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We introduce non-commutative algebras, which can be associated with the function algebra of functions on a finite or half-finite cylinder. The algebras, which depend on a deformation parameter, are crossed product algebras of a partial…

Quantum Algebra · Mathematics 2023-09-12 Andreas Sykora

In the paper we describe the C*-algebras of noncommutative spherical tight frames over some C*-algebras and then apply to study the noncommutative version of the universal classifying space.

K-Theory and Homology · Mathematics 2007-05-23 Do Ngoc Diep

We construct spherical harmonics for fuzzy spheres of even and odd dimensions, generalizing the correspondence between finite matrix algebras and fuzzy two-spheres. The finite matrix algebras associated with the various fuzzy spheres have a…

High Energy Physics - Theory · Physics 2014-11-18 Sanjaye Ramgoolam

We define analogues of homogeneous coordinate algebras for noncommutative two-tori with real multiplication. We prove that the categories of standard holomorphic vector bundles on such noncommutative tori can be described in terms of graded…

Algebraic Geometry · Mathematics 2007-05-23 Alexander Polishchuk

A method for deforming C*-algebras is introduced, which applies to C*-algebras that can be described as the cross-sectional C*-algebra of a Fell bundle. Several well known examples of non-commutative algebras, usually obtained by deforming…

funct-an · Mathematics 2008-02-03 Beatriz Abadie , Ruy Exel

There are theories of coverings of $C^*$-algebras which can be included into a following list: coverings of commutative $C^*$-algebras, coverings of $C^*$-algebras of groupoids and foliations, coverings of noncommutative tori, the double…

Operator Algebras · Mathematics 2024-07-19 Petr Ivankov

We consider a generalization of the basic fuzzy torus to a fuzzy torus with non-trivial modular parameter, based on a finite matrix algebra. We discuss the modular properties of this fuzzy torus, and compute the matrix Laplacian for a…

High Energy Physics - Theory · Physics 2013-10-18 Paul Schreivogl , Harold Steinacker

A fuzzy circle and a fuzzy 3-sphere are constructed as subspaces of fuzzy complex projective spaces, of complex dimension one and three, by modifying the Laplacians on the latter so as to give unwanted states large eigenvalues. This leaves…

High Energy Physics - Theory · Physics 2009-11-10 Brian P. Dolan , Denjoe O'Connor

We describe how and to what extent the noncommutative two-torus can be approximated by a tower of finite-dimensional matrix geometries. The approximation is carried out for both irrational and rational deformation parameters by embedding…

High Energy Physics - Theory · Physics 2009-10-31 G. Landi , F. Lizzi , R. J. Szabo

The classification of structurable tori with nontrivial involution, which was begun by Allison and Yoshii, is completed. New examples of structurable tori are obtained using a construction of structurable algebras from a semilinear version…

Rings and Algebras · Mathematics 2008-09-06 Bruce Allison , John Faulkner , Yoji Yoshii

We construct and study noncommutative deformations of toric varieties by combining techniques from toric geometry, isospectral deformations, and noncommutative geometry in braided monoidal categories. Our approach utilizes the same fan…

Quantum Algebra · Mathematics 2015-12-16 Lucio Cirio , Giovanni Landi , Richard J. Szabo

The C*-algebra generated by the left-regular representation of $\mathbb{N}^n$ twisted by a $2$-cocycle is a Toeplitz extension of an $n$-dimensional noncommutative torus, on which each vector $r \in [0,\infty)^n$ determines a one-parameter…

Operator Algebras · Mathematics 2022-02-14 Zahra Afsar , Marcelo Laca , Jacqui Ramagge , Camila F. Sehnem

In this paper, we use the parametrised strict deformation quantization of C*-bundles obtained in a previous paper, and give more examples and applications of this theory. In particular, it is used here to classify H_3-twisted noncommutative…

Quantum Algebra · Mathematics 2011-08-19 K. C. Hannabuss , V. Mathai

We show that two C*-algebraic noncommutative tori are strongly Morita equivalent if and only if they have isomorphic ordered K_0-groups and centers, extending N. C. Phillips's result in the case that the algebras are simple. This is also…

Operator Algebras · Mathematics 2007-05-23 George A. Elliott , Hanfeng Li

We prove that curved noncommutative tori, introduced by Dabrowski and Sitarz, are Leibniz quantum compact metric spaces and that they form a continuous family over the group of invertible matrices with entries in the commutant of the…

Operator Algebras · Mathematics 2016-01-28 Frederic Latremoliere

We consider the problem of building non-invertible quantum symmetries (as characterized by actions of unitary fusion categories) on noncommutative tori. We introduce a general method to construct actions of fusion categories on inductive…

Quantum Algebra · Mathematics 2025-01-09 David E. Evans , Corey Jones

A noncommutative associative algebra of N=2 fuzzy supersphere is introduced. It turns out to possess a nontrivial automorphism which relates twisted chiral to twisted anti-chiral superfields and hence makes possible to construct…

High Energy Physics - Theory · Physics 2009-10-31 C. Klimcik

For all positive integers n we construct a 1-parameter family of conformal tori of revolution in the 3-sphere with n bulges. These tori arise by Darboux transformations of constant mean curvature tori but do not have constant mean curvature…

Differential Geometry · Mathematics 2009-09-23 K. Leschke

We compute the two-cocycles (or multipliers) of the free nilpotent groups of class $2$ and rank $n$ and give conditions for simplicity of the corresponding twisted group $C^*$-algebras. These groups are representation groups for…

Operator Algebras · Mathematics 2016-07-08 Tron Omland

We study superconformal interfaces between N=(1,1) supersymmetric sigma models on tori, which preserve a u(1)^{2d} current algebra. Their fusion is non-singular and, using parallel transport on CFT deformation space, it can be reduced to…

High Energy Physics - Theory · Physics 2015-06-05 Costas Bachas , Ilka Brunner , Daniel Roggenkamp