MAYBE We are left with following problem, upon which TcT provides the certificate MAYBE. Strict Trs: { f(0()) -> s(0()) , f(s(x)) -> g(s(s(x))) , g(0()) -> s(0()) , g(s(0())) -> s(0()) , g(s(s(x))) -> f(x) } Obligation: innermost runtime complexity Answer: MAYBE The input cannot be shown compatible Arrrr..