(STRATEGY
    INNERMOST)

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