Uniqueness for inverse boundary value problems by Dirichlet-to -Neumann map on subboundaries

Abstract

We consider inverse boundary value problems for elliptic equations of second order of determining coefficients by Dirichlet-to-Neumann map on subboundaries, that is, the mapping from Dirichlet data supported on $\partialΩ\setminus Γ_-$ to Neumann data on $\partialΩ\setminus Γ_+$. First we prove uniqueness results in three dimensions under some conditions such as $\bar{Γ_+ \cup Γ_-} = \partialΩ$. Next we survey uniqueness results in two dimensions for various elliptic systems for arbitrarily given $Γ_- = Γ_+$. Our proof is based on complex geometric optics solutions which are constructed by a Carleman estimate.