A Posteriori Error Estimates for Elliptic Eigenvalue Problems Using Auxiliary Subspace Techniques

We propose an a posteriori error estimator for high-order p- or hp-finite element discretizations of selfadjoint linear elliptic eigenvalue problems that is appropriate estimating the in approximation cluster and corresponding invariant subspace. The based on computation approximate functions space complements one which eigenvectors were computed. These are used to construct estimates collective measures error, such as Hausdorff distance between true clusters eigenvalues, subspace gap subspaces. Numerical experiments demonstrate practical effectivity approach.