Results 1 to 10 of about 3,557 (127)

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

Journal 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.
exaly   +2 more sources

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

Linear 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.
Erik van Vleck
exaly   +2 more sources

Singularly perturbed rank one linear operators

Математичні Студії, 2021
The basic principles of the theory of singularly perturbed self-adjoint operators are generalized to the case of closed linear operators with non-symmetric perturbation of rank one.
M.E. Dudkin, O. Yu. Dyuzhenkova
doaj   +1 more source

Global Perturbation of Nonlinear Eigenvalues

Advanced Nonlinear Studies, 2021
This paper generalizes the classical theory of perturbation of eigenvalues up to cover the most general setting where the operator surface 𝔏:[a,b]×[c,d]→Φ0⁢(U,V){\mathfrak{L}:[a,b]\times[c,d]\to\Phi_{0}(U,V)}, (λ,μ)↦𝔏⁢(λ,μ){(\lambda,\mu)\mapsto\mathfrak ...
López-Gómez Julián, Sampedro Juan Carlos   +1 more
doaj   +1 more source

On the periodic solutions for some retarded partial differential equations by the use of semi-Fredholm operators

Cubo, 2021
The main goal of this work is to examine the periodic dynamic behavior of some retarded periodic partial differential equations (PDE). Taking into consideration that the linear part realizes the Hille-Yosida condition, we discuss the Massera’s problem to
Abdelhai Elazzouzi, Khalil Ezzinbi, Mohammed Kriche   +2 more
doaj   +1 more source

On the nonlinear perturbations of self-adjoint operators

Advances in Nonlinear Analysis, 2022
Using elements of the theory of linear operators in Hilbert spaces and monotonicity tools we obtain the existence and uniqueness results for a wide class of nonlinear problems driven by the equation Tx=N(x)Tx=N\left(x), where TT is a self-adjoint ...
Bełdziński Michał, Galewski Marek, Majdak Witold   +2 more
doaj   +1 more source

Multiparameter perturbation theory of matrices and linear operators [PDF]

Transactions of the American Mathematical Society, 2020
We show that a normal matrix A A with coefficients in
Parusiński, Adam, Rond, Guillaume
openaire   +3 more sources

Spectral theory for structured perturbations of linear operators [PDF]

Journal 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
openaire   +3 more sources

The ChPT: top-down and bottom-up

Journal of High Energy Physics, 2021
In this work, higher-derivative corrections of the non-linear sigma model of both even and odd intrinsic-parity sectors are systematically studied, focusing on ordered amplitudes of flavor scalars in massless limit. It should correspond to a theory known
Karol Kampf
doaj   +1 more source

Nonlinear differential equations with perturbed Dirichlet integral boundary conditions

Boundary Value Problems, 2021
This paper is devoted to prove the existence of positive solutions of a second order differential equation with a nonhomogeneous Dirichlet conditions given by a parameter dependence integral.
Alberto Cabada, Javier Iglesias
doaj   +1 more source