On the perturbation of semi-Fredholm relations with complemented ranges and null spaces
The author gives a multivalued version of a compact additive perturbation result of closed operators acting on Banach spaces. The proof is different to the one used in the corresponding single-valued version. Multivalued semi-Fredholm type linear operators with complemented ranges and null spaces are introduced. Conditions are obtained under which the classes given are stable under compact, strictly singular and cosingular additive perturbations.
scientific article; zbMATH DE number 5816574
scientific article