TRS:
 {   a__f(X) -> g(h(f(X))),
  mark(f(X)) -> a__f(mark(X)),
  mark(g(X)) -> g(X),
  mark(h(X)) -> h(mark(X)),
     a__f(X) -> f(X)}
 MPO:
  Prec:
   a__f > g, 
   a__f > h, 
   a__f > f, 
   mark > a__f, 
   mark > h
   empty
  Strict:
   {}
   Weak:
    {}
  Qed