On the Point Spectrum of Self-Adjoint Operators That Appears under Singular Perturbations of Finite Rank

2003 ◽  
Vol 55 (9) ◽  
pp. 1532-1541 ◽  
Author(s):  
M. E. Dudkin ◽  
V. D. Koshmanenko
1997 ◽  
Vol 49 (9) ◽  
pp. 1335-1344 ◽  
Author(s):  
V. D. Koshmanenko ◽  
O. V. Samoilenko

2003 ◽  
Vol 6 (4) ◽  
pp. 349-384 ◽  
Author(s):  
Vladimir Derkach ◽  
Seppo Hassi ◽  
Henk de Snoo

1984 ◽  
Vol 36 (1) ◽  
pp. 5-9
Author(s):  
M. Wollenberg ◽  
H. Neidhardt ◽  
V. D. Koshmanenko

2007 ◽  
Vol 280 (1-2) ◽  
pp. 20-27 ◽  
Author(s):  
Sergio Albeverio ◽  
Mykola Dudkin ◽  
Alexei Konstantinov ◽  
Volodymyr Koshmanenko

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Qingping Zeng ◽  
Huaijie Zhong

An operatorT∈ℬ(X)defined on a Banach spaceXsatisfies property(gb)if the complement in the approximate point spectrumσa(T)of the upper semi-B-Weyl spectrumσSBF+-(T)coincides with the setΠ(T)of all poles of the resolvent ofT. In this paper, we continue to study property(gb)and the stability of it, for a bounded linear operatorTacting on a Banach space, under perturbations by nilpotent operators, by finite rank operators, and by quasinilpotent operators commuting withT. Two counterexamples show that property(gb)in general is not preserved under commuting quasi-nilpotent perturbations or commuting finite rank perturbations.


2021 ◽  
Vol 9 (1) ◽  
pp. 140-151
Author(s):  
O. Dyuzhenkova ◽  
M. Dudkin

The singular nonsymmetric rank one perturbation of a self-adjoint operator from classes ${\mathcal H}_{-1}$ and ${\mathcal H}_{-2}$ was considered for the first time in works by Dudkin M.E. and Vdovenko T.I. \cite{k8,k9}. In the mentioned papers, some properties of the point spectrum are described, which occur during such perturbations. This paper proposes generalizations of the results presented in \cite{k8,k9} and \cite{k2} in the case of nonsymmetric class ${\mathcal H}_{-2}$ perturbations of finite rank. That is, the formal expression of the following is considered \begin{equation*} \tilde A=A+\sum \limits_{j=1}^{n}\alpha_j\langle\cdot,\omega_j\rangle\delta_j, \end{equation*} where $A$ is an unperturbed self-adjoint operator on a separable Hilbert space ${\mathcal H}$, $\alpha_j\in{\mathbb C}$, $\omega_j$, $\delta_j$, $j=1,2, ..., n<\infty$ are vectors from the negative space ${\mathcal H}_{-2}$ constructed by the operator $A$, $\langle\cdot,\cdot\rangle$ is the dual scalar product between positive and negative spaces.


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