On reduction of Hilbert-Blumenthal varieties
Let be the ring of integers of a totally real field of degree . We study the reduction of the moduli space of separably polarized abelian -varieties of dimension modulo for a fixed prime . The invariants and related conditions for the objects in the moduli space are discussed. We construct a scheme-theoretic stratification by -types on the Rapoport locus and study the relation with the slope stratification. In particular, we recover the main results of Goren and Oort [J. Alg. Geom.,...