elim H.
red in |- *; simpl in |- *; exact I.
intros.
change (dans e X /\ Inmonoid X w0) in |- *.
auto.
Qed.
Hint Resolve i_I.

Lemma I_i : forall (X : Ensf) (w : Word), Inmonoid X w -> inmonoid X w.
intros X.