Lifting endomorphisms of formal Ο_K-modules

We present Keating's results on lifts of endomorphisms of formal Ο_K-modules over a power series ring. Let k be a separably closed field of characteristic p. Let K a complete discretely valued field of characteristic p with finite residue field and Ο_K its ring of integers. Let F be a formal Ο_K-module over k[[t]] with generic fiber of height h - 1 and special fiber of height h. We compute the endomorphism ring of the reduction of F to k[[t]]/(tⁿ⁺¹).