Curvature Tensor

[dr. undefined]

Do you agree with the fact that Einstein introduced the curvature tensor taking it 0 to be legit?

[Aethelwulf]

Do you agree with the fact that Einstein introduced the curvature tensor taking it 0 to be legit?

 

When is it taken to be zero?

[elfmotat]

Which curvature tensor (Riemann, Ricci, Weyl)? And in what situation? In a vacuum where T_ab=0, then by the field equations you get R_ab=0. So in a vacuum the Ricci tensor vanishes. On the other hand, the Riemann and Weyl tensors do not generally vanish.