YES(?,O(n^1))
TRS:
 {
              zeros() -> cons(0(), n__zeros()),
              zeros() -> n__zeros(),
           activate X -> X,
  activate n__zeros() -> zeros(),
     tail cons(X, XS) -> activate XS
 }
 DUP: We consider a non-duplicating system.
  Trs:
   {
                zeros() -> cons(0(), n__zeros()),
                zeros() -> n__zeros(),
             activate X -> X,
    activate n__zeros() -> zeros(),
       tail cons(X, XS) -> activate XS
   }
  Natural interpretation:
   Strict:
    {
                 zeros() -> cons(0(), n__zeros()),
                 zeros() -> n__zeros(),
              activate X -> X,
     activate n__zeros() -> zeros(),
        tail cons(X, XS) -> activate XS
    }
   Weak:
    {}
   Interpretation class: stronglylinear
   [tail](X0) = + 1*X0 + 7
   [activate](X0) = + 1*X0 + 7
   [zeros] = + 4
   [n__zeros] = + 2
   [0] = + 0
   [cons](X1, X0) = + 1*X0 + 1*X1 + 1
   
   Qed