English

Purely log terminal threefolds with non-normal centres in characteristic two

Algebraic Geometry 2018-04-26 v2

Abstract

We show that many classical results of the minimal model programme do not hold over an algebraically closed field of characteristic two. Indeed, we construct a three dimensional plt pair whose codimension one part is not normal, a three dimensional klt singularity which is not rational nor Cohen-Macaulay, and a klt Fano threefold with non-trivial intermediate cohomology.

Keywords

Cite

@article{arxiv.1607.08590,
  title  = {Purely log terminal threefolds with non-normal centres in characteristic two},
  author = {Paolo Cascini and Hiromu Tanaka},
  journal= {arXiv preprint arXiv:1607.08590},
  year   = {2018}
}

Comments

38 pages. To appear in the American Journal of Mathematics