YES
O(n^5)
TRS:
 {app(app(app(compose(), f), g), x) -> app(f, app(g, x))}
 DUP: We consider a non-duplicating system.
  Trs:
   {app(app(app(compose(), f), g), x) -> app(f, app(g, x))}
  Matrix Interpretation:
   Interpretation class: triangular
               [0]
               [0]
   [compose] = [0]
               [0]
               [0]
   
         [X9]  [X4]    [1 0 1 0 0][X9]   [1 0 0 0 0][X4]   [0]
         [X8]  [X3]    [0 0 0 0 0][X8]   [0 0 0 0 0][X3]   [0]
   [app]([X7], [X2]) = [0 0 0 0 1][X7] + [0 0 1 0 0][X2] + [0]
         [X6]  [X1]    [0 0 0 0 0][X6]   [0 0 0 0 0][X1]   [0]
         [X5]  [X0]    [0 0 0 0 1][X5]   [0 0 0 0 1][X0]   [1]
   
   
   Qed