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