Gereon Quick:
Torsion algebraic cycles and etale cobordism
Abstract:
We show that the classical integral cycle class map from algebraic cycles
to étale cohomology factors through a quotient of l-adic étale cobordism
over an algebraically closed field of positive characteristic. This shows
that there is a strong topological obstruction for cohomology classes to
be
algebraic and that examples of Atiyah, Hirzebruch and Totaro also work in
positive characteristic.