MAYBE We are left with following problem, upon which TcT provides the certificate MAYBE. Strict Trs: { f(true(), x, y, z) -> f(gt(x, plus(y, z)), x, y, s(z)) , f(true(), x, y, z) -> f(gt(x, plus(y, z)), x, s(y), z) , gt(s(u), s(v)) -> gt(u, v) , gt(s(u), 0()) -> true() , gt(0(), v) -> false() , plus(n, s(m)) -> s(plus(n, m)) , plus(n, 0()) -> n } Obligation: innermost runtime complexity Answer: MAYBE The input cannot be shown compatible Arrrr..