Serre-Tate theory for Shimura varieties of Hodge type
arXiv:1612.06456
Abstract
We study the formal neighbourhood of a point in -ordinary locus of an integral model of a Hodge type Shimura variety. We show that this formal neighbourhood has a structure of a shifted cascade. Moreover we show that the CM points on the formal neighbourhood are dense and that the identity section of the shifted cascade corresponds to a lift of the abelian variety which has a characterization in terms of its endomorphisms in analogy with the Serre-Tate canonical lift of an ordinary abelian variety.
Some more details added. Appendix moved to main body of text as section 5