Un invariant d'isotopie lisse pour des surfaces dans une variété de dimension 4

We construct an invariant of smooth isotopy for surfaces smoothly embeded in 4-manifolds. This invariant is used to distinguish smooth embeddings of tori or Klein bottles that are regular homotopic in $\text{C}{}^1\text{×}\text{C}{}^1$, and that have the same complement and the same fundamental rack. To cite this article: C. Darolles, C. R. Acad. Sci. Paris, Ser. I 335 (2002) 811–815.