 Intuitively, this says that if an object fails to include another among its parts, then there must be a remainder, something that makes up for the difference. It is easily seen that, given M, (P.5) implies (P.4), so any M-theory violating (P.4) will a fortiori violate (P.5). For instance, on Whitehead's boundary-free theory of extensive connection, a closed region is not part of its interior even though each part of the former overlaps the latter. More generally, the entailment holds as long as parthood is antisymmetric (see again Figure 3, center, for a non-antisymmetric counterexample). However, the converse is not true. The diagram in Figure 4 illustrates an M-model in which (P.4) is satisfied, since each proper part counts as a supplement of the other; yet (P.5) is false.