The definition of set-comparator and bag-comparator specifically
mentions the lack of ordering of sets and bags:

 > The following comparators are used to compare sets or bags, and allow
sets of sets, bags of sets, etc.
 >
 > set-comparator
 >
 > bag-comparator
 >
 > Note that these comparators do not provide comparison procedures, as
there is no ordering between sets or bags. It is an error to compare
sets or bags with different element comparators.

Is there a reason for this specific restriction against comparisons? If
an implementation of SRFI-113 requires elements to be ordered, then it
can't implement these comparators in a way to create sets of sets and
other combinations.

-- Peter McGoron