English

Lifting Weighted Blow-ups

Algebraic Geometry 2017-02-16 v2

Abstract

Let f: X -> Z be a local, projective, divisorial contraction between normal varieties of dimension n with Q-factorial singularities. Let YXY \subset X be a f-ample Cartier divisor and assume that f|Y: Y -> W has a structure of a weighted blow-up. We prove that f: X -> Z, as well, has a structure of weighted blow-up. As an application we consider a local projective contraction f: X -> Z from a variety X with terminal Q-factorial singularities, which contracts a prime divisor E to an isolated Q-factorial singularity PZP\in Z, such that (KX+(n3)L)-(K_X + (n-3)L) is f-ample, for a f-ample Cartier divisor L on X. We prove that (Z,P) is a hyperquotient singularity and f is a weighted blow-up.

Keywords

Cite

@article{arxiv.1609.00156,
  title  = {Lifting Weighted Blow-ups},
  author = {Marco Andreatta},
  journal= {arXiv preprint arXiv:1609.00156},
  year   = {2017}
}

Comments

11 pages, minor issues corrected. To appear in Revista Matematica Iberoamericana

R2 v1 2026-06-22T15:37:27.640Z