ABSTRACT
We define the surface impedance tensor for the general second order elliptic system in a two-dimensional space. We show that this tensor is invariant with respect to the rotation in the plane. Next, we construct the solution to the Dirichlet problem of this system in the infinite plane region with an elliptic hole and we observe that the correspondence between the Dirichlet data and the Neumann data on the boundary is written in a closed form by using the surface impedance tensor. This article is a survey of the results in [Ta2]. In addtion, we give some remarks on the roles of the surface impedance tensor in the inverse boundary value problems.
