X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;ds=sidebyside;f=matita%2Fmatita%2Fcontribs%2Flambdadelta%2Fdelayed_updating%2Freduction%2Fifr.ma;h=582f6ed5761ff450a54d34d6b113c5c07e9aaaa1;hb=2cc4eb5d0210be58286e028278852122dcb68052;hp=d087bdbb736fd4aea41de56ae86ef8e249a5f1cd;hpb=513a56a5990201abcf038e7242779e2d73621c86;p=helm.git

diff --git a/matita/matita/contribs/lambdadelta/delayed_updating/reduction/ifr.ma b/matita/matita/contribs/lambdadelta/delayed_updating/reduction/ifr.ma
index d087bdbb7..582f6ed57 100644
--- a/matita/matita/contribs/lambdadelta/delayed_updating/reduction/ifr.ma
+++ b/matita/matita/contribs/lambdadelta/delayed_updating/reduction/ifr.ma
@@ -21,10 +21,11 @@ include "delayed_updating/notation/relations/black_rightarrow_f_4.ma".
 
 (* IMMEDIATE FOCUSED REDUCTION ************************************************)
 
-inductive ifr (p) (q) (t): predicate prototerm ≝
-| ifr_beta (b):
-  let r ≝ p●𝗔◗b●𝗟◗q in
-  r◖𝗱(↑❘q❘) ϵ t → ⊓(⊗b) → ifr p q t (t[⋔r←↑[𝐮❨↑❘q❘❩]t⋔(p◖𝗦)])
+definition ifr (p) (q): relation2 prototerm prototerm ≝
+           λt1,t2. ∃b.
+           let r ≝ p●𝗔◗b●𝗟◗q in
+           ∧∧ ⊓(⊗b) & r◖𝗱(↑❘q❘) ϵ t1 &
+              t2 ⇔ t1[⋔r←↑[𝐮❨↑❘q❘❩]t1⋔(p◖𝗦)]
 .
 
 interpretation