2000 character limit reached
Normality of Schubert varieties in affine Grassmannians (2312.11154v1)
Published 18 Dec 2023 in math.AG and math.RT
Abstract: 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 proof is elementary and relies on tangent space calculations for quasi-minuscule Schubert varieties, a refined Levi lemma in positive characteristic and the classification of minimal degenerations