Nonabelian basechange theorems and étale homotopy theory

This paper has two main goals. First, we prove nonabelian refinements of basechange theorems in étale cohomology (i.e., prove analogues of the classical statements for sheaves of spaces). Second, we apply these theorems to prove a number of results about the étale homotopy type. Specifically, we p...

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Hauptverfasser: Haine, Peter (VerfasserIn) , Holzschuh, Tim (VerfasserIn) , Wolf, Sebastian (VerfasserIn)
Dokumenttyp: Article (Journal)
Sprache:Englisch
Veröffentlicht: December 2024
In: Journal of topology
Year: 2024, Jahrgang: 17, Heft: 4, Pages: 1-45
ISSN:1753-8424
DOI:10.1112/topo.70009
Online-Zugang:Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1112/topo.70009
Verlag, lizenzpflichtig, Volltext: https://onlinelibrary.wiley.com/doi/abs/10.1112/topo.70009
Volltext
Verfasserangaben:Peter J. Haine, Tim Holzschuh, Sebastian Wolf
Beschreibung
Zusammenfassung:This paper has two main goals. First, we prove nonabelian refinements of basechange theorems in étale cohomology (i.e., prove analogues of the classical statements for sheaves of spaces). Second, we apply these theorems to prove a number of results about the étale homotopy type. Specifically, we prove nonabelian refinements of the smooth basechange theorem, Huber-Gabber affine analogue of the proper basechange theorem, and Fujiwara-Gabber rigidity theorem. Our methods also recover Chough's nonabelian refinement of the proper basechange theorem. Transporting an argument of Bhatt-Mathew to the nonabelian setting, we apply nonabelian proper basechange to show that the profinite étale homotopy type satisfies arc-descent. Using nonabelian smooth and proper basechange and descent, we give rather soft proofs of a number of Künneth formulas for the étale homotopy type.
Beschreibung:Gesehen am 16.06.2025
Beschreibung:Online Resource
ISSN:1753-8424
DOI:10.1112/topo.70009