Results 21 to 30 of about 485,398 (210)

On Analytic Perturbations of Linear Equations in the Case of Incomplete Generalized Jordan Set

open access: yesСовременная математика: Фундаментальные направления, 2022
Based on the methods of the theory of bifurcations, the problem of perturbation of linear equations by small analytic terms is considered. In contrast to the work of Trenogin [7], the case of an incomplete generalized Jordan set of a linear Fredholm ...
D. G. Rakhimov, D. Akhmadzhanova
doaj   +1 more source

On tau functions associated with linear systems [PDF]

open access: yes, 2012
\noindent {\bf Abstract} This paper considers the Fredholm determinant $\det (I-\Gamma_x)$ of a Hankel integral operator on $L^2(0, \infty )$ with kernel $\phi (s+t+2x)$, where $\phi$ is a matrix scattering function.
Newsham, Samantha, Blower, Gordon
core   +4 more sources

Regularised discretisations obtained from first‐kind Fredholm operator equations

open access: yesIET Microwaves, Antennas & Propagation, 2021
Judicious discretisations of certain first‐kind Fredholm operator equations are tantamount to Fredholm infinite‐matrix equations of the second kind. We give detailed explanations for the occurrence of this interesting and useful phenomenon and carefully ...
George Fikioris
doaj   +1 more source

Regularized Asymptotic Solutions of a Singularly Perturbed Fredholm Equation with a Rapidly Varying Kernel and a Rapidly Oscillating Inhomogeneity

open access: yesAxioms, 2022
This article investigates an equation with a rapidly oscillating inhomogeneity and with a rapidly decreasing kernel of an integral operator of Fredholm type.
Dana Bibulova   +2 more
doaj   +1 more source

On the quasi-Fredholm and Saphar spectrum of strongly continuous Cosine operator function

open access: yesMoroccan Journal of Pure and Applied Analysis, 2021
Let (C(t))t∈𝕉 be a strongly continuous cosine family and A be its infinitesimal generator. In this work, we prove that, if C(t) – coshλt is Saphar (resp. quasi-Fredholm) operator and λt /∉iπ𝕑, then A – λ2 is also Saphar (resp.
Boua Hamid
doaj   +1 more source

Fredholm Operators: A Counterexample [PDF]

open access: yesProceedings of the American Mathematical Society, 1969
In 1960 Pietsch [I] gave an example of a locally convex linear topological space for which the set of Fredholm operators is not open. It is the purpose of this note to show that the Fredholm class is not open for any weak locally convex space. A Hausdorff locally convex space is called a weak locally convex space if every null-neighborhood contains a ...
openaire   +1 more source

Unbounded B-Fredholm operators on Hilbert spaces [PDF]

open access: yes, 2008
This paper is concerned with the study of a class of closed linear operators densely defined on a Hilbert space H and called B-Fredholm operators.
Berkani, M.   +3 more
core   +1 more source

A Symbolic Method for Solving a Class of Convolution-Type Volterra–Fredholm–Hammerstein Integro-Differential Equations under Nonlocal Boundary Conditions

open access: yesAlgorithms, 2023
Integro-differential equations involving Volterra and Fredholm operators (VFIDEs) are used to model many phenomena in science and engineering. Nonlocal boundary conditions are more effective, and in some cases necessary, because they are more accurate ...
Efthimios Providas   +1 more
doaj   +1 more source

Parity and generalized multiplicity [PDF]

open access: yes, 1991
Assuming that X and Y are Banach spaces and that T is a path of linear Fredholm operators with invertible endpoints, in [F-Pl] we defined a homotopy invariant "the parity of T .
Fitzpatrickp.   +4 more
core   +1 more source

Elliptic operators and their symbols

open access: yesDemonstratio Mathematica, 2019
We consider special elliptic operators in functional spaces on manifolds with a boundary which has some singular points. Such an operator can be represented by a sum of operators, and for a Fredholm property of an initial operator one needs a Fredholm ...
Vasilyev Vladimir
doaj   +1 more source

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