Results 1 to 10 of about 3,267 (95)

A Generalization of a Classic Theorem in the Perturbation Theory for Linear Operators

open access: yesJournal of Mathematical Analysis and Applications, 1999
Let \(T\) be a bounded linear operator of a Banach space \(X\) into another \(Y\) such that the null space \(N(T)\) is a complementary subspace of \(X\) and the range \(R(T)\) a complementary subspace of \(Y\). This note considers the equation \(Tx= y\) for given \(y\) and its perturbed one \((T+\delta T)\widetilde x= y+\delta y\), to estimate the norm
Ding, Jiu, Huang, L.J.
openaire   +3 more sources

Perturbation theory for the approximation of stability spectra by QR methods for sequences of linear operators on a Hilbert space

open access: yesLinear Algebra and its Applications, 2012
The authors develop a quantitative perturbation theory for the approximation of stability spectra of sequences of infinite dimensional operators based on an infinite dimensional \(QR\) technique for determining Lyapunov exponents and Sacker-Sell spectrum. The results apply also in the case of stable but not necessarily distinct Lyapunov exponents.
Badawy, M., Van Vleck, E.
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Multiparameter perturbation theory of matrices and linear operators [PDF]

open access: yesTransactions of the American Mathematical Society, 2020
We show that a normal matrix A A with coefficients in
Parusiński, Adam, Rond, Guillaume
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Spectral theory for structured perturbations of linear operators [PDF]

open access: yesJournal of Spectral Theory, 2018
We characterize the spectrum (and its parts) of operators which can be represented as " G=A+BC“ for a "simpler" operator A and a structured perturbation
ENGEL, KLAUS JOCHEN OTTO, Adler, Martin
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The perturbation theory for linear operators of discrete type [PDF]

open access: yesPacific Journal of Mathematics, 1983
A perturbation result for unbounded operators of discrete type [\textit{N. Dunford} and \textit{J. Schwartz}, Linear Operators, part III (1971; Zbl 0243.47001): Spectral Operators, XIX, 2, Theorem 7] is derived using the notion of unconditional basis instead of assuming weak completeness of the underlying Banach space.
openaire   +2 more sources

Effective perturbation theory for linear operators

open access: yesJournal of Operator Theory, 2017
We propose a new approach to the spectral theory of perturbed linear operators , in the case of a simple isolated eigenvalue. We obtain two kind of results: ''radius bounds'' which ensure perturbation theory applies for perturbations up to an explicit size, and ''regularity bounds'' which control the variations of eigendata to any order.
openaire   +4 more sources

Perturbation Theory of Polynomials and Linear Operators

open access: yes
66 pages. The numbering of equations was changed, and a few more modifications were made. This final version will appear as a chapter in the book series "Handbook of Geometry and Topology of Singularities", Vol ...
Parusiński, Adam, Rainer, Armin
openaire   +2 more sources

Constructing Linear Operators Using Classical Perturbation Theory

open access: yesJournal of Guidance, Control, and Dynamics
This work introduces a methodology for generating linear operators that approximately represent nonlinear systems of perturbed ordinary differential equations. This is done through the application of classical perturbation theory via the Lindstedt–Poincaré expansion, followed by an extension of the space of configuration that guarantees the linear ...
Miguel Avillez, David Arnas
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IMPROVEMENTS ON THE PERTURBED HARMONIC OSCILLATOR LADDER OPERATORS METHOD IN THE NON LINEAR QUANTUM FIELD THEORY AND THE LASER THEORY

open access: yesActa Physica Sinica, 1989
The interaction potential with the form as V(x)= x2+λx2/(1+gx2) where g >0, appears in several areas of laser theory, quantum field theory, atom and nuclear physics. One could consider that the solution of the eigenequation either by the classical Rayleigh-Schr?dinger perturbation scheme or by the perturbed ladder operators scheme. Nevertheless, the
openaire   +1 more source

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