YES(?,O(n^2))
TRS:
 {
              f X -> n__f X,
            f 0() -> cons(0(), n__f n__s n__0()),
          f s 0() -> f p s 0(),
              0() -> n__0(),
          p s 0() -> 0(),
              s X -> n__s X,
       activate X -> X,
  activate n__f X -> f activate X,
  activate n__s X -> s activate X,
  activate n__0() -> 0()
 }
 DUP: We consider a non-duplicating system.
  Trs:
   {
                f X -> n__f X,
              f 0() -> cons(0(), n__f n__s n__0()),
            f s 0() -> f p s 0(),
                0() -> n__0(),
            p s 0() -> 0(),
                s X -> n__s X,
         activate X -> X,
    activate n__f X -> f activate X,
    activate n__s X -> s activate X,
    activate n__0() -> 0()
   }
  Matrix Interpretation:
   Interpretation class: triangular
              [X1]    [1 3][X1]   [3]
   [activate]([X0]) = [0 1][X0] + [3]
   
       [X1]    [1 0][X1]   [2]
   [s]([X0]) = [0 1][X0] + [1]
   
       [X1]    [1 0][X1]   [0]
   [p]([X0]) = [0 0][X0] + [2]
   
            [0]
   [n__0] = [0]
   
          [X1]    [1 0][X1]   [0]
   [n__s]([X0]) = [0 1][X0] + [1]
   
          [X1]    [1 2][X1]   [0]
   [n__f]([X0]) = [0 1][X0] + [3]
   
         [2]
   [0] = [2]
   
          [X3]  [X1]    [1 0][X3]   [1 0][X1]   [0]
   [cons]([X2], [X0]) = [0 0][X2] + [0 0][X0] + [0]
   
       [X1]    [1 2][X1]   [2]
   [f]([X0]) = [0 1][X0] + [3]
   
   
   Qed