4 papers
Perturbations not necessarily commutative
Zakariae Aznay, Abdelmalek Ouahab, Hassan Zariouh
This paper treatises the preservation of some spectra under perturbations not necessarily commutative and generalizes several results which have been proved in the case of commutin…
Generalization of some commutative perturbation results
Zakariae Aznay, Abdelmalek Ouahab, Hassan Zariouh
We study the stability of certain spectra under some algebraic conditions weaker than the commutativity and we generalize many known commutative perturbation results.
Generalization of Kato's decomposition
Zakariae Aznay, Abdelmalek Ouahab, Hassan Zariouh
The Kato's decomposition \cite[Theorem 4]{kato} is generalized to semi-B-Fredholm operators.
On subclasses of Browder and Weyl operators
Zakariae Aznay, Abdelmalek Ouahab, Hassan Zariouh
The main purpose of this paper, is to introduce and study the classes and which are strongly related to what has been recently studied in \cite{aznay-zariouh}…