YES
O(n^3)
TRS:
 {
              __(X, nil()) -> X,
           __(__(X, Y), Z) -> __(X, __(Y, Z)),
              __(nil(), X) -> X,
                 U12(tt()) -> tt(),
                 U11(tt()) -> U12(tt()),
  isNePal(__(I, __(P, I))) -> U11(tt())
 }
 DUP: We consider a non-duplicating system.
  Trs:
   {
                __(X, nil()) -> X,
             __(__(X, Y), Z) -> __(X, __(Y, Z)),
                __(nil(), X) -> X,
                   U12(tt()) -> tt(),
                   U11(tt()) -> U12(tt()),
    isNePal(__(I, __(P, I))) -> U11(tt())
   }
  Matrix Interpretation:
   Interpretation class: triangular
             [X2]    [1 1 0][X2]   [1]
   [isNePal]([X1]) = [0 0 0][X1] + [1]
             [X0]    [0 0 0][X0]   [1]
   
         [X2]    [1 1 0][X2]   [1]
   [U11]([X1]) = [0 1 0][X1] + [0]
         [X0]    [0 0 0][X0]   [1]
   
          [0]
   [tt] = [1]
          [0]
   
         [X2]    [1 0 0][X2]   [1]
   [U12]([X1]) = [0 0 0][X1] + [1]
         [X0]    [0 0 0][X0]   [1]
   
           [1]
   [nil] = [1]
           [0]
   
        [X5]  [X2]    [1 1 0][X5]   [1 0 0][X2]   [0]
   [__]([X4], [X1]) = [0 1 0][X4] + [0 1 0][X1] + [1]
        [X3]  [X0]    [0 0 1][X3]   [0 0 1][X0]   [0]
   
   
   Qed