xAct-contrib/xPand — pull request #5 by CyrilPitrou (2013-11-12 01:04:57+00:00)
Title: Version 0.4.2 on its way. Implementation of the perturbation of normal vector

A small example has been added to show how one can perturb the normal vector.
More examples should come. Ideally one would like to treat the entire ADM formalism (with lapse and shift).