GIT stable cubic threefolds and certain fourfolds of $K3^{[2]}$-type

Fuente: arXiv
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Autore principale: Bassi, Lucas Li
Natura: Preprint
Pubblicazione: 2023
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author Bassi, Lucas Li
author_facet Bassi, Lucas Li
contents We study the behaviour on some nodal hyperplanes of the isomorphism, described in a paper of 2019 by Boissière, Camere and Sarti, between the moduli space of smooth cubic threefolds and the moduli space of hyperkähler fourfolds of $K3^{[2]}$-type with a non-symplectic automorphism of order three, whose invariant lattice has rank one and is generated by a class of square 6; along those hyperplanes the automorphism degenerates by jumping to another family. We generalize their result to singular nodal cubic threefolds having one singularity of type $A_i$ for $i=2, 3, 4$ providing birational maps between the loci of cubic threefolds where a generic element has an isolated singularity of the types $A_i$ and some moduli spaces of hyperkähler fourfolds of $K3^{[2]}$-type with non-symplectic automorphism of order three belonging to different families. In order to treat the $A_2$ case, we introduce the notion of Kähler cone sections of $K$-type generalizing the definition of $K$-general polarized hyperkähler manifolds.
format Preprint
id arxiv_https___arxiv_org_abs_2301_11149
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle GIT stable cubic threefolds and certain fourfolds of $K3^{[2]}$-type
Bassi, Lucas Li
Algebraic Geometry
14J17, 14J30, 14J42, 14J50
We study the behaviour on some nodal hyperplanes of the isomorphism, described in a paper of 2019 by Boissière, Camere and Sarti, between the moduli space of smooth cubic threefolds and the moduli space of hyperkähler fourfolds of $K3^{[2]}$-type with a non-symplectic automorphism of order three, whose invariant lattice has rank one and is generated by a class of square 6; along those hyperplanes the automorphism degenerates by jumping to another family. We generalize their result to singular nodal cubic threefolds having one singularity of type $A_i$ for $i=2, 3, 4$ providing birational maps between the loci of cubic threefolds where a generic element has an isolated singularity of the types $A_i$ and some moduli spaces of hyperkähler fourfolds of $K3^{[2]}$-type with non-symplectic automorphism of order three belonging to different families. In order to treat the $A_2$ case, we introduce the notion of Kähler cone sections of $K$-type generalizing the definition of $K$-general polarized hyperkähler manifolds.
title GIT stable cubic threefolds and certain fourfolds of $K3^{[2]}$-type
topic Algebraic Geometry
14J17, 14J30, 14J42, 14J50
url https://arxiv.org/abs/2301.11149