Claire Voisin

On a problem of Whitney type in algebraic geometry

CNRS, París Sorbonne

Whitney embedding theorem in differential geometry says that a small perturbation f’ of a map f between two manifolds of dimensions m and n (hence f’ is isotopic, and a fortiori homotopic to f) is an embedding if n>2m (the Whitney range). I will discuss a related question in complex algebraic geometry: can we write the cohomology class of an algebraic subvariety of a smooth projective variety as a combination with integral coefficients of classes of smooth subvarieties? The question is still open in the Whitney range.

Thursday, November 2, 9h30