Picard groups of completed period images and the Deng-Robles problem

Fuente: arXiv
Gespeichert in:
Bibliographische Detailangaben
Hauptverfasser: Mounda, Badre, Zheng, Dongzhe
Format: Preprint
Veröffentlicht: 2026
Schlagworte:
Online-Zugang:
Tags: Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
_version_ 1866911503235416064
author Mounda, Badre
Zheng, Dongzhe
author_facet Mounda, Badre
Zheng, Dongzhe
contents A basic problem in the geometry of degenerating period maps is to determine whether their completed images admit an intrinsic algebraic description. For polarized variations of Hodge structure over smooth quasi-projective surfaces, Deng and Robles formulated such a problem in terms of the Kato-Nakayama-Usui completion of the period image and a conjectural Proj description involving the augmented Hodge line bundle and the boundary divisor on a smooth compactification of the base. We show that the essential obstruction to this description is divisor-theoretic: it may be expressed as a Picard-generation statement on the completed mixed period image. We prove this statement when the pure period image is one-dimensional, and consequently obtain the Deng-Robles Proj description in this case.
format Preprint
id arxiv_https___arxiv_org_abs_2603_09709
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Picard groups of completed period images and the Deng-Robles problem
Mounda, Badre
Zheng, Dongzhe
Algebraic Geometry
14D07, 32G20, 14C20
A basic problem in the geometry of degenerating period maps is to determine whether their completed images admit an intrinsic algebraic description. For polarized variations of Hodge structure over smooth quasi-projective surfaces, Deng and Robles formulated such a problem in terms of the Kato-Nakayama-Usui completion of the period image and a conjectural Proj description involving the augmented Hodge line bundle and the boundary divisor on a smooth compactification of the base. We show that the essential obstruction to this description is divisor-theoretic: it may be expressed as a Picard-generation statement on the completed mixed period image. We prove this statement when the pure period image is one-dimensional, and consequently obtain the Deng-Robles Proj description in this case.
title Picard groups of completed period images and the Deng-Robles problem
topic Algebraic Geometry
14D07, 32G20, 14C20
url https://arxiv.org/abs/2603.09709