YES
O(n^2)
TRS:
 {g(a(), x) -> f(b(), x),
  f(a(), x) -> g(a(), x),
  f(a(), x) -> f(b(), x)}
 DUP: We consider a non-duplicating system.
  Trs:
   {g(a(), x) -> f(b(), x),
    f(a(), x) -> g(a(), x),
    f(a(), x) -> f(b(), x)}
  Matrix Interpretation:
   Interpretation class: triangular
         [0]
   [b] = [0]
   
       [X3]  [X1]    [1 1][X3]   [1 0][X1]   [0]
   [f]([X2], [X0]) = [0 0][X2] + [0 0][X0] + [0]
   
         [1]
   [a] = [1]
   
       [X3]  [X1]    [1 0][X3]   [1 0][X1]   [0]
   [g]([X2], [X0]) = [0 0][X2] + [0 0][X0] + [0]
   
   
   Qed