X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=matita%2Fmatita%2Fcontribs%2Flambdadelta%2Fbasic_2%2Frelocation%2Flift.ma;h=e72288dffbedbcba96dec91c036aa116b11e47ca;hb=ef49e0e7f5f298c299afdd3cbfdc2404ecb93879;hp=da4dd9c5acfa71ccd81206f989718917fd00265c;hpb=ae78107140dc0d87bfb4db6d8d9861c4796df6d7;p=helm.git

diff --git a/matita/matita/contribs/lambdadelta/basic_2/relocation/lift.ma b/matita/matita/contribs/lambdadelta/basic_2/relocation/lift.ma
index da4dd9c5a..e72288dff 100644
--- a/matita/matita/contribs/lambdadelta/basic_2/relocation/lift.ma
+++ b/matita/matita/contribs/lambdadelta/basic_2/relocation/lift.ma
@@ -268,6 +268,22 @@ qed-.
 
 (* Basic forward lemmas *****************************************************)
 
+lemma lift_fwd_pair1: ∀I,T2,V1,U1,d,e. ⇧[d,e] ②{I}V1.U1 ≡ T2 →
+                      ∃∃V2,U2. ⇧[d,e] V1 ≡ V2 & T2 = ②{I}V2.U2.
+* [ #a ] #I #T2 #V1 #U1 #d #e #H
+[ elim (lift_inv_bind1 … H) -H /2 width=4/
+|  elim (lift_inv_flat1 … H) -H /2 width=4/
+] 
+qed-.
+
+lemma lift_fwd_pair2: ∀I,T1,V2,U2,d,e. ⇧[d,e] T1 ≡ ②{I}V2.U2 →
+                      ∃∃V1,U1. ⇧[d,e] V1 ≡ V2 & T1 = ②{I}V1.U1.
+* [ #a ] #I #T1 #V2 #U2 #d #e #H
+[ elim (lift_inv_bind2 … H) -H /2 width=4/
+|  elim (lift_inv_flat2 … H) -H /2 width=4/
+] 
+qed-.
+
 lemma lift_fwd_tw: ∀d,e,T1,T2. ⇧[d, e] T1 ≡ T2 → ♯{T1} = ♯{T2}.
 #d #e #T1 #T2 #H elim H -d -e -T1 -T2 normalize //
 qed-.