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 ${\mathcal H}$-matrices. We prove that root exponential convergence in the block rank can be achieved if the block structure conforms to a standard admissibility criterion.

翻译：时间- 调和 Maxwell 方程式的坚硬度矩阵与 完全 运行边界条件的逆差, 以 $_mathcal H} $- maters 的块状低级格式为近似。 我们证明,如果区块结构符合标准可受理标准, 区块级的根指数趋同可以实现。