start with the `isZero` predicate, and only produce a fresh copy of
`prefac` if we are forced to.
start with the `isZero` predicate, and only produce a fresh copy of
`prefac` if we are forced to.
-#Q. You claimed that the Ackerman function couldn't be implemented
-using our primitive recursion techniques (such as the techniques that
-allow us to define addition and multiplication). But you haven't
-shown that it is possible to define the Ackerman function using full
-recursion.#
+#Q. You claimed that the Ackerman function couldn't be implemented using our primitive recursion techniques (such as the techniques that allow us to define addition and multiplication). But you haven't shown that it is possible to define the Ackerman function using full recursion.#