Differentiability of the g-Drazin inverse
نویسندگان
چکیده
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 AD(z) 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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