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