English
Related papers

Related papers: C*-algebras generated by multiplication operators …

200 papers

We compare two C*-algebras that have been used to study the essential spectrum. This is done by considering a simple second order elliptic differential operator acting in L^2(R^N), which is affiliated with one or both of the algebras…

Spectral Theory · Mathematics 2012-01-12 E Brian Davies , Vladimir Georgescu

Given a compact space X and two commuting continuous open surjective maps sigma_1, sigma_2 : X --> X, we construct certain C*-algebras that reflect the dynamics of the N^2-action. When the maps sigma_1, sigma_2 are local homeomorphisms,…

Operator Algebras · Mathematics 2007-05-23 Valentin Deaconu

In previous articles, a magnetic pseudodifferential calculus and a family of C*-algebras associated with twisted dynamical systems were introduced and the connections between them have been established. We extend this formalism to symbol…

Mathematical Physics · Physics 2011-01-11 Max Lein , M. Mantoiu , S. Richard

Let $\cal M$ be a Banach C*-module over a C*-algebra $A$ carrying two $A$-valued inner products $< .,. >_1$, $<.,. >_2$ which induce equivalent to the given one norms on $\cal M$. Then the appropriate unital C*-algebras of adjointable…

funct-an · Mathematics 2025-05-08 Michael Frank

We study the elementary C*-algebra whose elements are the sum of a diagonal plus a compact operator. We describe the structure of the unitary group, the sets of ideals, automorhisms and projections.

Operator Algebras · Mathematics 2019-03-15 Esteban Andruchow , Eduardo Chiumiento , Alejandro Varela

This paper contains a quite detailed description of the C*-algebra arising from the transformation groupoid of a rational map of degree at least two on the Riemann sphere. The algebra is decomposed stepwise via extensions of familiar…

Operator Algebras · Mathematics 2012-02-14 Klaus Thomsen

We show that a unital ring is generated by its commutators as an ideal if and only if there exists a natural number $N$ such that every element is a sum of $N$ products of pairs of commutators. We show that one can take $N \leq 2$ for…

Rings and Algebras · Mathematics 2024-04-04 Eusebio Gardella , Hannes Thiel

We compute the K-theory of the three C*-algebras associated to a rational function R acting on the Riemann sphere, its Fatou set, and its Julia set. The latter C*-algebra is a unital UCT Kirchberg algebra and is thus classified by its…

K-Theory and Homology · Mathematics 2023-07-26 Jeremy B. Hume

Let $L$ be a length function on a group $G$, and let $M_L$ denote the operator of pointwise multiplication by $L$ on $\ell^2(G)$. Following Connes, $M_L$ can be used as a "Dirac" operator for the reduced group C*-algebra $C_r^*(G)$. It…

Operator Algebras · Mathematics 2019-08-15 Michael Christ , Marc A. Rieffel

We show that certain C*-algebras which have been studied among others by Arzumanian, Vershik, Deaconu, and Renault in connection to a measure preserving transformation of a measure space and/or to a covering map of a compact space are…

Operator Algebras · Mathematics 2007-05-23 R. Exel , A. Vershik

Let R be a finite Blaschke product. We study the C*-algebra TC_R generated by both the composition operator C_R and the Toeplitz operator T_z on the Hardy space. We show that the simplicity of the quotient algebra OC_R by the ideal of the…

Operator Algebras · Mathematics 2011-10-21 Hiroyasu Hamada

Cuntz and Li have defined a C*-algebra associated to any integral domain, using generators and relations, and proved that it is simple and purely infinite and that it is stably isomorphic to a crossed product of a commutative C*-algebra. We…

Operator Algebras · Mathematics 2011-08-29 S. Kaliszewski , M. Landstad , John Quigg

We begin the systematic model theoretic study of $\mathrm{C}^*$-algebras using the tools of continuous logic.

Logic · Mathematics 2018-04-17 I. Farah , B. Hart , M. Lupini , L. Robert , A. Tikuisis , A. Vignati , W. Winter

We study the C$^*$ algebra generated by the composition operator $C_a$ acting on the Hardy space $H^2$ of the unit disk, given by $C_af=f\circ\varphi_a$, where $$ \varphi_a(z)=\frac{a-z}{1-\bar{a}z}, $$ for $|a|<1$. Also several operators…

Operator Algebras · Mathematics 2025-04-22 Esteban Andruchow

We present an explicit formula for the $K$-theory of the $C^*$-algebra associated with a relative generalized Boolean dynamical system $(\CB, \CL, \theta, \CI_\af; \CJ)$. In particular, we find concrete generators for the $K_1$-group of…

Operator Algebras · Mathematics 2025-09-17 Toke Meier Carlsen , Eun Ji Kang

We introduce algebraic dynamical systems, which consist of an action of a right LCM semigroup by injective endomorphisms of a group. To each algebraic dynamical system we associate a C*-algebra and describe it as a semigroup C*-algebra. As…

Operator Algebras · Mathematics 2019-02-08 Nathan Brownlowe , Nadia S. Larsen , Nicolai Stammeier

This paper surveys the recent advances in the interactions between symbolic dynamics and C*-algebras. We explain how conjugacies and orbit equivalences of both two-sided (invertible) and one-sided (noninvertible) symbolic systems may be…

Operator Algebras · Mathematics 2023-07-18 Kevin Aguyar Brix

Enveloping $C^*$-algebras for some finitely generated $*$-algebras are considered. It is shown that all of the considered algebras are identically defined by their dual spaces. The description in terms of matrix-functions is given. Keywords…

Operator Algebras · Mathematics 2011-01-27 Yurii Savchuk

We show that the following operator algebras have hyperarithmetic theory: the hyperfinite II$_1$ factor $\mathcal R$, $L(\Gamma)$ for $\Gamma$ a finitely generated group with solvable word problem, $C^*(\Gamma)$ for $\Gamma$ a finitely…

Operator Algebras · Mathematics 2020-06-11 Isaac Goldbring , Bradd Hart

This is a survey of work in which the author was involved in recent years. We consider C*-algebras constructed from representations of one or several algebraic endomorphisms of a compact abelian group - or, dually, of a discrete abelian…

Operator Algebras · Mathematics 2015-12-04 Joachim Cuntz