  Modern softened nucleon-nucleon interactions are well-suited for perturbative
many-body calculations, but a many-body power counting scheme is lacking.
Estimates of diagrammatic contributions at finite density are important
ingredients in such a scheme. Here we show how to make quantitative estimates
of the particle-particle and hole-hole channel in uniform nuclear matter for
soft interactions. We also use estimates to assess the role of normal-ordered
three-body forces for a pure contact interaction.
