MAYBE MAYBE 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) } DUP: We consider a duplicating system. 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) } Fail