- degree-based equivalene for terms

[helm.git] / matita / matita / contribs / lambdadelta / basic_2 / etc_2A1 / xpr / xprs_aaa.etc

diff --git a/matita/matita/contribs/lambdadelta/basic_2/etc_2A1/xpr/xprs_aaa.etc b/matita/matita/contribs/lambdadelta/basic_2/etc_2A1/xpr/xprs_aaa.etc
new file mode 100644 (file)
index 0000000..5beb8fe
--- /dev/null
+++ b/matita/matita/contribs/lambdadelta/basic_2/etc_2A1/xpr/xprs_aaa.etc
@@ -0,0 +1,24 @@
+(**************************************************************************)
+(*       ___                                                              *)
+(*      ||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/reducibility/xpr_aaa.ma".
+include "basic_2/computation/xprs.ma".
+
+(* EXTENDED PARALLEL COMPUTATION ON TERMS ***********************************)
+
+(* Properties on atomic arity assignment for terms **************************)
+
+lemma xprs_aaa: ∀h,g,L,T,A. L ⊢ T ⁝ A → ∀U. ⦃h, L⦄ ⊢ T •➡*[g] U → L ⊢ U ⁝ A.
+#h #g #L #T #A #HT #U #H @(xprs_ind … H) -U // /2 width=5/
+qed.