  We demonstrate that by considering disordered single-particle Hamiltonians
(or their random matrix versions) on ultrametric spaces one can generate an
interesting class of models exhibiting Anderson metal-insulator transition. We
use the weak disorder virial expansion to determine the critical value of the
parameters and to calculate the values of the multifractal exponents for
inverse participation ratios. Direct numerical simulations agree favourably
with the analytical predictions.
