YES
O(n^2)
TRS:
 {f(a()) -> g(a()),
     b() -> a(),
  g(b()) -> f(b())}
 DUP: We consider a non-duplicating system.
  Trs:
   {f(a()) -> g(a()),
       b() -> a(),
    g(b()) -> f(b())}
  Matrix Interpretation:
   Interpretation class: triangular
         [0]
   [a] = [0]
   
       [X1]    [1 3][X1]   [0]
   [g]([X0]) = [0 1][X0] + [0]
   
         [1]
   [b] = [2]
   
       [X1]    [1 1][X1]   [2]
   [f]([X0]) = [0 0][X0] + [0]
   
   
   Qed