An analytic method in general relativity

An analytic method, which Wu called the “Bochner technique”, has been used for fifty years to describe global Riemannian and Kдhler geometries. We use this method to describe conformally Killing vector fields and harmonic timelike vector fields on a Lorentzian manifold and to study hydrodynamic models of the Universe, the existence of closed spacelike sections, and the possibility of fibering Lorentzian manifolds.