English

Gersten-type conjecture for henselian local rings of normal crossing varieties

Algebraic Geometry 2026-03-06 v4 Number Theory

Abstract

Let n0n\geq 0 and r>0r>0 be integers. Let OX,xh\mathcal{O}_{X, x}^{h} be the henselization of the local ring OX,x\mathcal{O}_{X, x} of a scheme XX at a point xXx\in X. For a normal crossing variety YY over the spectrum of a field kk of positive characteristic p>0p>0, K..Sato defined an \'{e}tale logarithmic Hodge-Witt sheaf λY,rn\lambda^{n}_{Y, r} on the \'{e}tale site YeˊtY_{\mathrm{\acute{e}t}} which agrees with WrΩY,lognW_{r}\Omega^{n}_{Y, \log} in the case where YY is smooth over Spec(k)\operatorname{Spec}(k). In this paper, we prove the Gersten-type conjecture for \'{e}tale sheaves which satisfy some properties over OY,yh\mathcal{O}_{Y, y}^{h}. For example, λY,rn\lambda_{Y, r}^{n} and μln\mu_{l}^{\otimes n} satisfy these properties where μl\mu_{l} is the \'{e}tale sheaf of ll-th roots of unity for an integer ll which is prime to the characteristic of YY. Let BB be a discrete valuation ring of mixed characteristic (0,p)(0, p) and X\mathfrak{X} a semistable family over Spec(B)\operatorname{Spec}(B). Suppose that BB contains pp-th roots of unity. As an application of the Gersten-type conjecture for λrn\lambda^{n}_{r}, we prove the relative version of the Gersten-type conjecture for the pp-adic \'{e}tale Tate twist T1(n)\mathfrak{T}_{1}(n) over OX,xh\mathcal{O}_{\mathfrak{X}, x}^{h}. Moreover, we prove a generalization of Artin's theorem about the Brauer groups.

Keywords

Cite

@article{arxiv.2402.18042,
  title  = {Gersten-type conjecture for henselian local rings of normal crossing varieties},
  author = {Makoto Sakagaito},
  journal= {arXiv preprint arXiv:2402.18042},
  year   = {2026}
}

Comments

75 pages, Abstract changed