Einstein, in his Generalized Theory of Gravitation [I], deals with a tensor
whose ninety-six independent components are complex-valued functions of four real variables xα. Schouten [4, p. 261 (89)] has decomposed the general relative tensor,
antisymmetric in α, β, γ, and in ρ,σ, into five irreducible parts. This decomposition can be applied to the R of Einstein if we define the tensor v by