YES
O(n^2)
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
             [X1]    [1 0][X1]   [1]
   [isNePal]([X0]) = [0 1][X0] + [0]
   
         [X1]    [1 1][X1]   [1]
   [U11]([X0]) = [0 1][X0] + [1]
   
          [0]
   [tt] = [1]
   
         [X1]    [1 0][X1]   [1]
   [U12]([X0]) = [0 1][X0] + [0]
   
           [0]
   [nil] = [0]
   
        [X3]  [X1]    [1 1][X3]   [1 0][X1]   [1]
   [__]([X2], [X0]) = [0 1][X2] + [0 1][X0] + [1]
   
   
   Qed