Editing Tensor field (section)

== Tensor calculus ==

In [[theoretical physics]] and other fields, [[differential equation]]s posed in terms of tensor fields provide a very general way to express relationships that are both geometric in nature (guaranteed by the tensor nature) and conventionally linked to [[differential calculus]]. Even to formulate such equations requires a fresh notion, the [[covariant derivative]]. This handles the formulation of variation of a tensor field ''along'' a [[vector field]]. The original ''absolute differential calculus'' notion, which was later called ''[[tensor calculus]]'', led to the isolation of the geometric concept of [[connection (differential geometry)|connection]].