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