English

$\mathbb{Z}/2\mathbb{Z}$-Equivariant smoothings of cusp singularities

Algebraic Geometry 2022-01-11 v1

Abstract

Let pXp\in X be the germ of a cusp singularity and let ι\iota be an antisymplectic involution, that is an involution such that there exists a nowhere vanishing holomorphic 2-form Ω\Omega on X{p}X\setminus \{p\} for which ι(Ω)=Ω\iota^*(\Omega)=-\Omega. Assume also that the involution is fixed point free on X{p}X\setminus\{p\}. We prove that a sufficient condition for such a singularity equipped with an antisymplectic involution to be equivariantly smoothable is the existence of a Looijenga (or anticanonical) pair (Y,D)(Y,D) that admits an involution free on YDY\setminus D and that reverses the orientation of DD. This work also contains the proof of an analogue necessary and sufficient condition for the Z/2Z\mathbb{Z}/2\mathbb{Z}-equivariant smoothability of simple elliptic singularities pC(E)p\in C(E) with EE an elliptic curve of degree d8d\leq 8 and even equipped with a Z/2Z\mathbb{Z}/2\mathbb{Z}-action.

Keywords

Cite

@article{arxiv.2201.02871,
  title  = {$\mathbb{Z}/2\mathbb{Z}$-Equivariant smoothings of cusp singularities},
  author = {Angelica Simonetti},
  journal= {arXiv preprint arXiv:2201.02871},
  year   = {2022}
}

Comments

Comments welcome!

R2 v1 2026-06-24T08:43:45.517Z