]> matita.cs.unibo.it Git - helm.git/blobdiff - matita/matita/contribs/lambdadelta/basic_2/relocation/lifts.ma
- advances towards strong normalization
[helm.git] / matita / matita / contribs / lambdadelta / basic_2 / relocation / lifts.ma
index d7176d732ac91d30bcfd8d3e1a9a6f654fb02679..31f416f12fcec83c6a36b10efd450b9cbf25580c 100644 (file)
@@ -15,7 +15,7 @@
 
 include "ground_2/relocation/nstream_after.ma".
 include "basic_2/notation/relations/rliftstar_3.ma".
-include "basic_2/grammar/term.ma".
+include "basic_2/syntax/term.ma".
 
 (* GENERIC RELOCATION FOR TERMS *********************************************)
 
@@ -41,6 +41,21 @@ interpretation "uniform relocation (term)"
 interpretation "generic relocation (term)"
    'RLiftStar f T1 T2 = (lifts f T1 T2).
 
+definition liftable2_sn: predicate (relation term) ≝
+                         λR. ∀T1,T2. R T1 T2 → ∀f,U1. ⬆*[f] T1 ≡ U1 → 
+                         ∃∃U2. ⬆*[f] T2 ≡ U2 & R U1 U2.
+
+definition deliftable2_sn: predicate (relation term) ≝
+                           λR. ∀U1,U2. R U1 U2 → ∀f,T1. ⬆*[f] T1 ≡ U1 →
+                           ∃∃T2. ⬆*[f] T2 ≡ U2 & R T1 T2.
+
+definition liftable2_bi: predicate (relation term) ≝
+                         λR. ∀T1,T2. R T1 T2 → ∀f,U1. ⬆*[f] T1 ≡ U1 → 
+                         ∀U2. ⬆*[f] T2 ≡ U2 → R U1 U2.
+
+definition deliftable2_bi: predicate (relation term) ≝
+                           λR. ∀U1,U2. R U1 U2 → ∀f,T1. ⬆*[f] T1 ≡ U1 →
+                           ∀T2. ⬆*[f] T2 ≡ U2 → R T1 T2.
 
 (* Basic inversion lemmas ***************************************************)