update in delayed_updating

[helm.git] / matita / matita / contribs / lambdadelta / delayed_updating / etc / core_reduction / ifr.etc

diff --git a/matita/matita/contribs/lambdadelta/delayed_updating/etc/core_reduction/ifr.etc b/matita/matita/contribs/lambdadelta/delayed_updating/etc/core_reduction/ifr.etc
new file mode 100644 (file)
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--- /dev/null
+++ b/matita/matita/contribs/lambdadelta/delayed_updating/etc/core_reduction/ifr.etc
@@ -0,0 +1,34 @@
+(**************************************************************************)
+(*       ___                                                              *)
+(*      ||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/substitution/fsubst.ma".
+include "delayed_updating/substitution/lift_prototerm.ma".
+include "delayed_updating/syntax/prototerm_eq.ma".
+include "delayed_updating/syntax/path_closed.ma".
+include "delayed_updating/notation/relations/black_rightarrow_if_3.ma".
+include "ground/relocation/tr_uni.ma".
+include "ground/xoa/ex_4_3.ma".
+
+(* IMMEDIATE FOCUSED REDUCTION ************************************************)
+
+definition ifr (r): relation2 prototerm prototerm ≝
+           λt1,t2.
+           ∃∃p,q,n. p●𝗔◗𝗟◗q = r &
+           q ϵ 𝐂❨Ⓕ,n❩ & r◖𝗱↑n ϵ t1 &
+           t1[⋔r←🠡[𝐮❨↑n❩](t1⋔(p◖𝗦))] ⇔ t2
+.
+
+interpretation
+  "focused reduction with immediate updating (prototerm)"
+  'BlackRightArrowIF t1 r t2 = (ifr r t1 t2).