@Article{Gil2015,
author = "Gil', Michael",
title = "Simple eigenvectors of unbounded operators of the type \"normal plus compact\"",
journal = "Opuscula Math.",
year = "2015",
volume = "35",
number = "2",
pages = "161--169",
doi = "http://dx.doi.org/10.7494/OpMath.2015.35.2.161",
url = "http://dx.doi.org/10.7494/OpMath.2015.35.2.161",
abstract = "The paper deals with operators of the form \(A=S+B\), where \(B\) is a compact operator in a Hilbert space \(H\) and \(S\) is an unbounded normal one in \(H\), having a compact resolvent. We consider approximations of the eigenvectors of \(A\), corresponding to simple eigenvalues by the eigenvectors of the operators \(A_n=S+B_n\) (\(n=1,2, \ldots\)), where \(B_n\) is an \(n\)-dimensional operator. In addition, we obtain the error estimate of the approximation.",
keywords = "Hilbert space, linear operators, eigenvectors, approximation, integro-differential operators, Schatten-von Neumann operators",
issn = "1232-9274"
}