  We relate the relativistic finite range mean-field model (RMF-FR) to the
point-coupling variant and compare the nonlinear density dependence. From this,
the effective Hamiltonian of the nonlinear point-coupling model in the
nonrelativistic limit is derived. Different from the nonrelativistic models,
the nonlinearity in the relativistic models automatically yields contributions
in the form of a weak density dependence not only in the central potential but
also in the spin-orbit potential. The central potential affects the bulk and
surface properties while the spin-orbit potential is crucial for the shell
structure of finite nuclei. A modification in the Skyrme-Hartree-Fock model
with a density-dependent spin-orbit potential inspired by the point-coupling
model is suggested.
