tauto.
Qed.

(* Specifications: *)
(** ~ is reflexive, ... *)
Lemma equiv_refl : forall h : hedge, equiv_h h h.
unfold equiv_h in |- *.
(** if g <= h then g is included in S(h) *)
Lemma le_h_impl_incl_syn :
forall g h : hedge, le_h g h -> inclusion g (synthesis h).