On the essential approximate point spectrum II
We study the continuity of the generalized Drazin inverse for elements of Banach algebras and bounded linear operators on Banach spaces. This work extends the results obtained by the second author on the conventional Drazin inverse.
In this paper we investigate linear operators between arbitrary BK spaces and spaces of sequences that are summable or bounded. We give necessary and sufficient conditions for infinite matrices to map into . Further, the Hausdorff measure of noncompactness is applied to give necessary and sufficient conditions for to be a compact operator.
If A(z) is a function of a real or complex variable with values in the space B(X) of all bounded linear operators on a Banach space X with each A(z)g-Drazin invertible, we study conditions under which the g-Drazin inverse is differentiable. From our results we recover a theorem due to Campbell on the differentiability of the Drazin inverse of a matrix-valued function and a result on differentiation of the Moore-Penrose inverse in Hilbert spaces.
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