Non-equivalences of motivic codimension filtration quotients

Fuente: arXiv
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Main Authors: Druzhinin, A. E., Urazbaev, A. A.
Format: Preprint
Published: 2024
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author Druzhinin, A. E.
Urazbaev, A. A.
author_facet Druzhinin, A. E.
Urazbaev, A. A.
contents We prove that a motivic equivalence of objects of the form \begin{equation*} X/(X-x)\simeq X^\prime/(X^\prime-x^\prime) \end{equation*} in $\mathbf{H}^\bullet(B)$ or $\mathbf{DM}(B)$ over a scheme $B$, where $x$ and $x^\prime$ are closed points of smooth $B$-schemes $X$ and $X^\prime$, implies an isomorphism of residue fields, i.e. \[x\cong x^\prime.\] For a given $d\geq 0$, $X,X^\prime\in\mathrm{Sm}_B$, $\operatorname{dim}_B X=d=\operatorname{dim}_B X^\prime$, and closed points $x$ and $x^\prime$ that residue fields are simple extensions of the ones of $B$, we show an isomorphism of groups \[\mathrm{Hom}_{\mathbf{DM}(B)}(X/(X-x),X^\prime/(X^\prime-x^\prime)))\cong\mathrm{Cor}(x,x^\prime),\] and prove that it leads to an equivalence of subcategories. Additionally, using the result on perverse homotopy heart by F.~Déglise and N.~Feld and F.~Jin and the strict homotopy invariance theorem for presheaves with transfers over fields by the first author, we prove an equivalence of the Rost cycle modules category and the homotopy heart of $\mathbf{DM}(k)$ over a field $k$ with integral coefficients.
format Preprint
id arxiv_https___arxiv_org_abs_2410_03636
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Non-equivalences of motivic codimension filtration quotients
Druzhinin, A. E.
Urazbaev, A. A.
Algebraic Geometry
K-Theory and Homology
14F35, 14F42, 19E15, 55P99
We prove that a motivic equivalence of objects of the form \begin{equation*} X/(X-x)\simeq X^\prime/(X^\prime-x^\prime) \end{equation*} in $\mathbf{H}^\bullet(B)$ or $\mathbf{DM}(B)$ over a scheme $B$, where $x$ and $x^\prime$ are closed points of smooth $B$-schemes $X$ and $X^\prime$, implies an isomorphism of residue fields, i.e. \[x\cong x^\prime.\] For a given $d\geq 0$, $X,X^\prime\in\mathrm{Sm}_B$, $\operatorname{dim}_B X=d=\operatorname{dim}_B X^\prime$, and closed points $x$ and $x^\prime$ that residue fields are simple extensions of the ones of $B$, we show an isomorphism of groups \[\mathrm{Hom}_{\mathbf{DM}(B)}(X/(X-x),X^\prime/(X^\prime-x^\prime)))\cong\mathrm{Cor}(x,x^\prime),\] and prove that it leads to an equivalence of subcategories. Additionally, using the result on perverse homotopy heart by F.~Déglise and N.~Feld and F.~Jin and the strict homotopy invariance theorem for presheaves with transfers over fields by the first author, we prove an equivalence of the Rost cycle modules category and the homotopy heart of $\mathbf{DM}(k)$ over a field $k$ with integral coefficients.
title Non-equivalences of motivic codimension filtration quotients
topic Algebraic Geometry
K-Theory and Homology
14F35, 14F42, 19E15, 55P99
url https://arxiv.org/abs/2410.03636