  A many-body wave function can be factorized in Fock space into a marginal
amplitude describing a set of strongly correlated orbitals and a conditional
amplitude for the remaining weakly correlated part. The marginal amplitude is
the solution of a Schr\"odinger equation with an effective Hamiltonian that can
be viewed as embedding the marginal wave function in the environment of weakly
correlated electrons. Here, the complementary equation for the conditional
amplitude is replaced by a generalized Kohn-Sham equation, for which an
orbital-dependent functional approximation is shown to reproduce the
topological phase diagram of a multiband Hubbard model as a function of crystal
field and Hubbard parameters. The roles of band filling and interband
fluctuations are elucidated.
