  In Speakman and Lee (2017), we analytically developed the idea of using
volume as a measure for comparing relaxations in the context of spatial
branch-and-bound. Specifically, for trilinear monomials, we analytically
compared the three possible "double-McCormick relaxations" with the tight
convex-hull relaxation. Here, again using volume as a measure, for the
convex-hull relaxation of trilinear monomials, we establish simple rules for
determining the optimal branching variable and optimal branching point.
Additionally, we compare our results with current software practice.
