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