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STRICTLY SINGULAR PERTURBATION OF ALMOST SEMI-FREDHOLM LINEAR RELATIONS IN NORMED SPACES

Published online by Cambridge University Press:  13 August 2013

T. ÁLVAREZ
T. ÁLVAREZ*
Affiliation:
Department of Mathematics, University of Oviedo, C/Calvo Sotelo s/n, Oviedo 33007, Asturias, Spain e-mail: seco@uniovi.es
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Abstract

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In this paper, we introduce the notions of almost upper semi-Fredholm and strictly singular pairs of subspaces and show that the class of almost upper semi-Fredholm pairs of subspaces is stable under strictly singular pairs perturbation. We apply this perturbation result to investigate the stability of almost semi-Fredholm multi-valued linear operators in normed spaces under strictly singular perturbation as well as the behaviour of the index under perturbation.

Keywords

47A06
Type
Research Article
Information
Glasgow Mathematical Journal , Volume 56 , Issue 1 , January 2014 , pp. 211 - 219
Copyright
Copyright © Glasgow Mathematical Journal Trust 2013 

References

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