Hodge Theory of Abelian Covers

Fuente: arXiv
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Hauptverfasser: Elduque, Eva, Cueto, Moisés Herradón
Format: Preprint
Veröffentlicht: 2023
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author Elduque, Eva
Cueto, Moisés Herradón
author_facet Elduque, Eva
Cueto, Moisés Herradón
contents Motivated by classical Alexander invariants of affine hypersurface complements, we endow certain finite dimensional quotients of the homology of abelian covers of complex algebraic varieties with a canonical and functorial mixed Hodge structure (MHS). More precisely, we focus on covers which arise algebraically in the following way: if $U$ is a smooth connected complex algebraic variety and $G$ is a complex semiabelian variety, the pullback of the exponential map by an algebraic morphism $f:U\to G$ yields a covering space $π:U^f\to U$ whose group of deck transformations is $π_1(G)$. The new MHSs are compatible with Deligne's MHS on the homology of $U$ through the covering map $π$ and satisfy a direct sum decomposition as MHSs into generalized eigenspaces by the action of deck transformations. This provides a vast generalization of the previous results regarding univariable Alexander modules by Geske, Maxim, Wang and the authors. Lastly, we reduce the problem of whether the first Betti number of the Milnor fiber of a central hyperplane arrangement complement is combinatorial to a question about the Hodge filtration of certain MHSs defined in this paper, providing evidence that the new structures contain interesting information.
format Preprint
id arxiv_https___arxiv_org_abs_2401_00489
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Hodge Theory of Abelian Covers
Elduque, Eva
Cueto, Moisés Herradón
Algebraic Geometry
Algebraic Topology
14C30, 14D07, 14F40, 14F45, 32S22, 32S35, 32S40, 32S50, 32S55, 55N25, 55N30
Motivated by classical Alexander invariants of affine hypersurface complements, we endow certain finite dimensional quotients of the homology of abelian covers of complex algebraic varieties with a canonical and functorial mixed Hodge structure (MHS). More precisely, we focus on covers which arise algebraically in the following way: if $U$ is a smooth connected complex algebraic variety and $G$ is a complex semiabelian variety, the pullback of the exponential map by an algebraic morphism $f:U\to G$ yields a covering space $π:U^f\to U$ whose group of deck transformations is $π_1(G)$. The new MHSs are compatible with Deligne's MHS on the homology of $U$ through the covering map $π$ and satisfy a direct sum decomposition as MHSs into generalized eigenspaces by the action of deck transformations. This provides a vast generalization of the previous results regarding univariable Alexander modules by Geske, Maxim, Wang and the authors. Lastly, we reduce the problem of whether the first Betti number of the Milnor fiber of a central hyperplane arrangement complement is combinatorial to a question about the Hodge filtration of certain MHSs defined in this paper, providing evidence that the new structures contain interesting information.
title Hodge Theory of Abelian Covers
topic Algebraic Geometry
Algebraic Topology
14C30, 14D07, 14F40, 14F45, 32S22, 32S35, 32S40, 32S50, 32S55, 55N25, 55N30
url https://arxiv.org/abs/2401.00489