same fringe. For now, one straightforward way to determine this would be:
enumerate the fringe of the first tree. That gives you a list. Enumerate the
fringe of the second tree. That also gives you a list. Then compare the two
-lists to see if they're equal. (You just programmed this above.)
+lists to see if they're equal.
+
+Write the fringe-enumeration function. It should work on the
+implementation of trees you designed in the previous step, and it
+should make use of the list comparison function you wrote for question
+2. Thus you'll have to make sure you only use Church numerals as the
+labels of your leaves, though nothing enforces this self-discipline.
-Write the fringe-enumeration function. It should work on the implementation of
-trees you designed in the previous step.
</OL>
notes](/week3/#index4h2) as a model, construct a pair `Y1` and `Y2` that behave
in the way described.
-(See [[hints/Assignment 4 hint 4]] if you need some hints.)
+(See [[hints/Assignment 4 hint 3]] if you need some hints.)
</OL>