DOUBLE PARAMETRIZATION IN GENERAL-RELATIV ITY

We consider a five-dimensional manifold with two time-like dimensions. The three-dimensional space-like section is supposed to be flat and t he arbitrary functions present in the model are double-parametrized by the two time-like coordinates. The Einstein like equations in vacuum or in presence of a five-dimensional ''electromagnetic'' field are int egrated by using method of the separation of variables. A comparison i s made with the solutions that can be obtained if the fifth dimension is space-like, as is assumed in the usual Kaluza-Klein theories.