English

Divisibility phenomena in motivic Bloch--Ogus theory

Algebraic Geometry 2026-05-22 v1 K-Theory and Homology

Abstract

Let X be a smooth projective variety over a field k. For k separably closed, we prove that the subgroup of unramified classes in the Milnor K-group KiM(k(X))K^M_i(k(X)) of the function field of X is contained in the subgroup of n-divisible elements of KiM(k(X))K^M_i(k(X)) for any integer n invertible in k. This generalizes to a statement for unramified motivic cohomology of arbitrary bidegree. We further show that whenever k is finite or separably closed and l is a prime invertible in k, then all but the last step in the Bloch--Ogus filtration of the motivic cohomology of X are l-divisible up to torsion. Generalizations of this last result to arbitrary quasi-projective k-schemes are also proven.

Keywords

Cite

@article{arxiv.2605.22494,
  title  = {Divisibility phenomena in motivic Bloch--Ogus theory},
  author = {Jean-Louis Colliot-Thélène and Stefan Schreieder},
  journal= {arXiv preprint arXiv:2605.22494},
  year   = {2026}
}

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40 pages