A better comparison of cdh- and ldh-cohomologies
Abstract
In order to work with non-Nagata rings which are Nagata "up-to-completely-decomposed-universal-homeomorphism", specifically finite rank hensel valuation rings, we introduce the notions of pseudo-integral closure and pseudo-normalisation. We use this notion to give a much more direct and shorter proof that for homotopy sheaves of modules over the -linear motivic Eilenberg-Maclane spectrum. This comparison is an alternative to the first half of the authors volume Ast\'erisque 391, whose main theorem is a cdh-descent result for Voevodsky motives. The motivating new insight is really accepting that Voevodsky's motivic cohomology (with -coefficients) is invariant not just for nilpotent thickenings, but for all universal homeomorphisms.
Keywords
Cite
@article{arxiv.1807.00158,
title = {A better comparison of cdh- and ldh-cohomologies},
author = {Shane Kelly},
journal= {arXiv preprint arXiv:1807.00158},
year = {2020}
}
Comments
Main theorem hypothesis (G1) or (G2) changed to (G1) *and* (G2). Proof remains essentially the same