(STRATEGY
    INNERMOST)

(VAR
    k l x y z)
(DATATYPES
    A = µX.< nil, cons(X, X), h, s(X) >)
(SIGNATURES
    app :: [A x A] -> A
    sum :: [A] -> A
    a :: [A x A x A] -> A)
(RULES
    app(nil(),k) -> k
    app(l,nil()) -> l
    app(cons(x,l),k) -> cons(x
                            ,app(l,k))
    sum(cons(x,nil())) -> cons(x
                              ,nil())
    sum(cons(x,cons(y,l))) ->
      sum(cons(a(x,y,h()),l))
    a(h(),h(),x) -> s(x)
    a(x,s(y),h()) -> a(x,y,s(h()))
    a(x,s(y),s(z)) -> a(x
                       ,y
                       ,a(x,s(y),z))
    a(s(x),h(),z) -> a(x,z,z))