Local lens rigidity with incomplete data for a class of non-simple Riemannian manifolds

Abstract

Let $σ$ be the scattering relation on a compact Riemannian manifold $M$ with non-necessarily convex boundary, that maps initial points of geodesic rays on the boundary and initial directions to the outgoing point on the boundary and the outgoing direction. Let $\ell$ be the length of that geodesic ray. We study the question of whether the metric $g$ is uniquely determined, up to an isometry, by knowledge of $σ$ and $\ell$ restricted on some subset $D$. We allow possible conjugate points but we assume that the conormal bundle of the geodesics issued from $D$ covers $T^*M$; and that those geodesics have no conjugate points. Under an additional topological assumption, we prove that $σ$ and $\ell$ restricted to $D$ uniquely recover an isometric copy of $g$ locally near generic metrics, and in particular, near real analytic ones.