  A singular foliation in the sense of Androulidakis and Skandalis is an
involutive and locally finitely generated module of compactly supported vector
fields on a manifold. An automorphism of a singular foliation is a
diffeomorphism that preserves the module. In this note, we give an alternative
proof of the (surprisingly non-trivial) fundamental fact that the time-one flow
of an element of a singular foliation (i.e. its exponential) is an automorphism
of the singular foliation.
