Zeta functions of groups and enumeration in Bruhat-Tits buildings

We introduce a new method to calculate local normal zeta functions of finitely generated, torsion-free nilpotent groups, T-groups in short. It is based on an enumeration of vertices in the Bruhat-Tits building for Sln(Qp). It enables us to give explicit computations for T-groups of class 2 with small centres and to derive local functional equations. Examples include formulae for non-uniform normal zeta functions.