MAYBE
MAYBE
TRS:
 {
               first(X1, X2) -> n__first(X1, X2),
               first(0(), X) -> nil(),
     first(s(X), cons(Y, Z)) -> cons(Y, n__first(X, activate(Z))),
                 activate(X) -> X,
  activate(n__first(X1, X2)) -> first(X1, X2),
        activate(n__from(X)) -> from(X),
                     from(X) -> cons(X, n__from(s(X))),
                     from(X) -> n__from(X)
 }
 DUP: We consider a duplicating system.
  Trs:
   {
                 first(X1, X2) -> n__first(X1, X2),
                 first(0(), X) -> nil(),
       first(s(X), cons(Y, Z)) -> cons(Y, n__first(X, activate(Z))),
                   activate(X) -> X,
    activate(n__first(X1, X2)) -> first(X1, X2),
          activate(n__from(X)) -> from(X),
                       from(X) -> cons(X, n__from(s(X))),
                       from(X) -> n__from(X)
   }
  Fail