  An exact treatment of the operators Q/e(\omega) and the total momentum is
adopted to solve the nuclear matter Bruecker-Bethe-Goldstone equation with two-
and three-body forces. The single-particle potential, equation of state and
nucleon effective mass are calculated from the exact G-matrix. The results are
compared with those obtained under the angle-average approximation and the
angle-average approximation with total momentum approximation. It is found that
the angle-average procedure, whereas preventing huge calculations of coupled
channels, nevertheless provides a fairly accurate approximation. On the
contrary, the total momentum approximation turns out to be quite inaccurate
compared to its exact counterpart.
