SRFI 113 defines set-comparator and bag-comparator. It says that they can be used for sets of sets, bags of sets, etc.

Then it says that these comparators do not provide comparison procedures. 

However, an implementation of bags and sets may need the comparison procedures; SRFI 113 says in this regard: Comparators conveniently package the equality predicate of the set with the hash function or comparison procedure needed to implement the set efficiently.

All three things together do not make sense.

One way to cure the defect could be to demand that set-comparator and bag-comparator provide comparison procedures at least when the implementation of sets and bags is based on the comparison function of its elements (and not only on the equality predicate and the hash function).

Marc