YES(?,O(n^2))
TRS:
 {f s x -> s s g x,
  f 0() -> s 0(),
  g s x -> f x,
  g 0() -> 0()}
 DUP: We consider a non-duplicating system.
  Trs:
   {f s x -> s s g x,
    f 0() -> s 0(),
    g s x -> f x,
    g 0() -> 0()}
  Matrix Interpretation:
   Interpretation class: triangular
         [0]
   [0] = [0]
   
       [X1]    [1 0][X1]   [0]
   [s]([X0]) = [0 1][X0] + [2]
   
       [X1]    [1 2][X1]   [1]
   [g]([X0]) = [0 1][X0] + [0]
   
       [X1]    [1 2][X1]   [2]
   [f]([X0]) = [0 1][X0] + [2]
   
   
   Qed