CommuteCovDs

• CommuteCovDs[expr,covd,{a , b}] changes the order of derivatives covd[b][covd[a][...]] into covd[a][covd[b][...]] in expr, introducing as many Riemann and Torsion tensors as needed.

• The order of indices in the third argument is essential. Only when it is correct the function will do its job.
• Indices a, b can be of any type (including basis indices) and character (even if they have been raised with a metric which is not compatible with covd.
• See: Section 4.5.
• See also: SortCovDs.
• New in version 0.
• Last update: 21-X-2007 for version 0.9.3 of xTensor`.

Created by Mathematica  (May 16, 2008)