Metric tensor Created 2026-09-24 Updated 2026-09-24
A metric tensor is a nondegenerate symmetric covariant tensor that defines squared line elements by .
A type covariant tensor is a multilinear form on vectors. For arbitrary , the pullback of a covariant tensor is
Projection of all covariant slots means . Since every pushed-forward vector is already tangential,
Equality on all arguments proves . No antisymmetry is needed: this holds for every covariant tensor, not only for differential forms.