$${\mathcal{H}}$$-matrix approximability of inverses of FEM matrices for the time-harmonic Maxwell equations

Abstract

AbstractThe inverse of the stiffness matrix of the time-harmonic Maxwell equation with perfectly conducting boundary conditions is approximated in the blockwise low-rank format of $${\mathcal{H}}$$ H -matrices. Under a technical assumption on the mesh, we prove that root exponential convergence in the block rank can be achieved, if the block structure conforms to a standard admissibility criterion.