- we set up the support for the "bt-reduction" of Automath literature

[helm.git] / matita / matita / contribs / lambda_delta / basic_2 / computation / yprs_xprs.ma

diff --git a/matita/matita/contribs/lambda_delta/basic_2/computation/yprs_xprs.ma b/matita/matita/contribs/lambda_delta/basic_2/computation/yprs_xprs.ma
new file mode 100644 (file)
index 0000000..2feb88a
--- /dev/null
+++ b/matita/matita/contribs/lambda_delta/basic_2/computation/yprs_xprs.ma
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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/computation/xprs_cprs.ma".
+include "basic_2/computation/yprs.ma".
+
+(* HYPER PARALLEL COMPUTATION ON CLOSURES ***********************************)
+
+(* Properties on extended parallel computation for terms ********************)
+
+lemma xprs_yprs: ∀h,g,L,T1,T2. ⦃h, L⦄ ⊢ T1 •➡*[g] T2 →
+                 h ⊢ ⦃L, T1⦄ •⥸*[g] ⦃L, T2⦄.
+#h #g #L #T1 #T2 #H @(xprs_ind … H) -T2 // /3 width=4/
+qed.
+
+lemma cprs_yprs: ∀h,g,L,T1,T2. L ⊢ T1 ➡* T2 → h ⊢ ⦃L, T1⦄ •⥸*[g] ⦃L, T2⦄.
+/3 width=1/ qed.