update in delayed_updating

[helm.git] / matita / matita / contribs / lambdadelta / delayed_updating / unwind / unwind2_constructors.ma

diff --git a/matita/matita/contribs/lambdadelta/delayed_updating/unwind/unwind2_constructors.ma b/matita/matita/contribs/lambdadelta/delayed_updating/unwind/unwind2_constructors.ma
new file mode 100644 (file)
index 0000000..c70e09e
--- /dev/null
+++ b/matita/matita/contribs/lambdadelta/delayed_updating/unwind/unwind2_constructors.ma
@@ -0,0 +1,39 @@
+(**************************************************************************)
+(*       ___                                                              *)
+(*      ||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 "delayed_updating/unwind/unwind2_prototerm_eq.ma".
+include "delayed_updating/syntax/prototerm_constructors.ma".
+
+(* UNWIND FOR PROTOTERM *****************************************************)
+
+(* Constructions with constructors ******************************************)
+
+lemma unwind2_term_iref_sn (f) (t) (n:pnat):
+      ▼[f∘𝐮❨n❩]t ⊆ ▼[f](𝛗n.t).
+#f #t #n #p * #q #Hq #H0 destruct
+@(ex2_intro … (𝗱n◗𝗺◗q))
+/2 width=1 by in_comp_iref/
+qed-.
+
+lemma unwind2_term_iref_dx (f) (t) (n:pnat):
+      ▼[f](𝛗n.t) ⊆ ▼[f∘𝐮❨n❩]t.
+#f #t #n #p * #q #Hq #H0 destruct
+elim (in_comp_inv_iref … Hq) -Hq #p #Hp #Ht destruct
+/2 width=1 by in_comp_unwind2_path_term/
+qed-.
+
+lemma unwind2_term_iref (f) (t) (n:pnat):
+      ▼[f∘𝐮❨n❩]t ⇔ ▼[f](𝛗n.t).
+/3 width=2 by conj, unwind2_term_iref_sn, unwind2_term_iref_dx/
+qed.