Sur l'invariance topologique de la classe de Godbillon-Vey
Sur l'invariance topologique de la classe de Godbillon-Vey
The Godbillon-Vey invariant, classicaly defined for C 2 -foliations can also be defined for piecewise C 2 -foliations. We show that, in this extended category, the Godbillon-Vey invariant is not invariant under topological conjugation.