Matematičeskie zametki, Tome 18 (1975) no. 4, pp. 601-607
Citer cet article
L. N. Nikol'skaya. Criteria for stability of the point spectrum under completely continuous perturbations. Matematičeskie zametki, Tome 18 (1975) no. 4, pp. 601-607. http://geodesic.mathdoc.fr/item/MZM_1975_18_4_a13/
@article{MZM_1975_18_4_a13,
author = {L. N. Nikol'skaya},
title = {Criteria for stability of the point spectrum under completely continuous perturbations},
journal = {Matemati\v{c}eskie zametki},
pages = {601--607},
year = {1975},
volume = {18},
number = {4},
language = {ru},
url = {http://geodesic.mathdoc.fr/item/MZM_1975_18_4_a13/}
}
TY - JOUR
AU - L. N. Nikol'skaya
TI - Criteria for stability of the point spectrum under completely continuous perturbations
JO - Matematičeskie zametki
PY - 1975
SP - 601
EP - 607
VL - 18
IS - 4
UR - http://geodesic.mathdoc.fr/item/MZM_1975_18_4_a13/
LA - ru
ID - MZM_1975_18_4_a13
ER -
%0 Journal Article
%A L. N. Nikol'skaya
%T Criteria for stability of the point spectrum under completely continuous perturbations
%J Matematičeskie zametki
%D 1975
%P 601-607
%V 18
%N 4
%U http://geodesic.mathdoc.fr/item/MZM_1975_18_4_a13/
%G ru
%F MZM_1975_18_4_a13
We show that a number $\lambda$ is an eigenvalue of the operator $T+C$ for an arbitrary compact perturbation $C$ if and only if the operator $T-\lambda I$ is semi-Fredholm and $\mathrm{ind}\,(T-\lambda I)>0$.
