2004/12/20 by Lars Brünjes, Brünjes, Lars, Christian Serpé +1 · 2 citations
Mathematics · #03H05 #14F20 #Advanced Topology and Set Theory #Algebraic Geometry (math.AG) #FOS: Mathematics #History and Theory of Mathematics #Logic (math.LO) #Mathematical and Theoretical Analysis #math.AG #math.LO #msc:03H05 #msc:14F20
paper · pdf · doi:10.48550/arxiv.math/0412406
arxiv created 2004/12/20 · openalex publication_date 2004/12/20 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
A lot of good properties of etale cohomology only hold for torsion coefficients. We use "enlargement of categories" as developed in http://arxiv.org/abs/math.CT/0408177 to define a cohomology theory that inherits the important properties of etale cohomology while allowing greater flexibility with the coefficients. In particular, choosing coefficients *Z/P (for P an infinite prime and *Z the enlargement of Z) gives a Weil cohomology, and choosing *Z/lh (for l a finite prime and h an infinite number) allows comparison with ordinary l-adic cohomology. More generally, for every N in *Z, we get a category of *Z/N-constructible sheaves with good properties.