@article{10902/32434,
year = {2020},
month = {9},
url = {https://hdl.handle.net/10902/32434},
abstract = {We show that the perturbation class for the upper semi-Fredholm operators between two Banach spaces X and Y coincides with the strictly singular operators when X is subprojective and that the perturbation class for the lower semi-Fredholm operators coincides with the strictly cosingular operators when Y is superprojective. Similar results were previously obtained under stronger conditions for X and Y.},
publisher = {Academic Press Inc.},
publisher = {Journal of Mathematical Analysis and Applications, 2021, 489 (2), 124191},
title = {The perturbation classes problem for subprojective and superprojective Banach spaces},
author = {González Ortiz, Manuel and Pello García, Javier and Salas-Brown, M.},
}