Module BAF := BA_Facts BA.(* Now, we prove the axioms about relativization.
     Again, this mostly involves packing and unpacking
     the canonTree type and pushing around mkCanon.
   *)

    Definition rel (a x:t) : t.

Lemma rel_preserves_glb : forall a x y, rel a (glb x y) = glb (rel a x) (rel a y).