- distribute_constr(+X, +Rgn) is det
- Distribute a region constraint Rgn down to the leaves of X.
- region_constr_of_leaves(+X, +Rgn, +P, -Q) is det
- The list of region constraints on leaves of X with Rgn
propagated down is a difference list P by Q.
- unify(+X, +Y) is det
- unify X with Y.
- close_btree(+X) is det
- Close all leaves of X with  (void tree)
The following predicates are exported, but not or incorrectly documented.
- find_key(Arg1, Arg2, Arg3)