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We study nonuniform sampling in shift-invariant spaces and the construction of Gabor frames with respect to the class of totally positive functions whose Fourier transform factors as $ \hat g(\xi)= \prod_{j=1}^n (1+2\pi i\delta_j\xi)^{-1}…

Functional Analysis · Mathematics 2018-04-11 Karlheinz Gröchenig , José Luis Romero , Joachim Stöckler

We consider random sampling in finitely generated shift-invariant spaces $V(\Phi) \subset {\rm L}^2(\mathbb{R}^n)$ generated by a vector $\Phi = (\varphi_1,\ldots,\varphi_r) \in {\rm L}^2(\mathbb{R}^n)^r$. Following the approach introduced…

Functional Analysis · Mathematics 2014-10-20 Hartmut Führ , Jun Xian

We derive sufficient conditions for sampling with derivatives in shift-invariant spaces generated by a periodic exponential B-spline. The sufficient conditions are expressed with a new notion of measuring the gap between consecutive…

Functional Analysis · Mathematics 2023-11-15 Karlheinz Gröchenig , Irina Shafkulovska

We study the space spanned by the integer shifts of a bivariate Gaussian function and the problem of reconstructing any function in that space from samples scattered across the plane. We identify a large class of lattices, or more generally…

Functional Analysis · Mathematics 2024-08-07 José Luis Romero , Alexander Ulanovskii , Ilya Zlotnikov

We study the problem of sampling with derivatives in shift-invariant spaces generated by totally-positive functions of Gaussian type or by the hyperbolic secant. We provide sharp conditions in terms of weighted Beurling densities. As a…

Classical Analysis and ODEs · Mathematics 2022-05-04 Karlheinz Gröchenig , José Luis Romero , Joachim Stöckler

We discuss the problems of uniqueness, sampling and reconstruction with derivatives in the space of bandlimited functions. We prove that if X is sequence of real numbers such that the maximum gap between two consecutive samples is less than…

Functional Analysis · Mathematics 2020-07-23 A Antony Selvan

Let $f(z)=\sum_{n=1}^\infty a(n)q^n\in S^{\text{new}}_ k (\Gamma_0(N))$ be a newform with squarefree level $N$ that does not have complex multiplication. For a prime $p$, define $\theta_p\in[0,\pi]$ to be the angle for which $a(p)=2p^{( k…

Number Theory · Mathematics 2020-04-13 Jeremy Rouse , Jesse Thorner

In this article we study invariance properties of shift-invariant spaces in higher dimensions. We state and prove several necessary and sufficient conditions for a shift-invariant space to be invariant under a given closed subgroup of…

Classical Analysis and ODEs · Mathematics 2010-02-08 Magalí Anastasio , Carlos Cabrelli , Victoria Paternostro

For $p\ge 1$ let $\varphi_p(x)=x^2/2$ if $|x|\le 1$ and $\varphi_p(x)=1/p|x|^p-1/p+1/2$ if $|x|>1$. For a random variable $\xi$ let $\tau_{\varphi_p}(\xi)$ denote $\inf\{a\ge 0:\;\forall_{\lambda\in\mathbb{R}}\;…

Probability · Mathematics 2021-09-22 Krzysztof Zajkowski

We consider an independent and identically distributed (i.i.d.) random dynamical system of simple linear transformations on the unit interval $T_{\beta}(x)=\beta x$ (mod $1$), $x\in[0,1]$, $\beta>0$, which are the so-called…

Dynamical Systems · Mathematics 2024-04-26 Shintaro Suzuki

We show that a real-valued function $f$ in the shift-invariant space generated by a totally positive function of Gaussian type is uniquely determined, up to a sign, by its absolute values $\{|f(\lambda)|: \lambda \in \Lambda \}$ on any set…

Classical Analysis and ODEs · Mathematics 2020-12-16 José Luis Romero

Let $\pi:X\to Y$ be a factor map, where $(X,\sigma_X)$ and $(Y,\sigma_Y)$ are subshifts over finite alphabets. Assume that $X$ satisfies weak specification. Let $\ba=(a_1,a_2)\in \R^2$ with $a_1>0$ and $a_2\geq 0$. Let $f$ be a continuous…

Dynamical Systems · Mathematics 2009-09-24 De-Jun Feng

We construct a sequence ${\phi_i(\cdot-j)\mid j\in{\ZZ}, i=1,...,r}$ which constitutes a $p$-frame for the weighted shift-invariant space [V^p_{\mu}(\Phi)=\Big{\sum\limits_{i=1}^r\sum\limits_{j\in{\mathbb{Z}}}c_i(j)\phi_i(\cdot-j) \Big|…

Functional Analysis · Mathematics 2012-08-23 Stevan Pilipovic , Suzana Simic

In this paper, we discuss to the nonuniform sampling problem in principal shift-invariant subspaces of mixed Lebesgue spaces. We proposed a fast reconstruction algorithm which allows to exactly reconstruct the functions in the principal…

Functional Analysis · Mathematics 2018-01-26 Qingyue Zhang

We consider the problem of recovering a compactly-supported function from a finite collection of pointwise samples of its Fourier transform taking nonuniformly. First, we show that under suitable conditions on the sampling frequencies -…

Numerical Analysis · Mathematics 2014-04-08 Ben Adcock , Milana Gataric , Anders C. Hansen

We prove the equivalence of the frame property and the closedness for a weighted shift-invariant space. We also construct a sequence $\Phi^{2k+1}$ and the sequence of spaces $V^p_\mu(\Phi^{2k+1})$, $k\in{\mathbb{N}}$, on $\mathbb{R},$ with…

Functional Analysis · Mathematics 2011-06-01 Stevan Pilipovic , Suzana Simic

The convolution of a discrete measure, $x=\sum_{i=1}^ka_i\delta_{t_i}$, with a local window function, $\phi(s-t)$, is a common model for a measurement device whose resolution is substantially lower than that of the objects being observed.…

Optimization and Control · Mathematics 2019-11-27 Armin Eftekhari , Jared Tanner , Andrew Thompson , Bogdan Toader , Hemant Tyagi

Sampling in shift-invariant spaces is a realistic model for signals with smooth spectrum. In this paper, we consider phaseless sampling and reconstruction of real-valued signals in a shift-invariant space from their magnitude measurements…

Information Theory · Computer Science 2017-02-22 Cheng Cheng , Junzheng Jiang , Qiyu Sun

We provide sufficient density condition for a set of nonuniform samples to give rise to a set of sampling for multivariate bandlimited functions when the measurements consist of pointwise evaluations of a function and its first $k$…

Numerical Analysis · Mathematics 2016-09-12 Ben Adcock , Milana Gataric , Anders C. Hansen

This paper provides a necessary and sufficient condition on Tauberian constants associated to a centered translation invariant differentiation basis so that the basis is a density basis. More precisely, given $x \in \mathbb{R}^n$, let…

Classical Analysis and ODEs · Mathematics 2024-09-23 Paul A. Hagelstein , Ioannis Parissis
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