Newton polygons and p-divisible groups : a conjecture by Grothendieck

Abstract

Talk on 27-IV-2000 in the 'automorphic semester' Centre Emile Borel at Institut Henri Poincare We consider p-divisible groups (also called Barsotti-Tate groups) in characteristic p, abelian varieties, their deformations, and we draw some conclusions. For a p-divisible group (in characteristic p) we can define its Newton polygon. This is invariant under isogeny. For an abelian variety the Newton polygon of its p-divisible group is "symmetric". We are interested in the strata defined by Newton polygons in local deformation spaces, or in the moduli space of polarized abelian...