English

Functorial resolution except for toroidal locus. Toroidal compactification

Algebraic Geometry 2020-07-29 v1

Abstract

Let XX be any variety in characteristic zero. Let VXV \subset X be an open subset that has toroidal singularities. We show the existence of a canonical desingularization of XX except for V. It is a morphism f:YXf: Y \to X , which does not modify the subset V V and transforms XX into a toroidal embedding YY, with singularities extending those on VV. Moreover, the exceptional divisor has simple normal crossings on YY. The theorem naturally generalizes the Hironaka canonical desingularization. It does not modify the nonsingular locus VV and transforms XX into a nonsingular variety YY. The proof uses, in particular, the canonical desingularization of logarithmic varieties recently proved by Abramovich -Temkin-Wlodarczyk. It also relies on the established here canonical functorial desingularization of locally toric varieties with an unmodified open toroidal subset. As an application, we show the existence of a toroidal equisingular compactification of toroidal varieties. All the results here can be linked to a simple functorial combinatorial desingularization algorithm developed in this paper.

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Cite

@article{arxiv.2007.13846,
  title  = {Functorial resolution except for toroidal locus. Toroidal compactification},
  author = {Jarosław Włodarczyk},
  journal= {arXiv preprint arXiv:2007.13846},
  year   = {2020}
}

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82 pages