Stitching Data: Recovering a Manifold's Geometry from Geodesic Intersections

Abstract

Let $(M,g)$ be a Riemannian manifold with boundary. We show that knowledge of the length of each geodesic, and where pairwise intersections occur along the corresponding geodesics allows for recovery of the geometry of $(M,g)$ (assuming $(M,g)$ admits a Riemannian collar of a uniform radius). We call this knowledge the 'stitching data'. We then pose a boundary measurement type problem called the 'delayed collision data problem' and apply our first result about the stitching data to recover the geometry from the collision data (with some reasonable geometric restrictions on the manifold).