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