Minimal -crystals and isomorphism numbers of isosimple -crystals
arXiv:1509.01192
Abstract
In this paper we generalize minimal -divisible groups defined by Oort to -crystal over an algebraically closed field of positive characteristic. We prove a structural theorem and give an explicit formula of the Frobenius endomorphism of the isosimple minimal -crystals that are the building blocks of minimal -crystals. We then define an invariant called the minimal height for -crystals using minimal -crystals and give an upper bound of the isomorphism numbers of isosimple -crystals in terms of their ranks, Hodge slopes and Newton slopes.
Final accepted version at Math. Nachr