English

Construction of algebraic covers

Algebraic Geometry 2020-01-07 v3 Commutative Algebra

Abstract

Let YY be an algebraic variety, F\mathcal{F} a locally free sheaf of OY\mathcal{O}_Y-modules, and R(F)\mathcal{R}(\mathcal{F}) the OY\mathcal{O}_Y-algebra SymF\operatorname{Sym}^\bullet \mathcal{F}. In this paper we study local properties of sheaves of OR(F)\mathcal{O}_{\mathcal{R}(\mathcal{F})}-ideals I\mathcal{I} such that R(F))/I\mathcal{R}(\mathcal{F}))/\mathcal{I} is an algebraic cover of YY. Following the work of Miranda for triple covers, for Q\mathcal{Q} a direct summand of R(F)\mathcal{R}(\mathcal{F}), we say that a morphism Φ ⁣:QR(F)/Q\Phi\colon \mathcal{Q}\rightarrow\mathcal{R}(\mathcal{F})/\langle\mathcal{Q}\rangle is a covering homomorphism if it induces such an ideal. As an application we study in detail the case of Gorenstein covering maps of degree 66 for which the direct image of φOX\varphi_*\mathcal{O}_X admits an orthogonal decomposition. These are deformation of S3S_3-Galois branch covers.

Keywords

Cite

@article{arxiv.1709.03341,
  title  = {Construction of algebraic covers},
  author = {Eduardo Dias},
  journal= {arXiv preprint arXiv:1709.03341},
  year   = {2020}
}
R2 v1 2026-06-22T21:38:55.764Z