YES(?,O(n^2))
TRS:
 {-(+(x, y), y) -> x,
  +(-(x, y), z) -> -(+(x, z), y)}
 DUP: We consider a non-duplicating system.
  Trs:
   {-(+(x, y), y) -> x,
    +(-(x, y), z) -> -(+(x, z), y)}
  Matrix Interpretation:
   Interpretation class: triangular
       [X3]  [X1]    [1 3][X3]   [1 0][X1]   [0]
   [+]([X2], [X0]) = [0 1][X2] + [0 0][X0] + [0]
   
       [X3]  [X1]    [1 1][X3]   [1 1][X1]   [1]
   [-]([X2], [X0]) = [0 1][X2] + [0 1][X0] + [3]
   
   
   Qed