(STRATEGY
    INNERMOST)

(VAR
    x y)
(DATATYPES
    A = µX.< 0, s(X) >)
(SIGNATURES
    minus :: [A x A] -> A
    double :: [A] -> A
    plus :: [A x A] -> A)
(RULES
    minus(x,0()) -> x
    minus(s(x),s(y)) -> minus(x,y)
    double(0()) -> 0()
    double(s(x)) -> s(s(double(x)))
    plus(0(),y) -> y
    plus(s(x),y) -> s(plus(x,y))
    plus(s(x),y) -> plus(x,s(y))
    plus(s(x),y) -> s(plus(minus(x
                                ,y)
                          ,double(y))))