#### Abstract

Let k be a perfect field of characteristic p > 0. Let X, Y be isoclinic Barsotti-Tate groups with Frobenius slopes μX , μY respectively, with μX < μY . The “extension part” DE(X,Y ) of the equi-characteristic deformation space Def(X,Y ) of X × Y has a natural structure as a commutate smooth formal group over k. We show that the central leaf in the… (More)