SortCovDs

• SortCovDs[expr,covd] exchange repeatedly two instances of the covariant derivative covd, introducing Riemann and Torsion tensors if needed, until the indices of the derivatives are sorted in canonical order.
• SortCovDs[expr,list] sorts sequentially the covariant derivatives in the list.
• SortCovDs[expr] sorts all the covariant derivatives in expr.

• Currently this function only works properly for abstract indices.
• The use of this function can be automatized with the pair SortCovDsStart / SortCovDsStop.
• See: Section 4.5.
• See also: CommuteCovDs.
• New in version 0.
• Last update: 15-X-2007 for version 0.9.3 of xTensor`.

Created by Mathematica  (May 16, 2008)