Simultaneous versal deformations of endomorphisms and invariant subspaces

Abstract We study the set M of pairs ( f ,  V ), defined by an endomorphism f of F n and a d -dimensional f -invariant subspace V . It is shown that this set is a smooth manifold that defines a vector bundle on the Grassmann manifold. We apply this study to derive conditions for the Lipschitz stability of invariant subspaces and determine versal deformations of the elements of M with respect to a natural equivalence relation introduced on it.