English

Topological Hochschild homology and Zeta-values

Number Theory 2021-07-12 v2 Algebraic Geometry

Abstract

Using work of Antieau and Bhatt-Morrow-Scholze, we define a filtration on topological Hochschild homology and its variants TPTP and TCTC^- of quasi-lci rings with bounded torsion, which recovers the BMS-filtration after pp-adic completion. Then we compute the graded pieces of this filtration in terms of Hodge completed derived de Rham cohomology relative to the base ring Z\mathbb{Z}. We denote the cofiber of the canonical map from grnTC()\mathrm{gr}^{n}TC^-(-) to grnTP()\mathrm{gr}^{n}TP(-) by LΩ/S<n[2n]L\Omega^{<n}_{-/\mathbb{S}}[2n]. Let X\mathcal{X} be a regular connected scheme of dimension dd proper over Spec(Z)\mathrm{Spec}(\mathbb{Z}) and let nZn\in\mathbb{Z} be an arbitrary integer. Together with Weil-\'etale cohomology with compact support RΓW,c(X,Z(n))R\Gamma_{W,c}(\mathcal{X},\mathbb{Z}(n)), the complex LΩX/S<nL\Omega^{<n}_{\mathcal{X}/\mathbb{S}} is expected to give the Zeta-value ±ζ(X,n)\pm\zeta^*(\mathcal{X},n) on the nose. Combining the results proven here with a theorem recently proven in joint work with Flach, we obtain a formula relating LΩX/S<nL\Omega^{<n}_{\mathcal{X}/\mathbb{S}}, LΩX/S<dnL\Omega^{<d-n}_{\mathcal{X}/\mathbb{S}}, Weil-\'etale cohomology of the archimedean fiber X\mathcal{X}_{\infty} with Tate twists nn and dnd-n, the Bloch conductor A(X)A(\mathcal{X}) and the special values of the archimedean Euler factor of the Zeta-function ζ(X,s)\zeta(\mathcal{X},s) at s=ns=n and s=dns=d-n. This formula is a shadow of the functional equation of Zeta-functions.

Keywords

Cite

@article{arxiv.2011.11549,
  title  = {Topological Hochschild homology and Zeta-values},
  author = {Baptiste Morin},
  journal= {arXiv preprint arXiv:2011.11549},
  year   = {2021}
}