(STRATEGY
    INNERMOST)

(VAR
    x y)
(DATATYPES
    A = µX.< 0, s(X) >)
(SIGNATURES
    plus :: [A x A] -> A
    times :: [A x A] -> A
    p :: [A] -> A
    fac :: [A x A] -> A
    factorial :: [A] -> A)
(RULES
    plus(0(),x) -> x
    plus(s(x),y) -> s(plus(p(s(x))
                          ,y))
    times(0(),y) -> 0()
    times(s(x),y) -> plus(y
                         ,times(p(s(x)),y))
    p(s(0())) -> 0()
    p(s(s(x))) -> s(p(s(x)))
    fac(0(),x) -> x
    fac(s(x),y) -> fac(p(s(x))
                      ,times(s(x),y))
    factorial(x) -> fac(x,s(0())))