MAYBE We are left with following problem, upon which TcT provides the certificate MAYBE. Strict Trs: { g(A()) -> A() , g(B()) -> A() , g(B()) -> B() , g(C()) -> A() , g(C()) -> B() , g(C()) -> C() , foldB(t, 0()) -> t , foldB(t, s(n)) -> f(foldB(t, n), B()) , f(t, x) -> f'(t, g(x)) , foldC(t, 0()) -> t , foldC(t, s(n)) -> f(foldC(t, n), C()) , f'(triple(a, b, c), A()) -> f''(foldB(triple(s(a), 0(), c), b)) , f'(triple(a, b, c), B()) -> f(triple(a, b, c), A()) , f'(triple(a, b, c), C()) -> triple(a, b, s(c)) , f''(triple(a, b, c)) -> foldC(triple(a, b, 0()), c) , fold(t, x, 0()) -> t , fold(t, x, s(n)) -> f(fold(t, x, n), x) } Obligation: innermost runtime complexity Answer: MAYBE The input cannot be shown compatible Arrrr..