Results 31 to 40 of about 142 (138)
The spectrum of a class of almost periodic operators
International Journal of Mathematics and Mathematical Sciences, Volume 2003, Issue 36, Page 2277-2301, 2003., 2003 For almost Mathieu operators, it is shown that the occurrence of Cantor spectrum and the existence, for every point in the spectrum and suitable phase parameters, of at least one localized eigenfunction which decays exponentially are inconsistent properties.
Norbert Riedel
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Open Mathematics, 2020 In this paper, we describe a method to solve the problem of finding periodic solutions for second-order neutral delay-differential equations with piecewise constant arguments of the form x″(t) + px″(t − 1) = qx([t]) + f(t), where [⋅] denotes the greatest
I. Muminov Mukhiddin, H. M. Murid Ali
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Weighted Spectral Properties of a Hadamard‐Type Fractional Operator
Journal of Function Spaces, Volume 2026, Issue 1, 2026.In this paper, we investigate a class of Hadamard‐type fractional operators from the viewpoint of functional analysis and spectral theory. The analysis is carried out on the bounded interval (1, R) within the weighted Hilbert space L2((1, R), dx/x), which naturally arises from the logarithmic structure associated with the Hadamard fractional derivative.
Muath Awadalla +2 more
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On the largest analytic set for cyclic operators
International Journal of Mathematics and Mathematical Sciences, Volume 2003, Issue 30, Page 1899-1909, 2003., 2003 We describe the set of analytic bounded point evaluations for an arbitrary cyclic bounded linear operator T on a Hilbert space ℋ; some related consequences are discussed. Furthermore, we show that two densely similar cyclic Banach‐space operators possessing Bishop′s property (β) have equal approximate point spectra.
A. Bourhim
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Generalized Derivations and Norm Equality in Normed Ideals [PDF]
, 2011 2000 Mathematics Subject Classification: 47A10, 47A12, 47A30, 47B10, 47B20, 47B37, 47B47, 47D50.We compare the norm of a generalized derivation on a Hilbert space with the norm of its restrictions to Schatten norm ...
Barraa, Mohamed
core
Spectral Analysis of the Dunkl–Bessel Laplacian and Its Applications
Journal of Function Spaces, Volume 2026, Issue 1, 2026.In this paper, we develop a concrete von Neumann spectral analysis of the Dunkl–Bessel Laplacian −Δκ,αW, considered through its maximal even distributional realization on Lκ,α2,ℝ+d+1. We first prove that this realization is nonnegative and self‐adjoint and that its spectrum coincides with its continuous spectrum and is equal to [0, +∞), whereas its ...
Abdelilah El Mourni +3 more
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Common fixed point theorems for a pair of countably condensing mappings in ordered banach spaces
International Journal of Stochastic Analysis, Volume 16, Issue 3, Page 243-248, 2003., 2003 In this paper some common fixed point theorems for a pair of multivalued weakly isotone mappings on an ordered Banach space are proved.
B. C. Dhage +2 more
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Nonlocal heat equations with generalized fractional Laplacian
Advances in Nonlinear AnalysisWe study heat equations with generalized fractional Laplacian, which is defined by the spectral theory. Here we develop the existence theory for those equations. Also, we present some numerical simulations for our problems.
Kossowski Igor, Przeradzki Bogdan
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On unbounded commuting Jacobi operators and some related issues
Concrete Operators, 2019 We consider the situations, when two unbounded operators generated by infinite Jacobi matrices, are self-adjoint and commute. It is found that if two Jacobi matrices formally commute, then two corresponding operators are either self-adjoint and commute ...
Osipov Andrey
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The Property (EA) and Local Spectral Theory
International Journal of Mathematics and Mathematical Sciences, Volume 2025, Issue 1, 2025.In this paper, we introduce and study the spectral property (EA). This property means that the difference between the approximate point spectrum and the upper semi‐Fredholm spectrum coincides with the difference between the approximate point spectrum and the upper semi‐Weyl spectrum.
Elvis Aponte +3 more
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