(STRATEGY
    INNERMOST)

(VAR
    x y)
(DATATYPES
    A = µX.< t, 1, constant, 0, +(X, X), *(X, X), -(X, X) >)
(SIGNATURES
    D :: [A] -> A)
(RULES
    D(t()) -> 1()
    D(constant()) -> 0()
    D(+(x,y)) -> +(D(x),D(y))
    D(*(x,y)) -> +(*(y,D(x))
                  ,*(x,D(y)))
    D(-(x,y)) -> -(D(x),D(y)))