Algebraic hulls and smooth orbit equivalence

Abstract

For i = 1 , 2 , i = 1,2, let F i {\mathcal {F}_i} be foliations on smooth manifolds M i {M_i} determined by the actions of connected Lie groups H i {H_i} ; we describe here some results which provide an obstruction, in terms of a geometric invariant of the actions, to the existence of a diffeomorphism between the F i ′ s \mathcal {F}_i’{\text {s}} .