Perverse $\mathbb{F}_p$-sheaves on the affine Grassmannian

Autor: Cass, Robert
Rok vydání: 2019
Předmět:
Zdroj: J. Reine Angew. Math. 785 (2022), 219-272
Druh dokumentu: Working Paper
Popis: For a reductive group over an algebraically closed field of characteristic $p > 0$ we construct the abelian category of perverse $\mathbb{F}_p$-sheaves on the affine Grassmannian that are equivariant with respect to the action of the positive loop group. We show this is a symmetric monoidal category, and then we apply a Tannakian formalism to show this category is equivalent to the category of representations of a certain affine monoid scheme. We also show that our work provides a geometrization of the inverse of the mod $p$ Satake isomorphism. Along the way we prove that affine Schubert varieties are globally $F$-regular and we apply Frobenius splitting techniques to the theory of perverse $\mathbb{F}_p$-sheaves.
Comment: Final version
Databáze: arXiv