11 papers · 1 filter
Categorical Künneth formulas for cohomological motives
Timo Richarz, Jakob Scholbach
The manuscript at hand systematically studies Künneth formulas at a categorical level. We give criteria for an abstract six functor formalism to satisfy the categorical Künneth for…
Frobenius rigidity in -homotopy theory
Timo Richarz, Jakob Scholbach
We study the homotopy fixed points under the Frobenius endomorphism on the stable -homotopy category of schemes in characteristic and prove a rigidity result for…
Normality of Schubert varieties in affine Grassmannians
Patrick Bieker, Timo Richarz
We classify all normal Schubert varieties in the affine Grassmannian of a semisimple group over an arbitrary field with special attention to small positive characteristic. The proo…
Constructible sheaves on schemes
Tamir Hemo, Timo Richarz, Jakob Scholbach
We present a uniform theory of constructible sheaves on arbitrary schemes with coefficients in topological or even condensed rings. This is accomplished by defining lisse sheaves t…
Néron blowups and low-degree cohomological applications
Arnaud Mayeux, Timo Richarz, Matthieu Romagny
We define dilatations of general schemes and study their basic properties. Dilatations of group schemes are -- in favorable cases -- again group schemes, called Néron blowups. We g…
Normality and Cohen-Macaulayness of parahoric local models
Thomas J. Haines, Timo Richarz
We study the singularities of integral models of Shimura varieties and moduli stacks of shtukas with parahoric level structure. More generally our results apply to the Pappas-Zhu a…