The distance from the holomorphically decomposable Fredholm spectrum

Abdelaziz Tajmouati; Mohamed Baba Mohamed Ahmed; Abdeslam El Bakkali

doi:10.5269/bspm.v38i4.40247

The distance from the holomorphically decomposable Fredholm spectrum

Abdelaziz Tajmouati Sidi Mohamed Ben Abdellah University Faculty of Sciences Dhar Al Mahraz
Mohamed Baba Mohamed Ahmed Sidi Mohamed Ben Abdellah University Faculty of Sciences Dhar Al Mahraz
Abdeslam El Bakkali Chouaib Doukkali University Faculty of Sciences Department of Mathematics

DOI: https://doi.org/10.5269/bspm.v38i4.40247

Keywords: Fredholm operator, distance spectrum, holomorphically decomposable Fredholm operator

Abstract

The class of holomorphically decomposable Fredholm operators was introduced by A. Tajmouati and A. El Bakkali since subclass of Saphar operators. Several authors have been interested in the distance of spectrum associated with the different classes. Especially C. Schmöeger has calculated the distance of Saphar spectrum. For this reason, in this paper, we establish the distance of the holomorphically decomposable Fredholm spectrum.