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We provide a complete description of the order isomorphisms between the self-adjoint parts of $C^*$-algebras. Furthermore, we characterize such isomorphisms between general operator intervals in $AW^*$-algebras. For the description, we use…

Operator Algebras · Mathematics 2026-01-22 Youssef El Khatiri

We introduce a method to define $C^*$-algebras from $C^*$-correspondences. Our construction generalizes Cuntz-Pimsner algebras, crossed products by Hilbert $C^*$-modules, and graph algebras.

Operator Algebras · Mathematics 2007-05-23 Takeshi Katsura

In this paper, the $C^*$-algebra of the seven-dimensional un-decomposable nilpotent Lie group is characterized explicitly for the first time(see \cite{chin}). Furthermore, the topology of its spectrum is described as a preparation for the…

Operator Algebras · Mathematics 2024-10-23 Ghofrane Kardi

In this paper we explore a certain class of non-selfadjoint operators acting in a complex separable Hilbert space. We consider a perturbation of a non-selfadjoint operator by an operator that is also non-selfadjoint. Our consideration is…

Functional Analysis · Mathematics 2019-03-26 M. V. Kukushkin

This research notes is intended to provide a quick introduction to the subject. We expose a K-theoretic approach to study group C*-algebras: started in the elementary part, with one example of description of the structure of C*-algebras of…

K-Theory and Homology · Mathematics 2014-06-09 Do Ngoc Diep

We show a general decomposition theorem in Baer *-rings. As a consequence the vast majority of decompositions known in the algebra of bounded Hilbert space operators are generalized to Baer *-rings. There are also results which are new in…

Rings and Algebras · Mathematics 2019-09-06 Zbigniew Burdak , Marek Kosiek , Patryk Pagacz , Marek Słociński

A C*-algebra is determined to a great extent by the partial order of its commutative C*-algebras. We study order-theoretic properties of this dcpo. Many properties coincide: the dcpo is, equivalently, algebraic, continuous, meet-continuous,…

Operator Algebras · Mathematics 2020-12-03 Chris Heunen , Bert Lindenhovius

In this paper we construct the spectral expansion for the non-self-adjoint differential operators generated in the space of vektor functions by the ordinary differential expression of arbitrary order with the periodic matrix coefficients by…

Spectral Theory · Mathematics 2021-12-24 O. A. Veliev

Space-time multivectors in Clifford algebra (space-time algebra) and their application to nonlinear electrodynamics are considered. Functional product and infinitesimal operators for translation and rotation groups are introduced, where…

High Energy Physics - Theory · Physics 2007-05-23 Alexander A. Chernitskii

We obtained a "decomposition scheme" of C*-algebras. We show that the classes of discrete C*-algebras (as defined by Peligard and Zsido), type II C*-algebras and type III C*-algebras (both defined by Cuntz and Pedersen) form a good…

Operator Algebras · Mathematics 2016-09-29 Chi-Keung Ng , Ngai-Ching Wong

Let $R$ be a rational function. The iterations $(R^n)_n$ of $R$ gives a complex dynamical system on the Riemann sphere. We associate a $C^*$-algebra and study a relation between the $C^*$-algebra and the original complex dynamical system.…

Operator Algebras · Mathematics 2012-09-06 Tsuyoshi Kajiwara , Yasuo Watatani

We give a classification result for a certain class of $C^{*}$-algebras $\mathfrak{A}$ over a finite topological space $X$ in which there exists an open set $U$ of $X$ such that $U$ separates the finite and infinite subquotients of…

Operator Algebras · Mathematics 2015-05-28 Soren Eilers , Gunnar Restorff , Efren Ruiz

Starting with a $W^{*}$-algebra $M$ we use the inverse system obtained by cutting down $M$ by its (central) projections to define an inverse limit of $W^{*}$-algebras, and show that how this pro-$W^{*}$-algebra encodes the local structure…

Operator Algebras · Mathematics 2007-05-23 Massoud Amini

We realize Kellendonk'?s C*-algebra of an aperiodic tiling as the tight C*-algebra of the inverse semigroup associated to the tiling, thus providing further evidence that the tight C*-algebra is a good candidate to be the natural…

Operator Algebras · Mathematics 2011-06-23 Ruy Exel , Daniel Gonçalves , Charles Starling

The (abstract) Cuntz algebra is generated by non-unitary isometries and has therefore no intrinsic finiteness properties. To approximate the elements of the Cuntz algebra by finite-dimensional objects, we thus consider a spatial…

Operator Algebras · Mathematics 2008-11-20 Steffen Roch

Results of Haagerup and Schultz (2009) about existence of invariant subspaces that decompose the Brown measure are extended to a large class of unbounded operators affiliated to a tracial von Neumann algebra. These subspaces are used to…

Operator Algebras · Mathematics 2015-09-14 Ken Dykema , Fedor Sukochev , Dmitriy Zanin

We show that the spectral theorem -- which we understand to be a statement that every self-adjoint matrix admits a certain type of canonical form under unitary similarity -- admits analogues over other $*$-algebras distinct from the complex…

Rings and Algebras · Mathematics 2023-01-25 Ran Gutin

We construct spectral triples on C*-algebraic extensions of unital C*-algebras by stable ideals satisfying a certain Toeplitz type property using given spectral triples on the quotient and ideal. Our construction behaves well with respect…

Operator Algebras · Mathematics 2016-08-29 Andrew Hawkins , Joachim Zacharias

In this work we construct a C*-algebra from an injective endomorphisms of some group G, allowing the endomorphism to have infinite cokernel. We generalize results obtained by I. Hirshberg and also by J. Cuntz and A. Vershik. In good cases…

Functional Analysis · Mathematics 2018-03-13 Felipe Vieira

In this paper we extend the traditional framework of noncommutative geometry in order to deal with spectral truncations of geometric spaces (i.e. imposing an ultraviolet cutoff in momentum space) and with tolerance relations which provide a…

Quantum Algebra · Mathematics 2020-08-26 Alain Connes , Walter D. van Suijlekom
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