English

On Q-Fano threefolds of Fano index 2

Algebraic Geometry 2016-06-29 v3

Abstract

We show that, for a Q-Fano threefold X of Fano index 2, the inequality dim |-1/2K_X| <= 4 holds with a single well understood family of varieties having dim |-1/2K_X| = 4.

Keywords

Cite

@article{arxiv.1203.0852,
  title  = {On Q-Fano threefolds of Fano index 2},
  author = {Yuri Prokhorov and Miles Reid},
  journal= {arXiv preprint arXiv:1203.0852},
  year   = {2016}
}

Comments

Minor changes, mostly biographical, to bring into line with the published version in Minimal Models and Extremal Rays (Kyoto 2011), Advanced Studies in Pure Mathematics 70, 2016, pp. 397--420