Some results on the stability of σeap(:) and σeδ(:) of linear relations

Aymen Ammar, Slim Fakhfakh, Aref jeribi


In this research paper, we provide firstly the necessary and sufficient
conditions for the algebraic sum to become a closed and closable linear
relation. Secondly, we investigate the stability of the essential approximate
point spectrum σeap(:) as well as the essential defect spectrum σeδ(T ), in
terms of linear relations on Banach spaces, which were introduced by T.
Àlvarez and all in [1].

Full Text:



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