On solving Einstein's field equations in the Newman-Penrose formalism (Q1058156)

Using the Newman-Penrose formalism and Penrose's conformal rescaling a method is presented for finding systematically solutions (or, at least, reduced equations for) the general field equations. These solutions are necessarily (locally) asymptotically flat and are represented in a coordinate system based on a geodesic, twist-free, expanding null congruence. All redundant equations are disposed of and the freely specifiable data are clearly exhibited. Although the few equations that remain to be solved are, in general, intractable, well-known theorems guarantee the existence and uniqueness of solutions. The method applies to \({\mathcal H}\) spaces and \({\mathcal H}{\mathcal H}\) spaces as well as to real space-times.