include "delayed_updating/syntax/path_balanced.ma".
include "delayed_updating/syntax/path_depth.ma".
include "delayed_updating/notation/relations/black_rightarrow_df_4.ma".
+include "ground/arith/nat_rplus.ma".
include "ground/xoa/ex_1_2.ma".
include "ground/xoa/and_4.ma".
definition dfr (p) (q): relation2 prototerm prototerm ≝
λt1,t2. ∃∃b,n.
let r ≝ p●𝗔◗b●𝗟◗q in
- â\88§â\88§ â\8a\97b ϵ ð\9d\90\81 & â\9d\98qâ\9d\98 = (â\86\91[q]ð\9d\90¢)@❨n❩ & r◖𝗱n ϵ t1 &
- t1[⋔r←𝛗n.(t1⋔(p◖𝗦))] ⇔ t2
+ â\88§â\88§ â\8a\97b ϵ ð\9d\90\81 & â\88\80f. â\86\91â\9d\98qâ\9d\98 = (â\86\91[q]⫯f)@❨n❩ & r◖𝗱n ϵ t1 &
+ t1[⋔r←𝛗(n+❘b❘).(t1⋔(p◖𝗦))] ⇔ t2
.
interpretation