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A mathematical construction of the conformal field theory (CFT) associated to a compact torus, also called the "nonlinear Sigma-model" or "lattice-CFT", is given. Underlying this approach to CFT is a unitary modular functor, the…

Mathematical Physics · Physics 2011-05-25 Hessel Posthuma

A classical theorem of Stone and von Neumann says that the Schr\"{o}dinger representation is, up to unitary equivalences, the only irreducible representation of the Heisenberg group on the Hilbert space of square-integrable functions on…

Mathematical Physics · Physics 2009-11-11 Maurice A. De Gosson

Heisenberg modules over noncommutative tori may also be viewed as Gabor frames. Building on this fact, we relate to deformations of noncommutative tori a bundle of Banach spaces induced by Heisenberg modules. The construction of this bundle…

Operator Algebras · Mathematics 2025-06-12 Malte Gerhold , Arvin Lamando , Franz Luef

We show that generalised time-frequency shifts on the Heisenberg group $\mathbf{H}_n \cong \mathbb{R}^{2n+1}$, realised as a unitary irreducible representation of a nilpotent Lie group acting on $L^{2}(\mathbf{H}_n)$, give rise to a novel…

Functional Analysis · Mathematics 2018-12-20 Véronique Fischer , David Rottensteiner , Michael Ruzhansky

We develop a usable perturbation theory for Weyl-Heisenberg frames. In particular, we prove that if $(E_{mb}T_{na}g)_{m,n\inmathbb Z}$ is a WH-frame and $h$ is a function which is close to $g$ in the Wiener Amalgam space norm, then…

Functional Analysis · Mathematics 2007-05-23 Peter G. Casazza , Ole Christensen , Mark C. Lammers

We show that, given a Banach space and a generator of an exponentially stable $C_{0}$-semigroup, a weakly admissible operator $g(A)$ can be defined for any $g$ bounded, analytic function on the left half-plane. This yields an (unbounded)…

Functional Analysis · Mathematics 2012-07-27 Felix Schwenninger , Hans Zwart

Using the notions of frame transform and of square integrable projective representation of a locally compact group $G$, we introduce a class of isometries (tight frame transforms) from the space of Hilbert-Schmidt operators in the carrier…

Quantum Physics · Physics 2008-11-26 P. Aniello , V. I. Man'ko , G. Marmo

For a topological group $G$, amenability can be characterized by the amenability of the convolution Banach algebra $L^1(G)$. Here a Banach algebra $A$ is called amenable if every bounded derivation from $A$ into any dual--type…

Functional Analysis · Mathematics 2025-07-01 Hikaru Awazu

We prove a generalised Yuan--Hunt--Ma\~n\'e Conjecture: if $\mathcal{F}$ is the Banach space of $\alpha$-H\"older functions, and $\mathcal{T}$ is either a space of Lipschitz expanding maps, or of Anosov diffeomorphisms, or the family of…

Dynamical Systems · Mathematics 2026-05-06 Zelai Hao , Yinying Huang , Oliver Jenkinson , Zhiqiang Li

We construct frames adapted to a given cover of the time-frequency or time-scale plane. The main feature is that we allow for quite general and possibly irregular covers. The frame members are obtained by maximizing their concentration in…

Functional Analysis · Mathematics 2015-04-27 Monika Dörfler , José Luis Romero

This paper provides a self-contained exposition of coorbit spaces associated to integrable group representations and quasi-Banach function spaces, and at the same time extends and simplifies previous work. The main results provide an…

Functional Analysis · Mathematics 2024-02-26 Jordy Timo van Velthoven , Felix Voigtlaender

We introduce a notion of a topologically flat locally convex module, which extends the notion of a flat Banach module and which is well adapted to the nonmetrizable setting (and especially to the setting of DF-modules). By using this…

Functional Analysis · Mathematics 2020-12-17 Alexei Yu. Pirkovskii , Krzysztof Piszczek

In this paper we give a general family of conformal invariants associated to bordered Riemann surfaces endowed with boundary parametrizations, or equivalently compact surfaces endowed with conformal maps. Each invariant is specified by a…

Differential Geometry · Mathematics 2026-05-13 Eric Schippers , Wolfgang Staubach

We describe a construction of wavelets (coherent states) in Banach spaces generated by ``admissible'' group representations. Our main targets are applications in pure mathematics while connections with quantum mechanics are mentioned. As an…

Functional Analysis · Mathematics 2007-05-23 Vladimir V. Kisil

We investigate and review how Fourier transform is involved in the analysis of a twisted group algebra $L^1(G, \sigma)$ for $G=\widehat{\Gamma}\times \Gamma$ and $\sigma:G\times G \to \mathbb{T}$ 2- cocycle where $\Gamma$ is a locally…

Operator Algebras · Mathematics 2019-08-14 Hyun Ho Lee

On a locally compact group we introduce covariant quantization schemes and analogs of phase space representations as well as mixed-state localization operators. These generalize corresponding notions for the affine group and the Heisenberg…

Functional Analysis · Mathematics 2023-07-20 Simon Halvdansson

We consider the coorbit theory associated to general continuous wavelet transforms arising from a square-integrable, irreducible quasi-regular representation of a semidirect product group $G = \mathbb{R}^d \rtimes H$. The existence of…

Functional Analysis · Mathematics 2015-05-21 Hartmut Führ , Reihaneh Raisi Tousi

We provide explicit criteria for wavelets to give rise to frames and atomic decompositions in ${\rm L}^2(\mathbb{R}^d)$, but also in more general Banach function spaces. We consider wavelet systems that arise by translating and dilating the…

Functional Analysis · Mathematics 2013-08-22 Hartmut Führ

We call a function "constructible" if it has a globally subanalytic domain and can be expressed as a sum of products of globally subanalytic functions and logarithms of positively-valued globally subanalytic functions. Our main theorem…

Classical Analysis and ODEs · Mathematics 2013-04-24 Raf Cluckers , Daniel J. Miller

We introduce a uniform structure on any Hilbert $C^*$-module $\mathcal N$ and prove the following theorem: suppose, $F:{\mathcal M}\to {\mathcal N}$ is a bounded adjointable morphism of Hilbert $C^*$-modules over $\mathcal A$ and $\mathcal…

Operator Algebras · Mathematics 2018-12-11 Evgenij Troitsky