Fundamental theorem of Riemannian geometry
UNIQUE EXISTENCE OF THE LEVI-CIVITA CONNECTION
Fundamental theorem of riemannian geometry; Koszul formula
In the mathematical field of Riemannian geometry, the fundamental theorem of Riemannian geometry states that on any Riemannian manifold (or pseudo-Riemannian manifold) there is a unique affine connection which is torsion-free and metric-compatible, called the Levi-Civita connection or Riemannian connection of the given metric. Because it is canonically defined by such properties, often this connection is automatically used when given a metric.