English

Three-fold divisorial contractions to singularities of higher indices

Algebraic Geometry 2007-05-23 v1

Abstract

We complete the explicit study of a three-fold divisorial contraction whose exceptional divisor contracts to a point, by treating the case where the point downstairs is a singularity of index n2n \ge 2. We prove that if this singularity is of type cA/nA/n then any such contraction is a suitable weighted blow-up; and that if otherwise then the discrepancy is 1/n1/n with a few exceptions. Every such exception has an example. Some exceptions allow the discrepancy to be arbitrarily large, but any contraction in this case is described as a weighted blow-up of a singularity of type cD/2D/2 embedded into a cyclic quotient of a smooth five-fold. The erratum to the previous paper [14] is attached.

Keywords

Cite

@article{arxiv.math/0306065,
  title  = {Three-fold divisorial contractions to singularities of higher indices},
  author = {Masayuki Kawakita},
  journal= {arXiv preprint arXiv:math/0306065},
  year   = {2007}
}

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55 pages