Uniqueness in inverse obstacle scattering with conductive boundary condition

Using Isakov's approach to uniqueness in inverse scattering, Hettlich has obtained a uniqueness result for the conductive boundary condition via weak solutions. Following ideas of Kirsch and Kress, using an integral equation approach in the present paper we give a simplified proof for Hettlich's uniqueness theorem which also includes a simpler version of the uniqueness proof of Kirsch and Kress for the transmission problem.