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We construct a 2-parameter family of unitarily equivalent irreducible representations of the triply extended group $\g$ of translations of $\mathbb{R}^{4}$ associated with a family of its 4-dimensional coadjoint orbits and show how a…

Mathematical Physics · Physics 2017-06-13 S. Hasibul Hassan Chowdhury

Using the Weil-Brezin-Zak transform of solid state physics, we describe line bundles over elliptic curves in terms of Weyl operators. We then discuss the connection with finitely-generated projective modules over the algebra $A_\theta$ of…

Operator Algebras · Mathematics 2019-03-07 Francesco D'Andrea , Gaetano Fiore , Davide Franco

We investigate a set of functional equations defining a projection in the noncommutative 2-torus algebra $A_{\theta}$. The exact solutions of these provide various generalisations of the Powers-Rieffel projection. By identifying the…

K-Theory and Homology · Mathematics 2014-03-25 Michał Eckstein

We discuss gauge fields on tori in diverse dimensions, mainly in two and four dimensions. We construct various explicit gauge fields which have some topological charges and find the Dirac zero modes in the background of the gauge fields. By…

High Energy Physics - Theory · Physics 2010-04-05 Masashi Hamanaka , Hiroshige Kajiura

This paper is concerned with the characterization of $\alpha$-modulation spaces by Banach frames, i.e., stable and redundant non-orthogonal expansions, constituted of functions obtained by a suitable combination of translation, modulation…

Functional Analysis · Mathematics 2007-05-23 Massimo Fornasier

We investigate the structural properties of dual systems for nonstationary Gabor frames. In particular, we prove that some inverse nonstationary Gabor frame operators admit a Walnut-like representation, i.e. the operator acting on a…

Functional Analysis · Mathematics 2017-08-01 Nicki Holighaus

Using Gabor analysis, we give a complete characterization of all lattice sampling and interpolating sequences in the Fock space of polyanalytic functions, displaying a "Nyquist rate" which increases with $n$, the degree of polyanaliticity…

Functional Analysis · Mathematics 2009-12-02 Luis Daniel Abreu

We consider Gabor frames generated by a general lattice and a window function that belongs to one of the following spaces: the Sobolev space $V_1 = H^1(\mathbb R^d)$, the weighted $L^2$-space $V_2 = L_{1 + |x|}^2(\mathbb R^d)$, and the…

Functional Analysis · Mathematics 2021-06-07 Dae Gwan Lee , Friedrich Philipp , Felix Voigtlaender

In this article we describe extensions of some K-theory classes of Heisenberg modules over higher-dimensional noncommutative tori to projective modules over crossed products of noncommutative tori by finite cyclic groups, aka noncommutative…

Operator Algebras · Mathematics 2019-01-29 Sayan Chakraborty , Franz Luef

In this paper, we study a mirror duality on a generalized complex torus and a noncommutative complex torus. First, we derive a symplectic version of Riemann condition using mirror duality on ordinary complex tori. Based on this we will find…

High Energy Physics - Theory · Physics 2008-12-18 Eunsang Kim , Hoil Kim

The topic of this paper are (multi-window) Gabor frames for signals over finite Abelian groups, generated by an arbitrary lattice within the finite time-frequency plane. Our generic approach covers simultaneously multi-dimensional signals…

Group Theory · Mathematics 2008-03-17 H. G. Feichtinger , W. Kozek , F. Luef

We introduce a notion of Q-algebra that can be considered as a generalization of the notion of Q-manifold (a supermanifold equipped with an odd vector field obeying {Q,Q} =0). We develop the theory of connections on modules over Q-algebras…

High Energy Physics - Theory · Physics 2007-05-23 Albert Schwarz

In the last decade it has become clear that one of the central themes within Gabor analysis (with respect to general time-frequency lattices) is a duality theory for Gabor frames, including the Wexler-Raz biorthogonality condition, the…

Functional Analysis · Mathematics 2008-03-19 H. G. Feichtinger , F. Luef

Starting from the study of pseudodifferential operators with completely periodic symbols, we obtain results of continuity and invertibility of a class of Gabor operators on time-frequency invariant Banach spaces. As an applications we find…

Functional Analysis · Mathematics 2024-05-03 Gianluca Garello , Alessandro Morando

Let $X$ be an irreducible smooth projective algebraic curve of genus $g \geq 2$ over the ground field $\bc$ and let $G$ be a semisimple simply connected algebraic group. The aim of this paper is to introduce the notion of semistable and…

Algebraic Geometry · Mathematics 2012-11-06 V. Balaji , C. S. Seshadri

A Gabor system generated by a window function $g\in L^2(\mathbb{R}^d)$ and a separable set $\Lambda\times \Gamma \subset \mathbb{R}^{2d}$ is the collection of time-frequency shifts of $g$ given by $\mathcal G(g, \Lambda\times \Gamma) =…

Functional Analysis · Mathematics 2022-02-15 Christina Frederick , Azita Mayeli

This paper considers generators of Heisenberg modules in the case of twisted group $C^*$-algebras of closed subgroups of locally compact abelian groups and how the restrction and/or periodization of these generators yield generators for…

Operator Algebras · Mathematics 2018-11-28 Mads Sielemann Jakobsen , Franz Luef

We show that every rationally sampled dilation-and-modulation system is unitarily equivalent with a multi-window Gabor system. As a consequence, frame theoretical results from Gabor analysis can be directly transferred to…

Functional Analysis · Mathematics 2025-06-24 Jakob Lemvig

This is the second in a series of papers intended to set up a framework to study categories of modules in the context of non-commutative geometries. In \cite{mem} we introduced the basic DG category $\Pc_{\A^\bullet}$, the perfect category…

Quantum Algebra · Mathematics 2007-05-23 Jonathan Block

We study the noncommutative modular curve (which was already studied by Connes, Manin and Marcolli), and the space of geodesics on the usual modular curve, from the viewpoint of algebraic groups, linear algebra and class field theory. This…

Algebraic Geometry · Mathematics 2007-05-23 Frederic Paugam