Equivalence of Nondifferentiable Metrics

We study nondifferentiable metrics occuring in general relativity via the method of equivalence of Cartan adapted to the Courant algebroids. We derive new local differential invariants naturally associated with the loci of nondifferentiability and rank deficiency of the metric. As an application, we utilize the newfangled invariants to resolve the problem of causality in the interior of the black holes that contain closed timelike geodesics. Also, a no-go type theorem limits the evolution scenarios for gravitational collapse.