English

The perturbation classes problem for subprojective and superprojective Banach spaces

Functional Analysis 2020-06-11 v1

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.

Keywords

Cite

@article{arxiv.2006.05802,
  title  = {The perturbation classes problem for subprojective and superprojective Banach spaces},
  author = {Manuel González and Javier Pello and Margot Salas-Brown},
  journal= {arXiv preprint arXiv:2006.05802},
  year   = {2020}
}

Comments

6 pages

R2 v1 2026-06-23T16:12:24.762Z