Communications of the
Korean Mathematical Society CKMS

We give a new characterization of Browder's theorem through equality between the pseudo B-Weyl spectrum and the generalized Drazin spectrum. Also, we will give conditions under which pseudo B-Fredholm and pseudo B-Weyl spectrum introduced in \cite{BO} and \cite{ZZ} become stable under commuting Riesz perturbations.

Keywords: generalized Kato decomposition, pseudo B-Fredholm operator, Browder's theorem, Riesz operator, commuting perturbation

MSC numbers: 47A53, 47B10