On the existence of a Gysin morphism for the Blow-up of an ordinary singularity

Abstract

In this paper we characterize the Blowing-up maps of ordinary singularities for which there exists a natural Gysin morphism, i.e. a bivariant class $$\theta \in Hom_{D(Y)}(R\pi _*\mathbb {Q}_X, \mathbb {Q}_Y)$$ , compatible with pullback and with restriction to the complement of the singularity.