On specializations of minimal -divisible groups
arXiv:1705.10042
Abstract
In this paper, for any pair of Newton polygons with , we construct a concrete specialization from the minimal -divisible group of to the minimal -divisible group of by a beautiful induction. This in particular gives the affirmative answer to the unpolarized analogue of a question by Oort on the boundaries of central streams, and gives another proof of the dimension formula of the central leaves in the unpolarized case.