Appears in collection : Conference on Arithmetic Geometry in honor of Luc Illusie

Rapoport and Zink introduce the p-adic period domain (also called the admissible locus) inside the rigid analytic p-adic flag varieties. The weakly admissible locus is an approximation of the admissible locus in the sense that these two spaces have the same classical points. In this talk, we will try to describe the relation between the weakly admissible locus and the Newton stratification in the flag variety. This is a joint work in progress with Jilong Tong.