Matilde Maccan "Homogeneous spaces in characteristic 2 and 3"
Channel: Schubert Seminar
Date: 2022-12-12

Abstract: Our aim is to classify projective algebraic varieties (over an algebraically closed field) which are homogeneous under a semisimple algebraic group G : this translates into the study of their stabilizers, called parabolic subgroups. Over C, their description is known and combinatorial, while in positive characteristic p it is more complicated, due to the fact that algebraic groups are not necessarily reduced. We first introduce some notation and examples, then state and (partly) generalize a result of Wenzel - classifying all parabolic subgroups when p \geq 5 in terms of roots and Frobenius kernels - to a base field of characteristic 2 or 3.