YES

TRS:

  __(__(X,Y),Z) -> __(X,__(Y,Z))
  __(X,nil()) -> X
  __(nil(),X) -> X
  U11(tt()) -> U12(tt())
  U12(tt()) -> tt()
  isNePal(__(I,__(P,I))) -> U11(tt())
  activate(X) -> X

linear polynomial interpretations on N:

  ___A(x1,x2) = x1 + x2 + 1
  __#_A(x1,x2) = 3
  nil_A = 0
  nil#_A = 0
  U11_A(x1) = 1
  U11#_A(x1) = 2
  tt_A = 1
  tt#_A = 0
  U12_A(x1) = 1
  U12#_A(x1) = 1
  isNePal_A(x1) = 1
  isNePal#_A(x1) = 3
  activate_A(x1) = x1
  activate#_A(x1) = x1

precedence:

  __ = isNePal > U11 > U12 > nil = tt = activate