Finite eigenfuction approximations for continuous spectrum operators

In this paper, we introduce a new formulation of the theory of continuous spectrum eigenfunction expansions for self-adjoint operators and analyze the question of when operators may be approximated in an operator norm by finite sums of multiples of eigenprojections of multiplicity one. The theory is...

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Main Author: Robert M. Kauffman
Format: Article
Language:English
Published: Wiley 1993-01-01
Series:International Journal of Mathematics and Mathematical Sciences
Subjects:
Online Access:http://dx.doi.org/10.1155/S0161171293000018
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author Robert M. Kauffman
author_facet Robert M. Kauffman
author_sort Robert M. Kauffman
collection DOAJ
description In this paper, we introduce a new formulation of the theory of continuous spectrum eigenfunction expansions for self-adjoint operators and analyze the question of when operators may be approximated in an operator norm by finite sums of multiples of eigenprojections of multiplicity one. The theory is designed for application to ordinary and partial differential equations; relationships between the abstract theory and differential equations are worked out in the paper. One motivation for the study is the question of whether these expansions are susceptible to computation on a computer, as is known to be the case for many examples in the discrete spectrum case. The point of the paper is that continuous and discrete spectrum eigenfunction expansions are treated by the same formalism; both are limits in an operator norm of finite sums.
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spelling doaj-art-0392ea7397094d0fb5ad67ee92f268af2025-02-03T01:11:29ZengWileyInternational Journal of Mathematics and Mathematical Sciences0161-17121687-04251993-01-0116112210.1155/S0161171293000018Finite eigenfuction approximations for continuous spectrum operatorsRobert M. Kauffman0Department of Mathematics, University of Alabama at Birmingham, Birmingham, Alabama 35294, USAIn this paper, we introduce a new formulation of the theory of continuous spectrum eigenfunction expansions for self-adjoint operators and analyze the question of when operators may be approximated in an operator norm by finite sums of multiples of eigenprojections of multiplicity one. The theory is designed for application to ordinary and partial differential equations; relationships between the abstract theory and differential equations are worked out in the paper. One motivation for the study is the question of whether these expansions are susceptible to computation on a computer, as is known to be the case for many examples in the discrete spectrum case. The point of the paper is that continuous and discrete spectrum eigenfunction expansions are treated by the same formalism; both are limits in an operator norm of finite sums.http://dx.doi.org/10.1155/S0161171293000018continuous spectrum eigenfunction expansionself-adjoint operatorordinary differential operatorpartial differential operatorspectral theorem.
spellingShingle Robert M. Kauffman
Finite eigenfuction approximations for continuous spectrum operators
International Journal of Mathematics and Mathematical Sciences
continuous spectrum eigenfunction expansion
self-adjoint operator
ordinary differential operator
partial differential operator
spectral theorem.
title Finite eigenfuction approximations for continuous spectrum operators
title_full Finite eigenfuction approximations for continuous spectrum operators
title_fullStr Finite eigenfuction approximations for continuous spectrum operators
title_full_unstemmed Finite eigenfuction approximations for continuous spectrum operators
title_short Finite eigenfuction approximations for continuous spectrum operators
title_sort finite eigenfuction approximations for continuous spectrum operators
topic continuous spectrum eigenfunction expansion
self-adjoint operator
ordinary differential operator
partial differential operator
spectral theorem.
url http://dx.doi.org/10.1155/S0161171293000018
work_keys_str_mv AT robertmkauffman finiteeigenfuctionapproximationsforcontinuousspectrumoperators