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)) , +(0(), y) -> y , +(s(x), y) -> s(+(x, y)) , -(x, 0()) -> x , -(s(x), s(y)) -> -(x, y) , *(x, 0()) -> 0() , *(x, s(y)) -> +(x, *(x, y)) , f(s(x)) -> f(-(max(*(s(x), s(x)), +(s(x), s(s(s(0()))))), max(s(*(s(x), s(x))), +(s(x), s(s(s(s(0())))))))) } Obligation: innermost runtime complexity Answer: MAYBE The input cannot be shown compatible Arrrr..