From: Claudio Sacerdoti Coen <claudio.sacerdoticoen@unibo.it>
Date: Tue, 12 Sep 2006 13:19:19 +0000 (+0000)
Subject: Foo is the problematic elimination principle.
X-Git-Tag: 0.4.95@7852~1047
X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=commitdiff_plain;h=4199a9a1b1f28e0b29e532324c08e358311424b9;p=helm.git

Foo is the problematic elimination principle.
---

diff --git a/matita/contribs/LAMBDA-TYPES/Level-1/problems.ma b/matita/contribs/LAMBDA-TYPES/Level-1/problems.ma
index 0e740a878..bc0d10fee 100644
--- a/matita/contribs/LAMBDA-TYPES/Level-1/problems.ma
+++ b/matita/contribs/LAMBDA-TYPES/Level-1/problems.ma
@@ -25,7 +25,24 @@ include "LambdaDelta/theory.ma".
 
 (* Problem 2: assertion failure raised by type checker on this object *)
 
+definition foo ≝
+\lambda g:G.\lambda c:C.\lambda t:T.
+\lambda P:T\to Prop.
+\lambda H:\forall t1:T.\forall H:tau0 g c t t1.P t1.
+\lambda H1:
+ \forall t1:T.\forall H1:tau1 g c t t1.
+  P t1 \to \forall t2:T.\forall H2:tau0 g c t1 t2.P t2.
+ let rec f (t1:T) (H2:tau1 g c t t1) on H2 ≝
+  match H2 return \lambda t2:T.\lambda H3:tau1 g c t t2.P t2 with
+  [ tau1_tau0 => \lambda t2:T.\lambda H3:(tau0 g c t t2).H t2 H3
+  | tau1_sing =>
+     \lambda t2:T.\lambda H3:(tau1 g c t t2).\lambda t3:T.
+      \lambda H4:tau0 g c t2 t3.H1 t2 H3 (f t2 H3) t3 H4
+  ]
+ in f.
+
+
 inductive tau1 (g:G) (c:C) (t1:T): T \to Prop \def
 | tau1_tau0: \forall (t2: T).((tau0 g c t1 t2) \to (tau1 g c t1 t2))
 | tau1_sing: \forall (t: T).((tau1 g c t1 t) \to (\forall (t2: T).((tau0 g c 
-t t2) \to (tau1 g c t1 t2)))).
+t t2) \to (tau1 g c t1 t2))))).