Unique continuation for solutions to Maxwell’s system with non-analytic anisotropic coefficients

We consider Maxwell’s system with anisotropic coefficients, i.e., the electric permittivity and the magnetic permeability are assumed to be matrices with non-analytic entries. Under the additional assumption that one matrix is a scalar multiple of the other we prove unique continuation of the system across non-characteristic surfaces. The proof relies on differential geometry as well as on Carleman estimates.  2003 Elsevier Inc. All rights reserved.