update in ground_2 and basic_2

[helm.git] / matita / matita / contribs / lambdadelta / basic_2 / etc / fid / fid.etc

diff --git a/matita/matita/contribs/lambdadelta/basic_2/etc/fid/fid.etc b/matita/matita/contribs/lambdadelta/basic_2/etc/fid/fid.etc
new file mode 100644 (file)
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+(**************************************************************************)
+(*       ___                                                              *)
+(*      ||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/notation/relations/isidentity_2.ma".
+include "basic_2/static/frees.ma".
+
+(* FREE VARIABLES IDENTITY FOR RESTRICTED CLOSURES **************************)
+
+definition fid: relation2 … ≝ λL,T.
+                ∀f. L ⊢ 𝐅*⦃T⦄ ≡ f →  𝐈⦃f⦄.
+
+interpretation "free variables identity (restricted closure)"
+   'IsIdentity L T = (fid L T).
+
+(* Basic properties *********************************************************)
+
+lemma fid_sort: ∀L,s. 𝐈⦃L, ⋆s⦄.
+/2 width=3 by frees_inv_sort/ qed.
+
+lemma fid_gref: ∀L,l. 𝐈⦃L, §l⦄.
+/2 width=3 by frees_inv_gref/ qed.