Abstract
Rayleigh–Schrödinger series for perturbation bounds of spectral elements is revisited. The convergence radius is estimated for bases of spectral subspaces. Applications to both Hessenberg and Hermitian matrices are developed, which are useful in spectral approximation with numerical methods.
ACKNOWLEDGMENT
This research was partially supported by the Belgian Fonds de la Recherche Scientifique (FNRS) during 2007 at the Facultés universitaires catholiques de Mons (FUCaM).