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

Research paper by Paolo Cascini, Hiromu Tanaka

Indexed on: 28 Jul '16Published on: 28 Jul '16Published in: Mathematics - Algebraic Geometry



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.