Preliminaries
Riemannian metrics, R manifolds, local diffeomorphisms, Every smooth manifold admits a riemannian metric, the space of riemannian metrics on is infinite dimensional. Whitney embedding theorem (every smooth manifold is diffeomorphic to an embedded submanifold of an Euclidean space), Nash (every riemannian manifold can be embedded into such that ). Product of manifolds, warp products