Comparison of motives with rational coefficients

Fuente: arXiv
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Auteur principal: Zhang, Bo
Format: Preprint
Publié: 2025
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_version_ 1866912781542883328
author Zhang, Bo
author_facet Zhang, Bo
contents The theory of rational motives admits several models, including those of Morel, Beilinson, Ayoub, and Voevodsky. An open question has been the equivalence of Voevodsky's Nisnevich-based $\mathrm{DM}(S, \mathbb{Q})$ with the others, which was only known over excellent and geometrically unibranch base schemes. In this paper, we prove that $\mathrm{DM}(S, \mathbb{Q})$ is equivalent to Morel/Beilinson/Ayoub's rational motives over any quasi-excellent base scheme $S$. Our main technical result is a stable motivic equivalence between the plus part of free $\mathbb{Q}$-linear spectrum $\mathbb{Q}[\mathbb{S}]$ and the motivic rational Eilenberg MacLane spectrum $\mathbf{H}\mathbb{Q}$. This equivalence is established whenever Ayoub's motives $\mathrm{DA}(S, \mathbb{Q})$ satisfies h-descent. As a byproduct, we partially confirm Voevodsky's conjecture that the formation of motivic rational Eilenberg Maclane spectrum $\mathbf{H}\mathbb{Q}$ is stable under base change between any quasi-excellent scheme.
format Preprint
id arxiv_https___arxiv_org_abs_2510_17194
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Comparison of motives with rational coefficients
Zhang, Bo
Algebraic Geometry
Algebraic Topology
The theory of rational motives admits several models, including those of Morel, Beilinson, Ayoub, and Voevodsky. An open question has been the equivalence of Voevodsky's Nisnevich-based $\mathrm{DM}(S, \mathbb{Q})$ with the others, which was only known over excellent and geometrically unibranch base schemes. In this paper, we prove that $\mathrm{DM}(S, \mathbb{Q})$ is equivalent to Morel/Beilinson/Ayoub's rational motives over any quasi-excellent base scheme $S$. Our main technical result is a stable motivic equivalence between the plus part of free $\mathbb{Q}$-linear spectrum $\mathbb{Q}[\mathbb{S}]$ and the motivic rational Eilenberg MacLane spectrum $\mathbf{H}\mathbb{Q}$. This equivalence is established whenever Ayoub's motives $\mathrm{DA}(S, \mathbb{Q})$ satisfies h-descent. As a byproduct, we partially confirm Voevodsky's conjecture that the formation of motivic rational Eilenberg Maclane spectrum $\mathbf{H}\mathbb{Q}$ is stable under base change between any quasi-excellent scheme.
title Comparison of motives with rational coefficients
topic Algebraic Geometry
Algebraic Topology
url https://arxiv.org/abs/2510.17194