Tangent bundles to sub-Riemannian groups

This paper is about non-Euclidean analysis on Lie groups endowed with left invariant distributions, seen as sub-Riemannian manifolds. This is a an updated version, which will be modified according to the contributions of the other participants to the Borel Seminar. The current version can be downloaded at http://irmi.epfl.ch/cag/buliga_sr.html . All comments are welcomed.