  Ab-initio correlation results for an idealized high Tc-compound are compared
to density functional (DF) calculations for the same system. It is shown that
and why the DF-charge distribution is wrong. The largest deficiency arises for
the Cu-d(x2-y2)-occupation, originating from strong atomic correlations but
mostly from anomalous neighbor Cu-spin correlations. Both features are beyound
the range of the homogeneous electron gas approximation underlying the
DF-schemes. The ab-initio results also exclude a description of the real system
in a Mott-Hubbard scenario, that is mostly chosen in theory.
