Results 41 to 50 of about 147 (142)
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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Spectral integration and spectral theory for non‐Archimedean Banach spaces
International Journal of Mathematics and Mathematical Sciences, Volume 31, Issue 7, Page 421-442, 2002., 2002 Banach algebras over arbitrary complete non‐Archimedean fields are considered such that operators may be nonanalytic. There are different types of Banach spaces over non‐Archimedean fields. We have determined the spectrum of some closed commutative subalgebras of the Banach algebra ℒ(E) of the continuous linear operators on a free Banach space E ...
S. Ludkovsky, B. Diarra
wiley +1 more source
Negative Powers of Contractions Having a Strong AA+ Spectrum
Moroccan Journal of Pure and Applied Analysis, 2023 Zarrabi proved in 1993 that if the spectrum of a contraction T on a Banach space is a countable subset of the unit circle 𝕋, and if limn→+∞log(‖T−n‖)n=0{\lim _{n \to + \infty }}{{\log \left( {\left\| {{T^{ - n}}} \right\|} \right)} \over {\sqrt n ...
Esterle Jean
doaj +1 more source
International Journal of Mathematics and Mathematical Sciences, Volume 2025, Issue 1, 2025.For the Weinstein Laplacian considered on the Hilbert space which makes it a self‐adjoint operator, the Von Neumann spectral decomposition is given. As applications, a new integral representation for the Weinstein heat kernel is given. Also, it is proved that the spectrum of the semigroup associated with the Weinstein Laplacian is reduced to its ...
Abdelilah El Mourni +3 more
wiley +1 more source
Continuity and general perturbation of the Drazin inverse for closed linear operators
Abstract and Applied Analysis, Volume 7, Issue 6, Page 335-347, 2002., 2002 We study perturbations and continuity of the Drazin inverse of a closed linear operator A and obtain explicit error estimates in terms of the gap between closed operators and the gap between ranges and nullspaces of operators. The results are used to derive a theorem on the continuity of the Drazin inverse for closed operators and to describe the ...
N. Castro González +2 more
wiley +1 more source
Journal of Mathematics, Volume 2025, Issue 1, 2025.This paper investigates an abstract nonhomogeneous backward Cauchy problem governed by an unbounded linear operator in a Hilbert space H. The coefficient operator in the equation is assumed to be unbounded, self‐adjoint, positive, and to possess a discrete spectrum, with data prescribed at the final time t = T.
Nihed Teniou, Xian-Ming Gu
wiley +1 more source
Almost Jordan homomorphisms on Fréchet algebras
, 2021 In this paper we study the notation of almost Jordan homomorphism between Fréchet algebras. We show that if (A; (pn)) is a Fréchet algebra and T : A → ℂ is a almost Jordan homomorphism, then either T is homomorphism, or it is continuous.
Zivari-Kazempour, A. +2 more
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Certain properties of the essential spectra in Banach spaces [PDF]
, 2017 Paper presented at the 4th Strathmore International Mathematics Conference (SIMC 2017), 19 - 23 June 2017, Strathmore University, Nairobi, Kenya.Let X be an arbitrary Banach space, and L (X) be the set of all bounded linear operators on X.
Agure, J. O. +2 more
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An introduction to the distorted Fourier transform
Advanced Nonlinear StudiesThis article is intended as an introduction to the distorted Fourier transform associated with a Schrödinger operator on the line or the half-line. This versatile tool has seen numerous applications in nonlinear PDE in recent years.
Ko Haram, Schlag Wilhelm
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On the generalized Kato spectrum [PDF]
, 2011 2010 Mathematics Subject Classification: 47A10.We show that the symmetric difference between the generalized Kato spectrum and the essential spectrum defined in [7] by sec(T) = {l О C ; R(lI-T) is not closed } is at most countable and we also give some
Messirdi, Bekkai, Benharrat, Mohammed
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