MAYBE We are left with following problem, upon which TcT provides the certificate MAYBE. Strict Trs: { zeros() -> cons(0(), n__zeros()) , zeros() -> n__zeros() , and(tt(), X) -> activate(X) , activate(X) -> X , activate(n__zeros()) -> zeros() , length(cons(N, L)) -> s(length(activate(L))) , length(nil()) -> 0() } Obligation: innermost runtime complexity Answer: MAYBE The input cannot be shown compatible Arrrr..