English

On the integral Hodge conjecture for real varieties, II

Algebraic Geometry 2020-10-20 v3

Abstract

We establish the real integral Hodge conjecture for 1-cycles on various classes of uniruled threefolds (conic bundles, Fano threefolds with no real point, some del Pezzo fibrations) and on conic bundles over higher-dimensional bases which themselves satisfy the real integral Hodge conjecture for 1-cycles. In addition, we show that rationally connected threefolds over non-archimedean real closed fields do not satisfy the real integral Hodge conjecture in general and that over such fields, Br\"ocker's EPT theorem remains true for simply connected surfaces of geometric genus zero but fails for some K3 surfaces.

Keywords

Cite

@article{arxiv.1801.00873,
  title  = {On the integral Hodge conjecture for real varieties, II},
  author = {Olivier Benoist and Olivier Wittenberg},
  journal= {arXiv preprint arXiv:1801.00873},
  year   = {2020}
}

Comments

57 pages; v2: minor modifications, extended introduction; v3: Theorem 9.23 extended to higher dimension