Best Fredholm perturbation theorems
B-Fredholm and Drazin invertible operators through localized SVEP
Let be a Banach space and be a bounded linear operator on . We denote by the set of all complex such that does not have the single-valued extension property at . In this note we prove equality up to between the left Drazin spectrum, the upper semi-B-Fredholm spectrum and the semi-essential approximate point spectrum. As applications, we investigate generalized Weyl’s theorem for operator matrices and multiplier operators.
Bifurcation for the solutions of equations involving set valued mappings.
Browder's theorems and the spectral mapping theorem.