On the perturbation of the group inverse and oblique projection

摘要

For given matrices A and E which are n matrices and matrices and E, we discuss upper bounds for ∥B#∥, ∥BB#∥, ∥B# −A#∥/∥A#∥ and ∥BB# −AA#∥/∥AA#∥, also a lower bound for ∥B#∥ is derived.