--- /dev/null
+(**************************************************************************)
+(* ___ *)
+(* ||M|| *)
+(* ||A|| A project by Andrea Asperti *)
+(* ||T|| *)
+(* ||I|| Developers: *)
+(* ||T|| The HELM team. *)
+(* ||A|| http://helm.cs.unibo.it *)
+(* \ / *)
+(* \ / This file is distributed under the terms of the *)
+(* v GNU General Public License Version 2 *)
+(* *)
+(**************************************************************************)
+
+include "basic_2/static/frees_fqup.ma".
+include "basic_2/static/fle.ma".
+
+(* FREE VARIABLES INCLUSION FOR RESTRICTED CLOSURES *************************)
+
+(* Advanced properties ******************************************************)
+
+lemma fle_refl: bi_reflexive … fle.
+#L #T elim (frees_total L T) /2 width=5 by sle_refl, ex3_2_intro/
+qed.
+
+lemma fle_bind_sn: ∀p,I,L,V,T. ⦃L, V⦄ ⊆ ⦃L, ⓑ{p,I}V.T⦄.
+#p #I #L #V #T
+elim (frees_total L V) #f1 #Hf1
+elim (frees_total (L.ⓑ{I}V) T) #f2 #Hf2
+elim (sor_isfin_ex f1 (⫱f2)) /3 width=3 by frees_fwd_isfin, isfin_tl/ #f #Hf #_
+/3 width=6 by frees_bind, sor_inv_sle_sn, ex3_2_intro/
+qed.
+
+lemma fle_flat_sn: ∀I,L,V,T. ⦃L, V⦄ ⊆ ⦃L, ⓕ{I}V.T⦄.
+#I #L #V #T
+elim (frees_total L V) #f1 #Hf1
+elim (frees_total L T) #f2 #Hf2
+elim (sor_isfin_ex f1 f2) /2 width=3 by frees_fwd_isfin/ #f #Hf #_
+/3 width=6 by frees_flat, sor_inv_sle_sn, ex3_2_intro/
+qed.
+
+lemma fle_flat_dx: ∀I,L,V,T. ⦃L, T⦄ ⊆ ⦃L, ⓕ{I}V.T⦄.
+#I #L #V #T
+elim (frees_total L V) #f1 #Hf1
+elim (frees_total L T) #f2 #Hf2
+elim (sor_isfin_ex f1 f2) /2 width=3 by frees_fwd_isfin/ #f #Hf #_
+/3 width=6 by frees_flat, sor_inv_sle_dx, ex3_2_intro/
+qed.