-20 Ismael Cohen , Elmar Wagner

We transfer the theory of slack operators and sums-of-squares-criteria for lifts from convex cones to operator systems. These allow to study the following question, among others: Given an abstract operator system, is its enveloping…

Operator Algebras · Mathematics 2025-08-22 Markus Dannemüller , Tim Netzer

Using a binary representation for basis elements of an algebra combined with a framework of multiplier and index functions, a connection has been established between the structure of a large class of algebras and the XOR componentwise…

Mathematical Physics · Physics 2025-09-30 Derek Courchesne , Sébastien Tremblay

We write arbitrary separable nuclear C*-algebras as limits of inductive systems of finite-dimensional C*-algebras with completely positive connecting maps. The characteristic feature of such CPC*-systems is that the maps become more and…

Operator Algebras · Mathematics 2024-10-10 Kristin Courtney , Wilhelm Winter

It is shown how a C*-algebra representation of the transformations of a physical system can be derived from two operational postulates: 1) the existence of dynamically independent systems}; 2) the existence of symmetric faithful states.…

Quantum Physics · Physics 2007-10-09 Giacomo Mauro D'Ariano

We investigate representations of *-algebras associated with posets. Unitarizable representations of the corresponding (bound) quivers (which are polystable representations for some appropriately chosen slope function) give rise to…

Representation Theory · Mathematics 2012-07-12 Thorsten Weist , Kostyantyn Yusenko

In this note we describe the recent progress in the classification of bounded and semibounded representations of infinite dimensional Lie groups. We start with a discussion of the semiboundedness condition and how the new concept of a…

Representation Theory · Mathematics 2015-10-30 Karl-Hermann Neeb

Given any irreducible inclusion $\mB \subset \mA$ of unital $C^*$-algebras with a finite-index conditional expectation $E: \mA \to \mB$, we show that the set of $E$-compatible intermediate $C^*$-subalgebras is finite, thereby generalizing a…

Operator Algebras · Mathematics 2026-01-01 Ved Prakash Gupta , Sumit Kumar