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Bibliographic Details
Main Author: Yun, Ze
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2507.01731
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author Yun, Ze
author_facet Yun, Ze
contents We give degree lower bounds for quotient line bundles of the lowest piece of a Hodge module induced by a complex variation of Hodge structures outside a simple normal crossing divisor, beyond the unipotent variation case. This note aims to explain the failure of nefness when the monodromies at infinity are not unipotent. The lower bounds depend on local monodromies at infinity and intersection numbers with the boundary divisors. In particular it recovers Kawamata's semi-positivity theorem for unipotent variations. The proof is algebraic via a vanishing theorem for twisted Hodge modules. We also give geometric examples to show that the lower bound can be achieved.
format Preprint
id arxiv_https___arxiv_org_abs_2507_01731
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle On nefness of the lowest piece of Hodge modules
Yun, Ze
Algebraic Geometry
We give degree lower bounds for quotient line bundles of the lowest piece of a Hodge module induced by a complex variation of Hodge structures outside a simple normal crossing divisor, beyond the unipotent variation case. This note aims to explain the failure of nefness when the monodromies at infinity are not unipotent. The lower bounds depend on local monodromies at infinity and intersection numbers with the boundary divisors. In particular it recovers Kawamata's semi-positivity theorem for unipotent variations. The proof is algebraic via a vanishing theorem for twisted Hodge modules. We also give geometric examples to show that the lower bound can be achieved.
title On nefness of the lowest piece of Hodge modules
topic Algebraic Geometry
url https://arxiv.org/abs/2507.01731