English

Unirationality and geometric unirationality for hypersurfaces in positive characteristics

Algebraic Geometry 2020-02-24 v1

Abstract

Building on work of Segre and Koll'ar on cubic hypersurfaces, we construct over imperfect fields of characteristic p\geq 3 particular hypersurfaces of degree p, which show that geometrically rational schemes that are regular and whose rational points are Zariski dense are not necessarily unirational. A likewise behaviour holds for certain cubic surfaces in characteristic p=2.

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Cite

@article{arxiv.2002.09228,
  title  = {Unirationality and geometric unirationality for hypersurfaces in positive characteristics},
  author = {Keiji Oguiso and Stefan Schröer},
  journal= {arXiv preprint arXiv:2002.09228},
  year   = {2020}
}

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16 pages