How to calculate covariant derivative by Mathematica?

*To*: mathgroup at smc.vnet.net*Subject*: [mg106778] How to calculate covariant derivative by Mathematica?*From*: Shen <zshen2002 at yahoo.com>*Date*: Sat, 23 Jan 2010 07:33:15 -0500 (EST)

I need to calculate covariant derivative by Mathematica. I noticed that there is no such a function in Mathematica. Can we define such a funcation? I don't know how to do it. Who can tell me how to define and calculate covariant derivative with Mathematica?