Results 61 to 70 of about 560 (182)

On the Generalized Bm-Riesz Difference Sequence Space and β-Property

Journal of Inequalities and Applications, 2009
We introduce the generalized Riesz difference sequence space rq(p,Bm) which is defined by rq(p,Bm)={x=(xk)∈w:Bmx∈rq(p)} where rq(p) is the Riesz sequence space defined by Altay and Başar.
Metin Başarir, Mustafa Kayikçi   +1 more
doaj   +1 more source

RVSIM: a feature similarity method for full-reference image quality assessment

EURASIP Journal on Image and Video Processing, 2018
Image quality assessment is an important topic in the field of digital image processing. In this study, a full-reference image quality assessment method called Riesz transform and Visual contrast sensitivity-based feature SIMilarity index (RVSIM) is ...
Guangyi Yang, Deshi Li, Fan Lu, Yue Liao, Wen Yang   +4 more
doaj   +1 more source

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

Inner‐Layer Asymptotics in Partially Perforated Domains: Coupling Across Flat and Oscillating Interfaces

Mathematical Methods in the Applied Sciences, Volume 49, Issue 4, Page 3353-3384, 15 March 2026.
ABSTRACT The article examines a boundary‐value problem in a bounded domain Ωε$$ {\Omega}_{\varepsilon } $$ consisting of perforated and imperforate regions, with Neumann conditions prescribed at the boundaries of the perforations. Assuming the porous medium has symmetric, periodic structure with a small period ε$$ \varepsilon $$, we analyze the limit ...
Taras Melnyk
wiley   +1 more source

Semiclassical inequalities for Dirichlet and Neumann Laplacians on convex domains

Communications on Pure and Applied Mathematics, Volume 79, Issue 3, Page 762-822, March 2026.
Abstract We are interested in inequalities that bound the Riesz means of the eigenvalues of the Dirichlet and Neumann Laplacians in terms of their semiclassical counterpart. We show that the classical inequalities of Berezin–Li–Yau and Kröger, valid for Riesz exponents γ≥1$\gamma \ge 1$, extend to certain values γ<1$\gamma <1$, provided the underlying ...
Rupert L. Frank, Simon Larson
wiley   +1 more source

Characterizing the R-duality of g-frames

Journal of Inequalities and Applications, 2019
In this paper, we define the g-Riesz-dual of a given special operator-valued sequence with respect to g-orthonormal bases for a separable Hilbert space.
Liang Li, Pengtong Li
doaj   +1 more source

Potential trace inequalities via a Calderón‐type theorem

Journal of the London Mathematical Society, Volume 113, Issue 3, March 2026.
Abstract In this paper, we develop a general theoretical tool for the establishment of the boundedness of notoriously difficult operators (such as potentials) on certain specific types of rearrangement‐invariant function spaces from analogous properties of operators that are easier to handle (such as fractional maximal operators).
Zdeněk Mihula, Luboš Pick, Daniel Spector   +2 more
wiley   +1 more source

Sufficient conditions for functions to form Riesz bases in L_2 and applications to nonlinear boundary-value problems

Electronic Journal of Differential Equations, 2001
We find sufficient conditions for systems of functions to be Riesz bases in $L_2(0,1)$. Then we improve a theorem presented in [13] by showing that a ``standard'' system of solutions of a nonlinear boundary-value problem, normalized to 1, is a Riesz ...
Peter E. Zhidkov
doaj  

On Almost Orthogonal Frames

International Journal of Mathematics and Mathematical Sciences, 2012
Almost orthogonal frames have been introduced and studied. It has been proved that a bounded almost orthogonal frame satisfies Feichtinger conjecture. Also, we prove that a bounded almost orthogonal frame contains a Riesz basis.
Virender, A. Zothansanga, S. K. Kaushik
doaj   +1 more source

The nonlocal boundary value problem with perturbations of mixed boundary conditions for an elliptic equation with constant coefficients. I

Karpatsʹkì Matematičnì Publìkacìï, 2019
In this article we investigate a problem with nonlocal boundary conditions which are multipoint perturbations of mixed boundary conditions in the unit square $G$ using the Fourier method. The properties of a generalized transformation operator $R: L_2(G)
Ya.O. Baranetskij, P.I. Kalenyuk, M.I. Kopach, A.V. Solomko   +3 more
doaj   +1 more source