The Fréchet Derivative of an Analytic Function of a Bounded Operator with Some Applications

The main result in this paper is the determination of the Fréchet derivative of an analytic function of a bounded operator, tangentially to the space of all bounded operators. Some applied problems from statistics and numerical analysis are included as a motivation for this study. The perturbation o...

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Main Authors: D. S. Gilliam, T. Hohage, X. Ji, F. Ruymgaart
Format: Article
Language:English
Published: Wiley 2009-01-01
Series:International Journal of Mathematics and Mathematical Sciences
Online Access:http://dx.doi.org/10.1155/2009/239025
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author D. S. Gilliam
T. Hohage
X. Ji
F. Ruymgaart
author_facet D. S. Gilliam
T. Hohage
X. Ji
F. Ruymgaart
author_sort D. S. Gilliam
collection DOAJ
description The main result in this paper is the determination of the Fréchet derivative of an analytic function of a bounded operator, tangentially to the space of all bounded operators. Some applied problems from statistics and numerical analysis are included as a motivation for this study. The perturbation operator (increment) is not of any special form and is not supposed to commute with the operator at which the derivative is evaluated. This generality is important for the applications. In the Hermitian case, moreover, some results on perturbation of an isolated eigenvalue, its eigenprojection, and its eigenvector if the eigenvalue is simple, are also included. Although these results are known in principle, they are not in general formulated in terms of arbitrary perturbations as required for the applications. Moreover, these results are presented as corollaries to the main theorem, so that this paper also provides a short, essentially self-contained review of these aspects of perturbation theory.
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series International Journal of Mathematics and Mathematical Sciences
spelling doaj-art-5cfa530d48f545c397fe52d23f386a792025-02-03T05:57:41ZengWileyInternational Journal of Mathematics and Mathematical Sciences0161-17121687-04252009-01-01200910.1155/2009/239025239025The Fréchet Derivative of an Analytic Function of a Bounded Operator with Some ApplicationsD. S. Gilliam0T. Hohage1X. Ji2F. Ruymgaart3Department of Mathematics and Statistics, Texas Tech University, Lubbock, TX 79409, USAInstitute for Numerical and Applied Mathematics, University of Göttingen, 37083 Göttingen, GermanyDepartment of Mathematics, Utah Valley University, Orem, UT 84058, USADepartment of Mathematics and Statistics, Texas Tech University, Lubbock, TX 79409, USAThe main result in this paper is the determination of the Fréchet derivative of an analytic function of a bounded operator, tangentially to the space of all bounded operators. Some applied problems from statistics and numerical analysis are included as a motivation for this study. The perturbation operator (increment) is not of any special form and is not supposed to commute with the operator at which the derivative is evaluated. This generality is important for the applications. In the Hermitian case, moreover, some results on perturbation of an isolated eigenvalue, its eigenprojection, and its eigenvector if the eigenvalue is simple, are also included. Although these results are known in principle, they are not in general formulated in terms of arbitrary perturbations as required for the applications. Moreover, these results are presented as corollaries to the main theorem, so that this paper also provides a short, essentially self-contained review of these aspects of perturbation theory.http://dx.doi.org/10.1155/2009/239025
spellingShingle D. S. Gilliam
T. Hohage
X. Ji
F. Ruymgaart
The Fréchet Derivative of an Analytic Function of a Bounded Operator with Some Applications
International Journal of Mathematics and Mathematical Sciences
title The Fréchet Derivative of an Analytic Function of a Bounded Operator with Some Applications
title_full The Fréchet Derivative of an Analytic Function of a Bounded Operator with Some Applications
title_fullStr The Fréchet Derivative of an Analytic Function of a Bounded Operator with Some Applications
title_full_unstemmed The Fréchet Derivative of an Analytic Function of a Bounded Operator with Some Applications
title_short The Fréchet Derivative of an Analytic Function of a Bounded Operator with Some Applications
title_sort frechet derivative of an analytic function of a bounded operator with some applications
url http://dx.doi.org/10.1155/2009/239025
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