Fr.: scalaire de Ricci
The simplest curvature invariant for a → Riemannian manifold. It is derived from the → Ricci tensor Rμν ≡ Rαμαν by contracting indices. Taking the trace of the Ricci tensor gives the Ricci scalar: R ≡ Rμνgμnu; = Rμν = Rαμαμ. Also called → scalar curvature.