$${\mathcal{H}}$$-matrix approximability of inverses of FEM matrices for the time-harmonic Maxwell equations
$${\mathcal{H}}$$-matrix approximability of inverses of FEM matrices for the time-harmonic Maxwell equations
Abstract The 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 $${\mathcal{H}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>H</mml:mi> </mml:math> -matrices. Under a technical assumption on the mesh, we prove that root exponential convergence in the block rank can be …