Sb. Edgar, CURVATURE COPIES AND THE UNIQUENESS OF BIANCHI-TYPE EQUATIONS - THE SYMMETRICAL CONNECTION CASE, Classical and quantum gravity, 10(12), 1993, pp. 2545-2555
It is shown, in general circumstances in a four-dimensional spacetime.
that (i) the symmetric metric connection of a Riemann tensor cannot b
e a curvature copy of a symmetric non-metric connection, (ii) the only
Bianchi-type equation (in a symmetric connection) obeyed by a Riemann
tensor is its own Bianchi equation. Further, these results for Rieman
n tensors (of metric connections) are generalized naturally to curvatu
re tensors of Weyl connections.