The closed interval between $p$ and $q$ is the subposet of $P$ induced by the elements $z$ such that $p \leq z \leq q$. If $p$ and $q$ are incomparable, then an error is thrown.
i1 : P = booleanLattice 3; |
i2 : closedInterval(P, "001", "111") o2 = Relation Matrix: | 1 1 1 1 | | 0 1 0 1 | | 0 0 1 1 | | 0 0 0 1 | o2 : Poset |
The object closedInterval is a method function.