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