A new class of vacuum solutions of the Einstein field equations

TheKerr solution is today textbookmaterial and a basic element of education in relativity. However, derivations of it are not easy to find in the literature—most textbooks and monographs simply quote it as a given thing. There exist several uniqueness theorems (see part 2 of this note) that refer to physical and geometrical properties of the Kerr solution, but none of them gives a hint on how to derive it starting from the Einstein