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In the first part of the paper we describe the dual \ell^2(A)^{\prime} of the standard Hilbert C*-module \ell^2(A) over an arbitrary (not necessarily unital) C*-algebra A. When A is a von Neumann algebra, this enables us to construct…

Operator Algebras · Mathematics 2019-12-19 Damir Bakic

Using a variant of the Sobolev Embedding Theorem, we prove an uncertainty principle related to Gabor systems that generalizes the Balian-Low Theorem. Namely, if $f\in H^{p/2}(\R)$ and $\hat f\in H^{p'/2}(\R)$ with $1<p<\infty$,…

Classical Analysis and ODEs · Mathematics 2010-07-16 S. Zubin Gautam

Let $K$ be a compact group, and let $\rho$ be a representation of $K$ on a Hilbert space $\mathcal{H}_\rho$. We classify invariant subspaces of $\mathcal{H}_\rho$ in terms of range functions, and investigate frames of the form $\{\rho(\xi)…

Classical Analysis and ODEs · Mathematics 2015-09-24 Joseph W. Iverson

We investigate the completeness of Gabor systems with respect to several classes of window functions on rational lattices. Our main results show that the time-frequency shifts of every finite linear combination of Hermite functions with…

Mathematical Physics · Physics 2016-11-29 Karlheinz Gröchenig , Antti Haimi , José Luis Romero

Nonstationary Gabor frames were recently introduced in adaptive signal analysis. They represent a natural generalization of classical Gabor frames by allowing for adaptivity of windows and lattice in either time or frequency. In this paper…

Functional Analysis · Mathematics 2012-07-19 Monika Dörfler , Ewa Matusiak

G\v avruta studied atomic systems in terms of frames for range of operators (that is, for subspaces), namely $K$-frames, where the lower frame condition is controlled by the Hilbert-adjoint of a bounded linear operator $K$. For a locally…

Functional Analysis · Mathematics 2023-02-09 Jyoti , Lalit Kumar Vashisht , Uttam Kumar Sinha

We study sharp frame bounds of Gabor frames with the standard Gaussian window and prove that the square lattice optimizes both the lower and the upper frame bound among all rectangular lattices. This proves a conjecture of Floch, Alard &…

Functional Analysis · Mathematics 2016-10-05 Markus Faulhuber , Stefan Steinerberger

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 the construction of Gabor frames in $L^{2}(\mathbb{R})$ with generators in $\mathbf{S}_{0}(\mathbb{R})$ and with respect to time-frequency shifts from a rectangular lattice $\alpha\mathbb{Z}\times\beta\mathbb{Z}$ is equivalent…

Functional Analysis · Mathematics 2022-10-21 Ulrik B. R. Enstad , Mads S. Jakobsen , Franz Luef

We find sufficient conditions on a compactly supported function $g$, $\supp g = [a,b]$ which guarantee that the Gabor system $$\mathcal{G}(g;\alpha,\beta)=\{e^{2\pi i \beta m x}g(x-\alpha n)\}_{m,n\in\mathbb{Z}}$$ is a frame for all $\alpha…

Functional Analysis · Mathematics 2025-12-05 Yurii Belov , Aleksei Kulikov

The relationship between the frame bounds of frames (Gabor) for the space $L^2(\mathbb{R})$ with several generators from the Weyl-Heisenberg group and the scalars linked to the sum of frames is examined in this paper. We give sufficient…

Functional Analysis · Mathematics 2026-04-13 Divya Jindal , Jyoti , Lalit Kumar Vashisht

We prove explicit Erd\H{o}s--Wintner bounds for Cantor numeration systems via a simple trailing-window decomposition. We temporarily discard the last block of digits (the ``window'') and analyze the remaining prefix. The resulting bound has…

Number Theory · Mathematics 2026-01-12 Johann Verwee

In this work we deal with the recently introduced concept of weaving frames. We extend the concept to include multi-window frames and present the first sufficient criteria for a family of multi-window Gabor frames to be woven. We give a…

Functional Analysis · Mathematics 2018-06-12 Monika Dörfler , Markus Faulhuber

We give a construction of Gabor type frames for suitable separable subspaces of the non-separable Hilbert spaces $AP_2({\mathbb R})$ of almost periodic functions of one variable. Furthermore we determine a non-countable generalized frame…

Functional Analysis · Mathematics 2014-12-12 Paolo Boggiatto , Carmen Fernández , Antonio Galbis

Grafakos and Sansing \cite{GS} have shown how to obtain directionally sensitive time-frequency decompositions in $L^2(\mr^n)$ based on Gabor systems in $\ltr;$ the key tool is the "ridge idea," which lifts a function of one variable to a…

Functional Analysis · Mathematics 2014-02-18 Ole Christensen , Brigitte Forster , Peter Massopust

This work developes a quantitative framework for describing the overcompleteness of a large class of frames. A previous paper introduced notions of localization and approximation between two frames $\mathcal{F} = \{f_i\}_{i \in I}$ and…

Functional Analysis · Mathematics 2007-05-23 R. Balan , P. G. Casazza , C. Heil , Z. Landau

We show that Hilbert-Schmidt operators can be used to define frame-like structures for $L^2(\mathbb{R}^d)$ over lattices in $\mathbb{R}^{2d}$ that include multi-window Gabor frames as a special case. These frame-like structures are called…

Functional Analysis · Mathematics 2020-12-17 Eirik Skrettingland

Let $\mathbb{H}$ be a separable Hilbert space. In this paper we establish a generalization of Walnut's representation and Janssen's representation of the $\mathbb{H}-$valued Gabor frame operator on $\mathbb{H}-$valued weighted amalgam…

Functional Analysis · Mathematics 2020-03-11 Anirudha Poria , Jitendriya Swain

In this paper we develop constructive invertibility conditions for the twisted convolution. Our approach is based on splitting the twisted convolution with rational parameters into a finite number of weighted convolutions, which can be…

Functional Analysis · Mathematics 2007-05-23 Yonina C. Eldar , Ewa Matusiak , Tobias Werther

In this paper we use some ideas from \cite{FG-97, G-06} and consider the description of H\"{o}rmander type pseudo-differential operators on $\mathbb{R}^d$ ($d\geq1$), including the case of the magnetic pseudo-differential operators…

Analysis of PDEs · Mathematics 2026-05-19 Horia D. Cornean , Bernard Helffer , Radu Purice