OverDot

• OverDot[expr] represents a simple ordinary derivative of expr with respect to some internal parameter (say time) which is independent of the coordinates of the manifolds where expr lives.

• This is kept for backwards compatibility, but now we recommend to change to the more flexible parametric derivative ParamD.
• It commutes with partial derivatives, but not with covariant derivatives or with Lie derivatives because in general the vector field of the Lie derivative could depend upon the parameter as well.
• See: Section 4.8.
• New in version 0.
• Last update: 25-X-2007 for version 0.9.3 of xTensor`.

Created by Mathematica  (May 16, 2008)