English
Related papers

Related papers: Atiyah-J\"anich theorem for $\sigma$-C*-algebras

200 papers

We introduce and study a $K$-theory of twisted bundles for associative algebras $A(\mathfrak g)$ of formal series with an infinite-Lie algebra coefficients over arbitrary compact topological spaces. Fibers of such bundles are given by…

Functional Analysis · Mathematics 2022-07-08 A. Zuevsky

We define E-theory for separable C*-algebras over second countable topological spaces and establish its basic properties. This includes an approximation theorem that relates the E-theory over a general space to the E-theories over finite…

K-Theory and Homology · Mathematics 2015-10-23 Marius Dadarlat , Ralf Meyer

A families index theorem in K-theory is given for the setting of Atiyah, Patodi and Singer of a family of Dirac operators with spectral boundary condition. This result is deduced from such a K-theory index theorem for the calculus of cusp,…

Differential Geometry · Mathematics 2007-05-23 Richard B. Melrose , Frederic Rochon

The construction of a C*-algebra of a differential groupoid is presented. It is shown that it defines a covariant functor from the category of differential groupoids in a sense of S. Zakrzewski to the category of C*-algebras.

Quantum Algebra · Mathematics 2007-05-23 Piotr Stachura

Algebras of functions on quantum weighted projective spaces are introduced, and the structure of quantum weighted projective lines or quantum teardrops are described in detail. In particular the presentation of the coordinate algebra of the…

Quantum Algebra · Mathematics 2015-05-28 Tomasz Brzeziński , Simon A. Fairfax

Under mild assumptions, we characterise modules with projective resolutions of length n in the target category of filtrated K-theory over a finite topological space in terms of two conditions involving certain Tor-groups. We show that the…

Operator Algebras · Mathematics 2014-02-11 Rasmus Bentmann

We prove a strong classification result for a certain class of $C^{*}$-algebras with primitive ideal space $\widetilde{\mathbb{N}}$, where $\widetilde{\mathbb{N}}$ is the one-point compactification of $\mathbb{N}$. This class contains the…

Operator Algebras · Mathematics 2013-11-13 James Gabe , Efren Ruiz

The report below describes the applications of Banach KK-theory to a conjecture of P. Baum and A. Connes about the K-theory of group $C^*$-algebras, and a new proof of the classification by Harish-Chandra, the construction by Parthasarathy…

Operator Algebras · Mathematics 2007-05-23 Vincent Lafforgue

We present unified proofs of several properties of the corona of $\sigma$-unital C*-algebras such as AA-CRISP, SAW*, being sub-$\sigma$-Stonean in the sense of Kirchberg, and the conclusion of Kasparov's Technical Theorem. Although our…

Operator Algebras · Mathematics 2012-10-18 Ilijas Farah , Bradd Hart

K-Theory for hermitian symmetric spaces of non-compact type, as developed recently by the authors, allows to put Cartan's classification into a homological perspective. We apply this method to the case of inductive limits of finite…

K-Theory and Homology · Mathematics 2016-09-23 Dennis Bohle , Wend Werner

We give a spectral theorem for unital representations of Hermitian commutative unital *-algebras by possibly unbounded operators in a pre-Hilbert space. A better result is known for the case in which the *-algebra is countably generated.

Operator Algebras · Mathematics 2024-11-13 Marco Thill

Motivated by the description of the C*-algebra of the affine automorphism group $N_{6,28}$ of the Siegel upper half-plane of degree 2 as an algebra of operator fields defined over the unitary dual $\widehat{N_{6,28}}$ of the group, we…

Operator Algebras · Mathematics 2014-01-06 Junko Inoue , Ying-Fen Lin , Jean Ludwig

We define an analytical index map and a topological index map for conical pseudomanifolds. These constructions generalize the analogous constructions used by Atiyah and Singer in the proof of their topological index theorem for a smooth,…

Operator Algebras · Mathematics 2010-05-18 Claire Debord , Jean-Marie Lescure , Victor Nistor

We introduce a new class of C^*-algebras, which is a generalization of both graph algebras and homeomorphism C^*-algebras. This class is very large and also very tractable. We prove the so-called gauge-invariant uniqueness theorem and the…

Operator Algebras · Mathematics 2007-05-23 Takeshi Katsura

Let G be a finite group. We systematically exploit general homological methods in order to reduce the computation of G-equivariant KK-theory to topological equivariant K-theory. The key observation is that the functor assigning to a…

Operator Algebras · Mathematics 2016-05-11 Ivo Dell'Ambrogio

We study universal solutions to reflection equations with a spectral parameter, so-called K-operators, within a general framework of universal K-matrices - an extended version of the approach introduced by Appel-Vlaar. Here, the input data…

Quantum Algebra · Mathematics 2026-03-31 Guillaume Lemarthe , Pascal Baseilhac , Azat M. Gainutdinov

The paper is a continuation of the authors' work in which we considered foliations formed by the maximal dimensional K-orbits ($MD_5$-foliations) of connected $MD_5$-groups such that their Lie algebras have 4-dimensional commutative derived…

K-Theory and Homology · Mathematics 2011-01-12 Le Anh Vu , Duong Quang Hoa

We determine the $K$-theory of the $C^{*}$-algebra $C(SU_{-1}(2))$ and describe its spectrum. Moreover, we exhibit a continuous $C^{*}$-bundle over $[-1,0)$ whose fibre at $q$ is isomorphic to $C(SU_{q}(2))$.

Operator Algebras · Mathematics 2015-03-06 Selcuk Barlak

Keckic and Lazovic introduced an axiomatic approach to Fredholm theory by considering Fredholm-type elements in an unital C*-algebra as a generalization of C*-Fredholm operators on the standard Hilbert C*-module introduced by Mishchenko and…

Functional Analysis · Mathematics 2023-05-23 Stefan Ivkovic

We construct uncountably many mutually nonisomorphic simple separable stably finite unital exact C$^\ast$-algebras which are not isomorphic to their opposite algebras. In particular, we prove that there are uncountably many possibilities…

Operator Algebras · Mathematics 2024-02-14 N. Christopher Phillips , Maria Grazia Viola