English

Linear Chern-Hopf-Thurston conjecture

Algebraic Geometry 2024-09-30 v3 Differential Geometry Geometric Topology

Abstract

If XX is a closed 2n2n-dimensional aspherical manifold, i.e., the universal cover of XX is contractible, then the Chern-Hopf-Thurston conjecture predicts that (1)nχ(X)0(-1)^n\chi(X)\geq 0. We prove this conjecture when XX 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 XX is a complex projective manifold with large fundamental group and π1(X)\pi_1(X) admits an almost faithful linear representation, then χ(X,P)0\chi(X, \mathcal{P})\geq 0 for any perverse sheaf P\mathcal{P} on XX. 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.

Keywords

Cite

@article{arxiv.2405.12012,
  title  = {Linear Chern-Hopf-Thurston conjecture},
  author = {Ya Deng and Botong Wang},
  journal= {arXiv preprint arXiv:2405.12012},
  year   = {2024}
}
R2 v1 2026-06-28T16:33:04.557Z