Seminar by Sian Nie: Steinberg’s cross-section of Newton strata



Time: 15:00-16:00, May 31


Venue: Lecture Hall


Abstract: Let G be a simply connected semisimple group of rank r over an algebraically closed field. Steinberg has associated to each minimal length Coxeter element an r-dimensional affine space in G, which is a cross-section of all regular conjugacy classes of G. In this talk, we will consider natural analogues of Steinberg’s cross-sections in the context of a loop group equipped with a Frobenius automorphism. We will show how Steinberg’s cross-sections intersect Frobenius twisted conjugacy classes (which are parameterized by Newton polygons). Some interesting applications will also be discussed.