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On a theorem of Livsic

Aleman, Alexandru LU ; Martin, R. T. W. and Ross, William T. (2013) In Journal of Functional Analysis 264(4). p.999-1048
Abstract
The theory of symmetric operators has several deep applications to the function theory of certain reproducing kernel Hilbert spaces of analytic functions, as well as to the study of ordinary differential operators in mathematical physics. Examples of simple symmetric operators include multiplication operators on various spaces of analytic functions (model subspaces of Hardy spaces, de Branges-Rovnyak spaces, Herglotz spaces), Sturm-Liouville and Schrodinger differential operators, Toeplitz operators, and infinite Jacobi matrices. In this paper we develop a general representation theory of simple symmetric operators with equal deficiency indices, and obtain a collection of results which refine and extend classical works of Krein and Livsic.... (More)
The theory of symmetric operators has several deep applications to the function theory of certain reproducing kernel Hilbert spaces of analytic functions, as well as to the study of ordinary differential operators in mathematical physics. Examples of simple symmetric operators include multiplication operators on various spaces of analytic functions (model subspaces of Hardy spaces, de Branges-Rovnyak spaces, Herglotz spaces), Sturm-Liouville and Schrodinger differential operators, Toeplitz operators, and infinite Jacobi matrices. In this paper we develop a general representation theory of simple symmetric operators with equal deficiency indices, and obtain a collection of results which refine and extend classical works of Krein and Livsic. In particular, we provide an alternative proof of a theorem of Livsic which characterizes when two simple symmetric operators with equal deficiency indices are unitarily equivalent. Moreover, we provide a new, more easily computable formula for the Livsic characteristic function of a simple symmetric operator. (C) 2012 Elsevier Inc. All rights reserved. (Less)
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author
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type
Contribution to journal
publication status
published
subject
keywords
Simple symmetric operators, Reproducing kernel Hilbert space, Livsic, characteristic function, de Branges-Rovnyak spaces
in
Journal of Functional Analysis
volume
264
issue
4
pages
999 - 1048
publisher
Elsevier
external identifiers
  • wos:000314133700005
  • scopus:84872011094
ISSN
0022-1236
DOI
10.1016/j.jfa.2012.11.015
language
English
LU publication?
yes
id
0fe410dd-1a05-43a9-9bad-5b1ab2f81405 (old id 3590929)
date added to LUP
2016-04-01 13:33:28
date last changed
2022-03-21 19:13:56
@article{0fe410dd-1a05-43a9-9bad-5b1ab2f81405,
  abstract     = {{The theory of symmetric operators has several deep applications to the function theory of certain reproducing kernel Hilbert spaces of analytic functions, as well as to the study of ordinary differential operators in mathematical physics. Examples of simple symmetric operators include multiplication operators on various spaces of analytic functions (model subspaces of Hardy spaces, de Branges-Rovnyak spaces, Herglotz spaces), Sturm-Liouville and Schrodinger differential operators, Toeplitz operators, and infinite Jacobi matrices. In this paper we develop a general representation theory of simple symmetric operators with equal deficiency indices, and obtain a collection of results which refine and extend classical works of Krein and Livsic. In particular, we provide an alternative proof of a theorem of Livsic which characterizes when two simple symmetric operators with equal deficiency indices are unitarily equivalent. Moreover, we provide a new, more easily computable formula for the Livsic characteristic function of a simple symmetric operator. (C) 2012 Elsevier Inc. All rights reserved.}},
  author       = {{Aleman, Alexandru and Martin, R. T. W. and Ross, William T.}},
  issn         = {{0022-1236}},
  keywords     = {{Simple symmetric operators; Reproducing kernel Hilbert space; Livsic; characteristic function; de Branges-Rovnyak spaces}},
  language     = {{eng}},
  number       = {{4}},
  pages        = {{999--1048}},
  publisher    = {{Elsevier}},
  series       = {{Journal of Functional Analysis}},
  title        = {{On a theorem of Livsic}},
  url          = {{http://dx.doi.org/10.1016/j.jfa.2012.11.015}},
  doi          = {{10.1016/j.jfa.2012.11.015}},
  volume       = {{264}},
  year         = {{2013}},
}