  Maxwell's equations are a system of partial differential equations that
govern the laws of electromagnetic induction. We study a mimetic
finite-difference (MFD) discretization of the equations which preserves
important underlying physical properties. We show that, after mass-lumping and
appropriate scaling, the MFD discretization is equivalent to a
structure-preserving finite-element (FE) scheme. This allows for a transparent
analysis of the MFD method using the FE framework, and provides an avenue for
the construction of efficient and robust linear solvers for the discretized
system. In particular, block preconditioners designed for FE formulations can
be applied to the MFD system in a straightforward fashion. We present numerical
tests which verify the accuracy of the MFD scheme and confirm the robustness of
the preconditioners.
