(* *)
(**************************************************************************)
+include "delayed_updating/unwind1/unwind_prototerm.ma".
include "delayed_updating/substitution/fsubst.ma".
include "delayed_updating/substitution/lift_prototerm.ma".
+include "delayed_updating/syntax/prototerm_equivalence.ma".
include "delayed_updating/syntax/path_depth.ma".
include "delayed_updating/syntax/path_structure.ma".
include "delayed_updating/syntax/path_balanced.ma".
definition ifr (p) (q): relation2 prototerm prototerm ≝
λt1,t2. ∃∃b,n.
let r ≝ p●𝗔◗b●𝗟◗q in
- ∧∧ ⊗b ϵ 𝐁 & ∀f. ❘q❘ = (↑[q]⫯f)@❨n❩ & r◖𝗱n ϵ t1 &
- t1[⋔r←↑[𝐮❨n❩](t1⋔(p◖𝗦))] ⇔ t2
+ ∧∧ (⊗b ϵ 𝐁 ∧ 𝟎 = ♭b) & ↑♭q = (▼[r]𝐢)@❨n❩ & r◖𝗱n ϵ t1 &
+ t1[⋔r←↑[𝐮❨♭(b●𝗟◗q)❩](t1⋔(p◖𝗦))] ⇔ t2
.
interpretation