“…Thus dim(P ) is the least positive integer d such that P has a realizer of size d. Accordingly, to establish an upper bound of the form dim(P ) d, the most natural approach is simply to construct a realizer of size d for P . However, in recent papers [8,9,12,13,14,15,16,21,23,28,30], another approach has been taken. Let Inc(P ) denote the set of ordered incomparable pairs of P .…”