Un critère d'extension d'un foncteur défini sur les schémas lisses

Abstract

Let $k$ be a field of characteristic zero. By using Hironaka's desingularisation theorem, we prove an extension criterion for a functor defined on nonsingular k-schemes and taking values on a category of complexes. Roughly speaking, the criterion shows that if such a functor satisfies the standard exact sequence of a blowing-up, then the functor can be extended to all separated k-schemes of finite type. The result is applied to the Grothendieck's theory of motives, to the Hodge-De Rham filtered complex of an analytic space, and to the rational homotopy of k-schemes in algebraic De Rham theory.