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.
+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.
+implementation of trees you designed in the previous step.
+Then combine this with the list comparison function you wrote for question 2,
+to yield a same-fringe detector. (To use your list comparison function, you'll
+have to make sure you only use Church numerals as the labels of your leaves,
+though nothing enforces this self-discipline.)
</OL>