6 papers
Torsors on the complement of a smooth divisor
Kestutis Cesnavicius
We complete the proof of the Nisnevich conjecture in equal characteristic: for a smooth algebraic variety over a field , a -smooth divisor , and a reductive…
Unramified Grothendieck-Serre for isotropic groups
Kestutis Cesnavicius, Roman Fedorov
The Grothendieck-Serre conjecture predicts that every generically trivial torsor under a reductive group over a regular semilocal ring is trivial. We establish this for unr…
The affine Grassmannian as a presheaf quotient
Kestutis Cesnavicius
For a reductive group over a ring , its affine Grassmannian plays important roles in a wide range of subjects and is typically defined as the étale sheafifi…
Problems about torsors over regular rings (with an appendix by Yifei Zhao)
Kestutis Cesnavicius
We overview a web of conjectures about torsors under reductive groups over regular rings and survey some techniques that have been used for making progress on such problems.
Generically trivial torsors under constant groups
Alexis Bouthier, Kestutis Cesnavicius, Federico Scavia
We resolve the Grothendieck-Serre question over an arbitrary base field : for a smooth -group scheme and a smooth -variety , we show that every generically trivial…
The analytic topology suffices for the -Grassmannian
Kestutis Cesnavicius, Alex Youcis
The -affine Grassmannian was introduced by Scholze in the context of the geometric local Langlands program in mixed characteristic and is the Fargues-Fontaine cu…