we started Kashima's proof of standardization

[helm.git] / matita / matita / contribs / lambda / st_computation.ma

diff --git a/matita/matita/contribs/lambda/st_computation.ma b/matita/matita/contribs/lambda/st_computation.ma
new file mode 100644 (file)
index 0000000..792ab88
--- /dev/null
+++ b/matita/matita/contribs/lambda/st_computation.ma
@@ -0,0 +1,27 @@
+(**************************************************************************)
+(*       ___                                                              *)
+(*      ||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 "hap_computation.ma".
+
+(* KASHIMA'S "ST" COMPUTATION ***********************************************)
+
+(* Note: this is the "standard" computation of:
+         R. Kashima: "A proof of the Standization Theorem in λ-Calculus". Typescript note, (2000).
+*)
+inductive st: relation term ≝
+| st_vref: ∀M,i. hap M (#i) → st M (#i)
+| st_abst: ∀M,A,C. hap M (𝛌.A) → st A C → st M (𝛌.C)
+| st_appl: ∀M,B,D,A,C. hap M (@B.A) → st B D → st A C → st M (@D.C) 
+.
+