Results 51 to 60 of about 8,384 (123)

Some relationship between G-frames and frames [PDF]

Sahand Communications in Mathematical Analysis, 2015
In this paper we proved that every g-Riesz basis for Hilbert space $H$ with respect to $K$ by adding a condition is a Riesz basis for Hilbert $B(K)$-module $B(H,K)$. This is an extension of [A. Askarizadeh,M. A.
Mehdi Rashidi-Kouchi, Akbar Nazari
doaj  

Multi-tiling and Riesz bases

Advances in Mathematics, 2014
Let S be a bounded, Riemann measurable set in R^d, and L be a lattice. By a theorem of Fuglede, if S tiles R^d with translation set L, then S has an orthogonal basis of exponentials. We show that, under the more general condition that S multi-tiles R^d with translation set L, S has a Riesz basis of exponentials.
Grepstad, S., Lev, N.
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Riesz bases of exponentials on unbounded multi-tiles [PDF]

Proceedings of the American Mathematical Society, 2018
We prove the existence of Riesz bases of exponentials of L 2 ( Ω ) L^2(\Omega ) , provided that Ω ⊂ R d \Omega \subset \mathbb {R}^d is a measurable set of finite and positive measure, not ...
Cabrelli, Carlos, Carbajal, Diana Agustina   +1 more
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Pseudo-Duals of Frames and Modular Riesz Bases in Hilbert $C^\ast$-Modules [PDF]

Sahand Communications in Mathematical Analysis
In the present article, duals, approximate duals and pseudo-duals (generated by bounded and not necessarily adjointable operators) of a frame in a Hilbert $C^\ast$-module are characterized and some of their properties are obtained.
Morteza Mirzaee Azandaryani
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Finite extensions of Bessel sequences

, 2014
The paper studies finite extensions of Bessel sequences in infinite-dimensional Hilbert spaces. We provide a characterization of Bessel sequences that can be extended to frames by adding finitely many vectors.
Bakić, Damir, Berić, Tomislav
core   +1 more source

Riesz Bases and Multiresolution Analyses

Applied and Computational Harmonic Analysis, 1999
In this paper the author constructs a family of wavelet Riesz bases of compact support and arbitrary degree of smoothness, that cannot be obtained through a multiresolution analysis. The family is obtained by perturbing the orthonormal Haar wavelet with B-splines, giving thus a symmetric wavelet in closed form. The author also obtains several necessary
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Decompositions of g-Frames and Duals and Pseudoduals of g-Frames in Hilbert Spaces

Journal of Function Spaces, 2015
Firstly, we study the representation of g-frames in terms of linear combinations of simpler ones such as g-orthonormal bases, g-Riesz bases, and normalized tight g-frames.
Xunxiang Guo
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Riesz Bases in Krein Spaces

Indian Journal of Pure and Applied Mathematics
We start by introducing and studying the definition of a Riesz basis in a Krein space $(\mathcal{K},[.,.])$, along with a condition under which a Riesz basis becomes a Bessel sequence. The concept of biorthogonal sequence in Krein spaces is also introduced, providing an equivalent characterization of a Riesz basis.
Jahan, Shah, Johnson, P. Sam
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PERTURBATION OF WAVELET FRAMES AND RIESZ BASES I [PDF]

Communications of the Korean Mathematical Society, 2004
Summary: Suppose that \(\psi\in L^2(\mathbb{R})\) generates a wavelet frame (resp. Riesz basis) with bounds \(A\) and \(B\). If \(\phi\in L^2(\mathbb{R})\) satisfies \(|\widehat{\psi}(\xi)- \widehat{\phi}(\xi)| < \lambda \frac{|\xi|^\alpha } { ( 1 + | \xi | )^\gamma} \) for some positive constants \(\alpha , \gamma , \lambda\) such that \(1< 1+\alpha <
Lee, Jin, Ha, Young-Hwa
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The nonlocal problem for the $2n$ differential equations with unbounded operator coefficients and the involution

Karpatsʹkì Matematičnì Publìkacìï, 2018
We study a problem with periodic boundary conditions for a $2n$-order differential equation whose coefficients are non-self-adjoint operators. It is established that the operator of the problem has two invariant subspaces generated by the involution ...
Ya.O. Baranetskij, I.I. Demkiv, I.Ya. Ivasiuk, M.I. Kopach   +3 more
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