  The role of three-nucleon forces (3NF) in the description of nuclear
structure properties is nowadays a main topic in the field of microscopic
many-nucleon calculations. We investigate the relative weight between effective
two- and three-nucleon forces in neutron-rich nuclei beyond the doubly-closed
132Sn core within the realistic shell-model framework, studying the evolution
of the spectroscopic properties of N=82 isotopes and heavy tin isotopes. This
problem is tackled indirectly without explicitly taking into account effective
3NF through the comparison of the results of shell-model calculations obtained
from realistic on-shell-equivalent low-momentum potentials.
