Results 91 to 100 of about 714 (196)

On the Riesz Means of Expansion by Riesz Bases Formed by Eigen Functions for the Ordinary Differential Operator of 2mth Order

Ibn Al-Haitham Journal for Pure and Applied Sciences, 2017
  The aim of this paper is to prove a theorem on the Riesz means of expansions with respect to Riesz bases, which extends the previous results of [1] and [2] on the Schrödinger operator and the ordinary differential operator of 4-th order to the ...
A. A. Aswhad
doaj  

The Steklov spectrum of spherical cylinders

Mathematika, Volume 72, Issue 2, April 2026.
Abstract The Steklov problem on a compact Lipschitz domain is to find harmonic functions on the interior whose outward normal derivative on the boundary is some multiple (eigenvalue) of their trace on the boundary. These eigenvalues form the Steklov spectrum of the domain.
Spencer Bullent
wiley   +1 more source

Combining Riesz bases in $\mathbb R^d$

Revista Matemática Iberoamericana, 2016
We prove that every finite union of rectangles with edges parallel to the axes in \mathbb R^d admits a Riesz basis of exponentials.
Gady Kozma, Shahaf Nitzan
openaire   +1 more source

Bessel sequences, Riesz-like bases and operators in Triplets of Hilbert spaces [PDF]

, 2016
Riesz-like bases for a triplet of Hilbert spaces are investigated, in connection with an analogous study for more general rigged Hilbert spaces performed in a previous paper.
Giorgia Bellomonte, BELLOMONTE, Giorgia
core   +1 more source

Well-posedness and stability analysis of hybrid feedback systems using Shkalikov's theory [PDF]

Opuscula Mathematica, 2006
The modern method of analysis of the distributed parameter systems relies on the transformation of the dynamical model to an abstract differential equation on an appropriately chosen Banach or, if possible, Hilbert space.
Piotr Grabowski
doaj  

Riesz bases of reproducing kernels in small Fock spaces [PDF]

, 2019
International audienceWe give a complete characterization of Riesz bases of normalized reproducing kernels in the small Fock spaces $\mathcal{F}^2_{\varphi}$, the spaces of entire functions $f$ such that $f\mathrm{e}^{-\varphi} \in L^{2}(\mathbb{C ...
KELLAY, Karim, Omari, Youssef, Kellay, K.   +2 more
core   +1 more source

Convergence, interpolation, sampling and Riesz bases in the Fock spaces [PDF]

, 2013
Nous étudions le problème d'unicité, de l'interpolation faible et de la convergence de la série d'interpolation de Lagrange dans les espaces de Fock pondérés par des poids radiaux.
Dumont, Andre
core  

Riesz bases generated by the spectra of Sturm-Liouville problems

Electronic Journal of Differential Equations, 2013
Let ${lambda _n^2} _{n = 0}^infty$ be the spectra of a Sturm-Liouville problem on $[0,pi ]$. We investigate the question: Do the systems ${ cos(lambda_nx)} _{n = 0}^infty$ or ${ sin(lambda_n x)} _{n = 0}^infty$ form Riesz bases in ${L^2}[0,pi ]$? The
Tigran Harutyunyan, Avetik Pahlevanyan, Anna Srapionyan   +2 more
doaj  

Pseudo- Riesz Bases

In~\cite{holub1994bases} Holub introduced the concept of near-Riesz bases, as frames that can be considered Riesz bases for computational purposes or that exhibit certain desirable properties of Riesz bases. In this paper, we introduce a generalization of near-Riesz bases that includes sequences which are not necessarily frames.
Biswas, Deborpita, Mitkovski, Mishko
openaire   +2 more sources

Pre-frame operators, Besselian frames, and near-Riesz bases in Hilbert spaces [PDF]

, 1994
A problem of enduring interest in connection with the study of frames in Hubert space is that of characterizing those frames which can essentially be regarded as Riesz bases for computational purposes or which have certain desirable properties of Riesz ...
James R. Holub
core   +1 more source