The perturbation of the Drazin inverse and oblique projection (Q1588737)

The authors give lower and upper bounds of the norms of the Drazin inverse of matrices \(A\) and \(B\) with \(B=A+E\). Their evaluations imply as a corollary the criterion of the continuity of the Drazin inverse going back to \textit{S. L. Campbell} and \textit{C. D. Meyer} jun. [Linear Algebra Appl. 10, 77-83 (1975; Zbl 0301.15004)].