Immeubles de Kac–Moody hyperboliques, groupes non isomorphes de même immeuble (Hyperbolic Kac–Moody Buildings Nonisomorphic Groups with the Same Building)

Abstract

We first remark that Kac–Moody groups enable us to produce hyperbolic buildings – automatically endowed with nonuniform lattices. The main result then deals with groups whose buildings are trees or two-dimensional hyperbolic. It is a factorization theorem for abstract isomorphisms. It shows the existence of nonisomorphic Kac–Moody groups with the same associated isomorphism class of buildings.