Some remarks on spectral approximation for compact operators

Finite-dimensional approximations for linear compact operators are constructed by discretization of the underlying Banach space. Sufficient conditions for strong convergence of the finite-dimensional operators to the given compact operator and for their collective compactness are obtained. In particular, the finite-dimensional approximation of the pencil A−λJ:H→V is considered, where H,V are Banach spaces, A is an invertible and J a compact operator.