Let be a -divisible group with constant Newton polygon over a normal Noetherian scheme . We prove that there exists an isogeny such that admits a slope filtration. In case is regular this was proved by N. Katz for dim and by T. Zink for dim .
Cite this article
Frans Oort, Thomas Zink, Families of -divisible groups with constant Newton polygon. Doc. Math. 7 (2002), pp. 183–201DOI 10.4171/DM/123