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update in delayed_updating
[helm.git] / matita / matita / contribs / lambdadelta / delayed_updating / reduction / dfr.ma
index b7f900b6c6a870b1b7f1c6c27692918525e0d703..7ae112491e80dd44a99080e6a7e5fa3f7baa81d5 100644 (file)
 (*                                                                        *)
 (**************************************************************************)
 
-include "delayed_updating/unwind1/unwind.ma".
 include "delayed_updating/substitution/fsubst.ma".
 include "delayed_updating/syntax/prototerm_constructors.ma".
 include "delayed_updating/syntax/prototerm_equivalence.ma".
-include "delayed_updating/syntax/path_structure.ma".
-include "delayed_updating/syntax/path_balanced.ma".
+include "delayed_updating/syntax/path_head.ma".
 include "delayed_updating/syntax/path_depth.ma".
+include "delayed_updating/syntax/path_reverse.ma".
 include "delayed_updating/notation/relations/black_rightarrow_df_4.ma".
-include "ground/xoa/ex_1_2.ma".
-include "ground/xoa/and_4.ma".
 
 (* DELAYED FOCUSED REDUCTION ************************************************)
 
 definition dfr (p) (q): relation2 prototerm prototerm ≝
-           λt1,t2. ∃∃b,n.
-           let r ≝ p●𝗔◗b●𝗟◗q in
-           ∧∧ (⊗b ϵ 𝐁 ∧ 𝟎 = ♭b) & ↑♭q = (▼[r]𝐢)@⧣❨n❩ & r◖𝗱n ϵ t1 &
-              t1[⋔r←𝛗(n+♭b).(t1⋔(p◖𝗦))] ⇔ t2
+           λt1,t2. ∃n:pnat.
+           let r ≝ p●𝗔◗𝗟◗q in
+           ∧∧ (𝗟◗q)ᴿ = ↳[n](rᴿ) & r◖𝗱n ϵ t1 &
+              t1[⋔r←𝛗n.(t1⋔(p◖𝗦))] ⇔ t2
 .
 
 interpretation