Linear Chern-Hopf-Thurston conjecture

Fuente: arXiv
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Main Authors: Deng, Ya, Wang, Botong
Format: Preprint
Published: 2024
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author Deng, Ya
Wang, Botong
author_facet Deng, Ya
Wang, Botong
contents If $X$ is a closed $2n$-dimensional aspherical manifold, i.e., the universal cover of $X$ is contractible, then the Chern-Hopf-Thurston conjecture predicts that $(-1)^nχ(X)\geq 0$. We prove this conjecture when $X$ is a complex projective manifold whose fundamental group admits an almost faithful linear representation over any field. In fact, we prove a much stronger statement that if $X$ is a complex projective manifold with large fundamental group and $π_1(X)$ admits an almost faithful linear representation, then $χ(X, \mathcal{P})\geq 0$ for any perverse sheaf $\mathcal{P}$ on $X$. To prove this, we introduce a vanishing cycle functor of multivalued one-forms and apply techniques from non-abelian Hodge theory, both in archimedean and non-archimedean settings. These techniques allow us to deduce the desired positivity from the geometric properties of pure and mixed period maps.
format Preprint
id arxiv_https___arxiv_org_abs_2405_12012
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Linear Chern-Hopf-Thurston conjecture
Deng, Ya
Wang, Botong
Algebraic Geometry
Differential Geometry
Geometric Topology
If $X$ is a closed $2n$-dimensional aspherical manifold, i.e., the universal cover of $X$ is contractible, then the Chern-Hopf-Thurston conjecture predicts that $(-1)^nχ(X)\geq 0$. We prove this conjecture when $X$ is a complex projective manifold whose fundamental group admits an almost faithful linear representation over any field. In fact, we prove a much stronger statement that if $X$ is a complex projective manifold with large fundamental group and $π_1(X)$ admits an almost faithful linear representation, then $χ(X, \mathcal{P})\geq 0$ for any perverse sheaf $\mathcal{P}$ on $X$. To prove this, we introduce a vanishing cycle functor of multivalued one-forms and apply techniques from non-abelian Hodge theory, both in archimedean and non-archimedean settings. These techniques allow us to deduce the desired positivity from the geometric properties of pure and mixed period maps.
title Linear Chern-Hopf-Thurston conjecture
topic Algebraic Geometry
Differential Geometry
Geometric Topology
url https://arxiv.org/abs/2405.12012