The construction of a complete set of quantities in general relativity, whose functional form is invariant under coordinate transformations, is indicated. The set obtained is highly redundant. The Cauchy problem for obtaining an independent complete set of such quantities ("observables") is therefore discussed. It is also pointed out that the observables obtained may alternatively be viewed as the metric tensor in a special "gauge" (i.e., with a special coordinate condition). This latter viewpoint may facilitate the quantization of general relativity.

• Received 7 April 1958

DOI:https://doi.org/10.1103/PhysRev.111.1182