Cristaux et immeubles
  Let G be a connected reductive group defined over Q_p. The set of crystals contained in a given G-isocrystal is viewed from a Bruhat-Tits building-theoretic vantage point as a kind of tubular neighborhood of a skeleton characterized by a minimality property arising from metric space theory. 
Christophe Cornut, Marc-Hubert Nicole
math.NT math.MG