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Related papers: C*-Rhapsody

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In the present paper we study the structure of C*-$algebras generated by a certain *-algebra A and a partial isometry inducing an endomorphism of A.

Operator Algebras · Mathematics 2007-05-23 A. Lebedev , A. Odzijewicz

We use non-symmetric distances to give a self-contained account of C*-algebra filters and their corresponding compact projections, simultaneously simplifying and extending their general theory.

Operator Algebras · Mathematics 2019-11-19 Tristan Bice , Alessandro Vignati

Examples of operator algebras with involution include the operator $*$-algebras occurring in noncommutative differential geometry studied recently by Mesland, Kaad, Lesch, and others, several classical function algebras, triangular matrix…

Operator Algebras · Mathematics 2019-02-20 David P. Blecher , Zhenhua Wang

This paper is devoted to the horizontal (``characteristic'') cohomology of systems of differential equations. Recent results on computing the horizontal cohomology via the compatibility complex are generalized. New results on the Vinogradov…

Differential Geometry · Mathematics 2007-05-23 Alexander Verbovetsky

In this paper, we present a captivating construction by Grothendieck, originally formulated for algebraic varieties, and adapt it to the realm of C*-algebras. Our main objective is to investigate the conditions under which this particular…

Operator Algebras · Mathematics 2023-07-31 E. Ghamari , C. Ingalls , D. Kucerovsky

We study cohomology theories of strongly homotopy algebras, namely $A_\infty, C_\infty$ and $L_\infty$-algebras and establish the Hodge decomposition of Hochschild and cyclic cohomology of $C_\infty$-algebras thus generalising previous work…

Quantum Algebra · Mathematics 2007-05-23 Alastair Hamilton , Andrey Lazarev

We define and examine sequentially split $*$-homomorphisms between $\mathrm{C}^*$-algebras and $\mathrm{C}^*$-dynamical systems. For a $*$-homomorphism, the property of being sequentially split can be regarded as an approximate weakening of…

Operator Algebras · Mathematics 2018-01-12 Selçuk Barlak , Gábor Szabó

For elements $a, b$ of a C*-algebra we denote $a=ab$ by $a\ll b$. We show that all $\omega_1$-unital C*-algebras have $\ll$-increasing approximate units, extending a classical result for $\sigma$-unital C*-algebras. We also construct (in…

Operator Algebras · Mathematics 2019-11-19 Tristan Bice , Piotr Koszmider

A universal C*-algebra of the electromagnetic field is constructed. It is represented in any quantum field theory which incorporates electromagnetism and expresses basic features of this field such as Maxwell's equations, Poincar\'e…

Mathematical Physics · Physics 2015-10-20 Detlev Buchholz , Fabio Ciolli , Giuseppe Ruzzi , Ezio Vasselli

The paper studies the harmonic maps on a direction between a Riemannian space and a generalized Lagrange space. Also, it is proved there that the solutions of C^2 class of certain ODEs or PDEs are harmonic maps, in the sense of this paper.

Differential Geometry · Mathematics 2010-07-27 Mircea Neagu

In this paper, we study $C^*$-envelopes of finite-dimensional operator algebras arising from constrained interpolation problems on the unit disc. In particular, we consider interpolation problems for the algebra $H^\infty_{\text{node}}$…

Operator Algebras · Mathematics 2025-08-19 Gal Ben Ayun , Eli Shamovich

It is shown that every linear strong Birkhoff-James isomorphism between unital $C^*$-algebras is a $*$-isomorphism followed by a unitary multiplication. Moreover, as a partial extension of this result to the non-unital case, the form of…

Operator Algebras · Mathematics 2025-10-29 Bojan Kuzma , Srdjan Stefanović , Ryotaro Tanaka

We introduce new formulations of aperiodicity and cofinality for finitely aligned higher-rank graphs \Lambda, and prove that C*(\Lambda) is simple if and only if \Lambda is aperiodic and cofinal. The main advantage of our versions of…

Operator Algebras · Mathematics 2015-05-13 Peter Lewin , Aidan Sims

This paper investigates and classifies a specific class of one-parameter continuous fields of C*-algebras, which can be seen as generalized AI-algebras. Building on the classification of *-homomorphisms between interval algebras by the…

Operator Algebras · Mathematics 2026-01-08 Laurent Cantier

To an $r$-dimensional subshift of finite type satisfying certain special properties we associate a $C^*$-algebra $\cA$. This algebra is a higher rank version of a Cuntz-Krieger algebra. In particular, it is simple, purely infinite and…

Operator Algebras · Mathematics 2013-02-25 Guyan Robertson , Tim Steger

A host algebra of a topological group G is a C^*-algebra whose representations are in one-to-one correspondence with certain continuous unitary representations of G. In this paper we present an approach to host algebras for infinite…

Operator Algebras · Mathematics 2007-09-10 Karl-Hermann Neeb

The action on the trace space induced by a generic automorphism of a suitable finite classifiable C*-algebra is shown to be chaotic and weakly mixing. Model C*-algebras are constructed to observe the central limit theorem and other…

Operator Algebras · Mathematics 2023-05-08 Bhishan Jacelon

This is a brief survey of some recent developments in the study of infinite dimensional Hopf algebras which are either noetherian or have finite Gelfand-Kirillov dimension. A number of open questions are listed.

Rings and Algebras · Mathematics 2014-05-19 Ken A. Brown , Paul Gilmartin

We look at various forms of spectrum and associated pseudospectrum that can be defined for noncommuting $d$-tuples of Hermitian elements of a $C^*$-algebra. The emphasis is on theoretical calculations of examples, in particular for…

Operator Algebras · Mathematics 2024-03-08 Alexander Cerjan , Vasile Lauric , Terry A. Loring

We prove some stability results for certain classes of C*-algebras. We prove that whenever $A$ is a finite-dimensional C*-algebra, $B$ is a C*-algebra and $\phi\colon A\to B$ is approximately a $^*$-homomorphism then there is an actual…

Operator Algebras · Mathematics 2016-07-04 Paul McKenney , Alessandro Vignati