Three-Dimensional Formulation of Gravitational Null Fields. II

Abstract

In the previous paper of this series, it was shown that three types of gravitational null fields may be characterized on the analogy of the electromagnetic field. The first two types were discussed in the previous paper. This paper discusses the remaining third type (C) of gravitational null field. The necessary and sufficient condition that the gravitational field be of type C is obtained. The formalism is also extended to include nonempty gravitational fields. It is shown that the nonempty space-time may also admit three types of gravitational null fields under certain circumstances. A typical case is discussed as an example.