  In this article, we combine the ideas introduced by us earlier in various
proportions to arrive at a simple and yet powerful means of studying
single-particle properties of homogeneous Fermi systems in detail without
making assumptions regarding the validity or otherwise of Fermi-liquid theory.
Novelties include the exact forms of the momentum distribution and spectral
functions in the intermediate density regime and a dielectric function that is
sensitive to significant qualitative changes in single-particle properties.
This time, care is taken to include the particle-hole mode by interpreting the
sum over modes as a weighted sum with the dynamical structure factor appearing
as the weight.
