Ricci curvature
2-TENSOR OBTAINED AS A CONTRACTION OF THE RIEMAN CURVATURE 4-TENSOR ON A RIEMANNIAN MANIFOLD (OR, MORE GENERALLY, A SMOOTH MANIFOLD EQUIPPED WITH AFFINE CONNECTION)
Ricci-curvature; Ricci curvature tensor; Ricci tensor; Trace-free Ricci tensor; Ricci form; Ricci Curvature
In differential geometry, the Ricci curvature tensor, named after Gregorio Ricci-Curbastro, is a geometric object which is determined by a choice of Riemannian or pseudo-Riemannian metric on a manifold. It can be considered, broadly, as a measure of the degree to which the geometry of a given metric tensor differs locally from that of ordinary Euclidean space or pseudo-Euclidean space.