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) , mod(x, 0()) -> modZeroErro() , mod(x, s(y)) -> modIter(x, s(y), 0(), 0()) , modIter(x, s(y), z, u) -> if(le(x, z), x, s(y), z, u) , if(true(), x, y, z, u) -> u , if(false(), x, y, z, u) -> if2(le(y, s(u)), x, y, s(z), s(u)) , if2(true(), x, y, z, u) -> modIter(x, y, z, 0()) , if2(false(), x, y, z, u) -> modIter(x, y, z, u) } Obligation: innermost runtime complexity Answer: MAYBE The input cannot be shown compatible Arrrr..