Integral representation of the Drazin inverse

  title={Integral representation of the Drazin inverse},
  author={Nieves Castro Gonz{\'a}lez and Jerry J. Koliha and Yimin Wei},
for those singular matrices whose nonzero eigenvalues lie in the open right halfplane and for which ind(A) = 1; here A is the eigenprojection of A corresponding to the eigenvalue 0. Recall that ind(A), the index of A, is the least nonnegative k for which the nullspace of A coincides with the nullspace of A. Recently, Castro, Koliha and Wei [1, Corollary 2.5] obtained a simple integral representation of the Drazin inverse A for matrices A ∈ Cn×n (and more generally elements of a Banach algebra… CONTINUE READING