Problem:
 h(X) -> g(X,X)
 g(a(),X) -> f(b(),activate(X))
 f(X,X) -> h(a())
 a() -> b()
 activate(X) -> X

Proof:
 Unfolding Processor:
  loop length: 5
  terms:
   h(a())
   g(a(),a())
   f(b(),activate(a()))
   f(b(),a())
   f(b(),b())
  context: []
  substitution:
   
  Qed