intros.
unfold unlink_acl in |- *.
elim (facl (acl s) o1).
intros; unfold facl in |- *; apply RemEq.
auto.
auto.
Qed.

(* Specifications: *)
(*Seguir aqui*)
Lemma Eqfacl4 :
forall (s : SFSstate) (o : OBJECT) (y z : AccessCtrlListData),
FuncPre4 s ->
facl (acl s) o = Some y -> facl (rmdir_acl s o) o = Some z -> False.