The Calderón problem with partial data

Abstract

In this paper we improve an earlier result by Bukhgeim and Uhlmann, by showing that in dimension larger than or equal to three, the knowledge of the Cauchy data for the Schrödinger equation measured on possibly very small subsets of the boundary determines uniquely the potential. We follow the general strategy of Bukhgeim and Uhlmann but use a richer set of solutions to the Dirichlet problem.

Revised version (Nov 5, 2004) fixing a mistake in section 6 and adding an application to the original problem for the conductivity. Revised version (Sept 14, 2005) modifying a few lines in the introduction and correcting the formula (1.8)