(STRATEGY
    INNERMOST)

(VAR
    x y z)
(DATATYPES
    A = µX.< 0, s(X) >)
(SIGNATURES
    min :: [A x A] -> A
    max :: [A x A] -> A
    minus :: [A x A] -> A
    gcd :: [A x A] -> A
    transform :: [A] -> A
    cons :: [A x A] -> A)
(RULES
    min(x,0()) -> 0()
    min(0(),y) -> 0()
    min(s(x),s(y)) -> s(min(x,y))
    max(x,0()) -> x
    max(0(),y) -> y
    max(s(x),s(y)) -> s(max(x,y))
    minus(x,0()) -> x
    minus(s(x),s(y)) -> s(minus(x
                               ,y))
    gcd(s(x),s(y)) ->
      gcd(minus(max(x,y)
               ,min(x,transform(y)))
         ,s(min(x,y)))
    transform(x) -> s(s(x))
    transform(cons(x,y)) ->
      cons(cons(x,x),x)
    transform(cons(x,y)) -> y
    transform(s(x)) ->
      s(s(transform(x)))
    cons(x,y) -> y
    cons(x,cons(y,s(z))) -> cons(y
                                ,x)
    cons(cons(x,z),s(y)) ->
      transform(x))