YES

TRS:

  f(f(a())) -> f(g(n__f(a())))
  f(X) -> n__f(X)
  activate(n__f(X)) -> f(X)
  activate(X) -> X

linear polynomial interpretations on N:

  f_A(x1) = x1 + 1
  f#_A(x1) = x1 + 2
  a_A = 1
  a#_A = 0
  g_A(x1) = 0
  g#_A(x1) = x1
  n__f_A(x1) = x1 + 1
  n__f#_A(x1) = 1
  activate_A(x1) = x1
  activate#_A(x1) = x1 + 2

precedence:

  activate > f > a = g = n__f