Error-estimates for the method of least squares of finding eigenvalues and eigenfunctions
Error-estimates for the Ritz's method of finding eigenvalues and eigenfunctions
Expansions in Generalized Eigenfunctions of Selfadjoint Operators.
Finite eigenfunction approximations for continuous spectrum operators.
Generalized eigenfunction expansions and spectral decompositions
The paper relates several generalized eigenfunction expansions to classical spectral decomposition properties. From this perspective one explains some recent results concerning the classes of decomposable and generalized scalar operators. In particular a universal dilation theory and two different functional models for related classes of operators are presented.
Generalized Eigenvector Expansion for Weakly Perturbated Discrete Operators
Global Properties of the Minimal Branch of a Class of Nonlinear Variational Problems.
Hardy-Lorentz spaces and expansions in eigenfunctions of the Laplace-Beltrami operator on compact manifolds
Incomplete Data problems in X-Ray Computerized Tomography. II. Truncated Projections and Region-of-Interest Tomography.
Incomplete Data Problems in X-Ray Computerized Tomography. I. Singular Value Decomposition of the Limited Angle Transform.
Le comportement asymptotique des valeurs propres d'un opérateur
Linksdefinite singuläre kanonische Eigenwertprobleme. I.
Linksdefinite singuläre kanonische Eigenwertprobleme. II.
Méthode fonctionnelle en théorie des champs
Nilpotent Lie groups and eigenfunction expansions of Schrödinger operators II
Nilpotent Lie groups and summability of eigenfunction expansions of Schrödinger operators
On determination of eigenvalues and eigenvectors of selfadjoint operators
Two simple methods for approximate determination of eigenvalues and eigenvectors of linear self-adjoint operators are considered in the following two cases: (i) lower-upper bound of the spectrum of is an isolated point of ; (ii) (not necessarily an isolated point of with finite multiplicity) is an eigenvalue of .
On eigenfunction expansions and scattering theory.
On generalized eigenfunctions of operators in a Hilbert space
On operators Cauchy dual to 2-hyperexpansive operators: the unbounded case
The Cauchy dual operator T’, given by , provides a bounded unitary invariant for a closed left-invertible T. Hence, in some special cases, problems in the theory of unbounded Hilbert space operators can be related to similar problems in the theory of bounded Hilbert space operators. In particular, for a closed expansive T with finite-dimensional cokernel, it is shown that T admits the Cowen-Douglas decomposition if and only if T’ admits the Wold-type decomposition (see Definitions 1.1 and 1.2 below)....