Koszul formula (source code)

= Koszul formula
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The unique torsion-free metric connection satisfies
$$
2g(\nabla_XY,Z)
=Xg(Y,Z)+Yg(Z,X)-Zg(X,Y)
-g(X,[Y,Z])+g(Y,[Z,X])+g(Z,[X,Y]).
$$
This formula both proves uniqueness of the <Levi-Civita connection> and computes it from the metric and <Lie bracket of vector fields>.