SortCovDs doesn't work in xFields

[Александр Куров]

Hello,

I work in xFields package and SortCovDs command doesn't work for the bundle derivatives, DD, while it works as usual for covariant derivatives on the manifold, CD. What could be the problem?

Best, Sasha 

[Markus B. Fröb]

Dear Sasha,

you have to use

DefCovD[DD[-i], lie, {":", "D"}, FromMetric -> metric];

to tell xAct that the indices of DD can be raised with the tangent
space metric. Otherwise, covariant derivatives can only be commuted if
they have covariant abstract indices.

Best, Markus


Zitat von Александр Куров <kurov.a...@physics.msu.ru>: