English

On deformations of Q-Fano threefolds

Algebraic Geometry 2014-10-30 v6

Abstract

We study the deformation theory of a Q-Fano 3-fold with only terminal singularities. First, we show that the Kuranishi space of a Q-Fano 3-fold is smooth. Second, we show that every Q-Fano 3-fold with only "ordinary" terminal singularities is Q-smoothable, that is, it can be deformed to a Q-Fano 3-fold with only quotient singularities. Finally, we prove Q-smoothability of a Q-Fano 3-fold assuming the existence of a Du Val anticanonical element. As an application, we get the genus bound for primary Q-Fano 3-folds with Du Val anticanonical elements.

Keywords

Cite

@article{arxiv.1203.6323,
  title  = {On deformations of Q-Fano threefolds},
  author = {Taro Sano},
  journal= {arXiv preprint arXiv:1203.6323},
  year   = {2014}
}

Comments

29 pages. Title changed. Fixed a small problem on obstructions