MAYBE We are left with following problem, upon which TcT provides the certificate MAYBE. Strict Trs: { 2nd(cons1(X, cons(Y, Z))) -> Y , 2nd(cons(X, X1)) -> 2nd(cons1(X, activate(X1))) , activate(X) -> X , activate(n__from(X)) -> from(activate(X)) , activate(n__s(X)) -> s(activate(X)) , from(X) -> cons(X, n__from(n__s(X))) , from(X) -> n__from(X) , s(X) -> n__s(X) } Obligation: innermost runtime complexity Answer: MAYBE The input cannot be shown compatible Arrrr..