Alekseevskiy, Dmitry; Ganji, Masoud; Schmalz, Gerd; Spiro, Andrea
(ELSEVIER, 2021)
We study Lorentzian manifolds (M, g) of dimension n >= 4, equipped with a maximally twisting shearfree null vector field p, for which the leaf space S=M/{exptp} is a smooth manifold. If n = 2k, the quotient S = M/{exptp} ...