English
Related papers

Related papers: Quantitative K-theory and the K{\"u}nneth formula …

200 papers

We compute the nuclear dimension of extensions of C*-algebras involving commutative unital quotients and stable Kirchberg ideals. We identify the finite directed graphs whose C*-algebras are covered by this theorem.

Operator Algebras · Mathematics 2025-05-13 Samuel Evington , Abraham C. S. Ng , Aidan Sims , Stuart White

We examine crossed product C*-algebras associated with non-minimal free actions of countably infinite discrete abelian groups on the circle, extending the work of Putnam, Schmidt, and Skau. We obtain a large class of unital separable…

Operator Algebras · Mathematics 2026-04-21 Jamie Bell

Using the unbounded picture of analytical K-homology, we associate a well-defined K-homology class to an unbounded symmetric operator satisfying certain mild technical conditions. We also establish an ``addition formula'' for the Dirac…

K-Theory and Homology · Mathematics 2007-05-23 Hela Bettaieb , Michel Matthey , Alain Valette

Given a row-finite $k$-graph $\Lambda$ with no sources we investigate the $K$-theory of the higher rank graph $C^*$-algebra, $C^*(\Lambda)$. When $k=2$ we are able to give explicit formulae to calculate the $K$-groups of $C^*(\Lambda)$. The…

Operator Algebras · Mathematics 2007-12-18 D. Gwion Evans

Motivated by the idea that our access to the spacetime is limited by the resolution of our measuring device, we give a new description of $K$-homology with a finite resolution. G. Yu introduced a $C^*$-algebra called the localization…

K-Theory and Homology · Mathematics 2024-01-17 Ryo Toyota

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

We introduce bivariant K-theory for nonarchimedean bornological algebras over a complete discrete valuation ring $V$. This is the universal target for dagger homotopy invariant, matricially stable and excisive functors, similar to bivariant…

K-Theory and Homology · Mathematics 2023-07-06 Devarshi Mukherjee

For a quiver with weighted arrows we define gauge-theory K-theoretic W-algebra generalizing the definition of Shiraishi et al., and Frenkel and Reshetikhin. In particular, we show that the qq-character construction of gauge theory presented…

High Energy Physics - Theory · Physics 2018-05-08 Taro Kimura , Vasily Pestun

Let $\mathfrak{g}$ be a symmetrizable Kac-Moody algebra, $U_q(\mathfrak{g})$ its quantum group, and $U_q(\mathfrak{k}) \subset U_q(\mathfrak{g})$ a quantum symmetric pair subalgebra determined by a Lie algebra automorphism $\theta$. We…

Representation Theory · Mathematics 2025-11-18 Andrea Appel , Bart Vlaar

Let $K$ be a compact metric space and let $\gamma = (\gamma_1, \dots, \gamma_n)$ be a system of proper contractions on $K$. We study a C*-algebra $\mathcal{MC}_{\gamma_1, \dots, \gamma_n}$ generated by all multiplication operators by…

Operator Algebras · Mathematics 2021-11-24 Hiroyasu Hamada

Category of fibrant objects is a convenient framework to do homotopy theory, introduced and developed by Ken Brown. In this paper, we apply it to the category of C^{*}-algebras. In particular, we get a unified treatment of (ordinary)…

K-Theory and Homology · Mathematics 2013-03-11 Otgonbayar Uuye

To a graph $\Gamma$ one can associate a C^*-algebra $C^*(\Gamma)$ generated by isometries. Such $C^*$-algebras were studied recently by Crisp and Laca. They are a special case of the Toeplitz C^*-algebras $\mathcal{T}(G, P)$ associated to…

Operator Algebras · Mathematics 2007-11-07 Nikolay A. Ivanov

We compare the K-theories of symplectic quotients with respect to a compact connected Lie group and with respect to its maximal torus, and in particular we give a method for computing the former in terms of the latter. More specifically,…

Symplectic Geometry · Mathematics 2007-05-23 Megumi Harada , Gregory D. Landweber

The main objective of this paper is to propose a definition of non-connective K-theory for a wide class of relative exact categories which, in general, do not satisfy the factorization axiom and confirm that it agrees with the…

Algebraic Geometry · Mathematics 2013-03-19 Satoshi Mochizuki

We provide a Cuntz-Pimsner model for graph of groups $C^*$-algebras. This allows us to compute the $K$-theory of a range of examples and show that graph of groups $C^*$-algebras can be realised as Exel-Pardo algebras. We also make a…

Operator Algebras · Mathematics 2021-07-27 Alexander Mundey , Adam Rennie

We provide a systematic approach to quantum mechanics from an information-theoretic perspective using the language of tensor networks. Our formulation needs only a single kind of object, so-called positive *-tensors. Physical models…

Quantum Physics · Physics 2020-03-19 Andreas Bauer

Let $\M=P\times{M}$ be a variable Mautner group. We describe the $C^*$-algebra $C^*(\M)$ of $\M$ in terms of an algebra of operator fields defined over $P\times{\C^2} $.

Operator Algebras · Mathematics 2021-03-19 Hedi Regeiba

In this paper, we introduce C*-algebraic partial compact quantum groups, which are quantizations of topological groupoids with discrete object set and compact morphism spaces. These C*-algebraic partial compact quantum groups are…

Operator Algebras · Mathematics 2019-01-29 Kenny De Commer

We apply the degree formula for connective $K$-theory to study rational contractions of algebraic varieties. Examples include rationally connected varieties and complete intersections.

Algebraic Geometry · Mathematics 2012-05-28 K. Zainoulline

We first prove that the K-theoretic Hall algebra of a preprojective algebra of affine type is isomorphic to the positive half of a quantum toroidal quantum group. An essential step consists to deform the K-theoretic Hall algebra so that the…

Representation Theory · Mathematics 2022-03-30 Michela Varagnolo , Eric Vasserot
‹ Prev 1 8 9 10 Next ›