English

The Brauer group and indecomposable (2,1)-cycles

Algebraic Geometry 2019-02-20 v3

Abstract

We show that the torsion in the group of indecomposable (2,1)(2,1)-cycles on a smooth projective variety over an algebraically closed field is isomorphic to a twist of its Brauer group, away from the characteristic. In particular, this group is infinite as soon as b2ρ>0b_2-\rho>0. We derive a new insight into Roitman's theorem on torsion 00-cycles over a surface.

Keywords

Cite

@article{arxiv.1401.0791,
  title  = {The Brauer group and indecomposable (2,1)-cycles},
  author = {Bruno Kahn},
  journal= {arXiv preprint arXiv:1401.0791},
  year   = {2019}
}

Comments

Final version, to appear in Compositio Math

R2 v1 2026-06-22T02:39:02.984Z