Results 81 to 90 of about 20,701 (195)

Interpolation of Fredholm operators

Advances in Mathematics, 2016
We prove novel results on interpolation of Fredholm operators including an abstract factorization theorem. The main result of this paper provides sufficient conditions on the parameters $ \in (0,1)$ and $q\in \lbrack 1,\infty ]$ under which an operator $A$ is a Fredholm operator from the real interpolation space $(X_{0},X_{1})_{ ,q}$ to $(Y_{0},Y_{1})
Asekritova, I., Kruglyak, N., Mastyło, M.   +2 more
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The Spectral Property (ωπ): Equivalent Operators in Functionals, Families of Operators, and Tensor Products

Mathematics
The spectral property (ωπ) generalizes the a-Weyl theorem and characterizes the relationships between the spectrum and the upper semi-Fredholm spectrum.
Elvis Aponte, Ennis Rosas
doaj   +1 more source

Trace formulae for Schrödinger operators with complex-valued potentials on cubic lattices

Bulletin of Mathematical Sciences, 2018
We consider a class of Schrödinger operators with complex decaying potentials on the lattice. Using some classical results from complex analysis we obtain some trace formulae and use them to estimate zeros of the Fredholm determinant in terms of the ...
Evgeny Korotyaev, Ari Laptev
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Fredholm-type operators and index

Journal of Mathematical Analysis and Applications
While in \cite{HB} we studied classes of Fredholm-type operators defined by the homomorphism $\Pi$ from $L(X)$ onto the Calkin algebra $\mathcal{C}(X)$, $X$ being a Banach space, we study in this paper two classes of Fredholm-type operators defined by the homomorphism $\pi$ from $L(X)$ onto the algebra $\mathcal{C}_0(X)= L(X)/F_0(X),$ where $F_0(X)$ is
Alaa Hamdan, Mohammed Berkani
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Existence of solutions for non-necessarily cooperative systems involving Schrödinger operators

International Journal of Mathematics and Mathematical Sciences, 2001
We study the existence of a solution for a non-necessarily cooperative system of n equations involving Schrödinger operators defined on ℝN and we study also a limit case (the Fredholm Alternative (FA)). We derive results for semilinear systems.
Laure Cardoulis
doaj   +1 more source

Properness and Topological Degree for Nonlocal Reaction-Diffusion Operators

Abstract and Applied Analysis, 2011
The paper is devoted to integro-differential operators, which correspond to nonlocal reaction-diffusion equations considered on the whole axis. Their Fredholm property and properness will be proved. This will allow one to define the topological degree.
N. Apreutesei, V. Volpert
doaj   +1 more source

On the qualitative behaviors of Volterra-Fredholm integro differential equations with multiple time-varying delays

Arab Journal of Basic and Applied Sciences
This article considers a Volterra-Fredholm integro-differential equation including multiple time-varying delays. The aim of this article is to study the uniqueness of solution, the Ulam–Hyers–Rassias stability and the Ulam–Hyers stability of the Volterra-
Cemil Tunç, Osman Tunç
doaj   +1 more source

A multivalued version of Krasnoselskii’s theorem in generalized Banach spaces

Analele Stiintifice ale Universitatii Ovidius Constanta: Seria Matematica, 2014
The purpose of this paper is to extend Krasnoselskii’s fixed point theorem to the case of generalized Banach spaces for multivalued operators. As application, we will give an existence result for a system of Fredholm-Volterra type differential inclusions.
Petre Ioan-Radu
doaj   +1 more source

Krasnoselskii's theorem in generalized Banach spaces and application

Electronic Journal of Qualitative Theory of Differential Equations, 2012
The purpose of this paper is to extend Krasnoselskii's fixed point theorem to the case of generalized Banach spaces for singlevalued and multivalued operators.
I. R. Petre, Adrian Petrusel
doaj   +1 more source

Factorization of Fredholm operators in operator algebras

Matematychni Studii, 2004
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