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