New decompositions for the classes of quasi-Fredholm and semi B-Weyl operators

Abstract:

In this paper, we show that if T ϵL(X) is a quasi-Fredholm operator of degree d such that N(Td)+R(T) is complemented, then T has a decomposition like the Kato type operators. Using this decomposition allows us get a result about the stability of this class of operators under perturbations by nilpotent operators. Also we give a new decomposition for the class of semi B-Weyl operators, and through this property we shown that T is a semi B-Weyl operator if and only if T=S+K where S is a semi B-Browder operator and K is finite-dimensional.

Año de publicación:

2020

Keywords:

• nilpotent operator
• Perturbation
• Quasi-Fredholm operator
• decomposition

Fuente:

scopus