  Linear response functions are calculated for symmetric nuclear matter of
normal density by time-evolving two-time Green's functions with conserving
self-energy insertions, thereby satisfying the energy-sum rule. Nucleons are
regarded as moving in a mean field defined by an effective mass. A two-body
effective (or residual) interaction, represented by a gaussian local
interaction, is used to find the effect of correlations in a second order as
well as a ring approximation. The response function S(e,q) is calculated for
0.2<q<1.2 fm^{-1}. Comparison is made with the nucleons being un-correlated,
"RPA+HF" only.
