  We treat short-range correlations in nuclear matter, induced by the repulsive
core of the nucleon-nucleon potential, within the framework of a
self-consistent Green's function theory. The effective in-medium interaction
sums the ladder diagrams of both the particle-particle and hole-hole type. The
demand of self-consistency results in a set of nonlinear equations which must
be solved by iteration. We explore the possibility of approximating the
single-particle Green's function by a limited number of poles and residues.
