“…Then, a strategy for coupling such processes consists in coupling the driving noises and see the effects on the "driven processes". It gives numerous examples for couplings, successful or not [22,10,16,12,28,27,26,3,4,17,3,5]. This strategy can be used to study the subelliptic Brownian motion B t = (X t , z t ) for three model spaces of subRiemannian manifolds:…”