X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=matita%2Fmatita%2Fcontribs%2Flambdadelta%2Fbasic_2%2Fsubstitution%2Fcpye_lift.ma;h=1d494871ced9faa4362fb670d80cb57856aa6c88;hb=e2527c6784c2593ca67af35fafaf0b3725d80a60;hp=a14708dfc9e2de5b1884b5d2de10f982e123ce5f;hpb=09f9b390eb43b7dfddd4c8859a2ee7ac09a30aca;p=helm.git

diff --git a/matita/matita/contribs/lambdadelta/basic_2/substitution/cpye_lift.ma b/matita/matita/contribs/lambdadelta/basic_2/substitution/cpye_lift.ma
index a14708dfc..1d494871c 100644
--- a/matita/matita/contribs/lambdadelta/basic_2/substitution/cpye_lift.ma
+++ b/matita/matita/contribs/lambdadelta/basic_2/substitution/cpye_lift.ma
@@ -19,6 +19,8 @@ include "basic_2/substitution/cpye.ma".
 
 (* EVALUATION FOR CONTEXT-SENSITIVE EXTENDED SUBSTITUTION ON TERMS **********)
 
+(* Advanced properties ******************************************************)
+
 lemma cpye_subst: ∀I,G,L,K,V1,V2,W2,i,d,e. d ≤ yinj i → i < d + e →
                   ⇩[i] L ≡ K.ⓑ{I}V1 → ⦃G, K⦄ ⊢ V1 ▶*[O, ⫰(d+e-i)] 𝐍⦃V2⦄ →
                   ⇧[O, i+1] V2 ≡ W2 → ⦃G, L⦄ ⊢ #i ▶*[d, e] 𝐍⦃W2⦄.
@@ -46,3 +48,46 @@ lemma cpys_total: ∀G,L,T1,d,e. ∃T2. ⦃G, L⦄ ⊢ T1 ▶*[d, e] 𝐍⦃T2
   /3 width=2 by cpye_flat, ex_intro/
 ]
 qed-.
+
+(* Advanced inversion lemmas ************************************************)
+
+lemma cpye_inv_lref1: ∀G,L,T2,d,e,i. ⦃G, L⦄ ⊢ #i ▶*[d, e] 𝐍⦃T2⦄ →
+                      ∨∨ |L| ≤ i ∧ T2 = #i
+                       | d + e ≤ yinj i ∧ T2 = #i
+                       | yinj i < d ∧ T2 = #i
+                       | ∃∃I,K,V1,V2. d ≤ yinj i & yinj i < d + e &
+                                      ⇩[i] L ≡ K.ⓑ{I}V1 &
+                                      ⦃G, K⦄ ⊢ V1 ▶*[yinj 0, ⫰(d+e-yinj i)]  𝐍⦃V2⦄ &
+                                      ⇧[O, i+1] V2 ≡ T2.
+#G #L #T2 #i #d #e * #H1 #H2 elim (cpys_inv_lref1 … H1) -H1
+[ #H destruct elim (cny_inv_lref … H2) -H2
+  /3 width=1 by or4_intro0, or4_intro1, or4_intro2, conj/
+| * #I #K #V1 #V2 #Hdi #Hide #HLK #HV12 #HVT2
+    @or4_intro3 @(ex5_4_intro … HLK … HVT2) (**) (* explicit constructor *)
+    /4 width=13 by cny_inv_subst_aux, ldrop_fwd_drop2, conj/
+]
+qed-.
+
+lemma cpye_inv_lref1_free: ∀G,L,T2,d,e,i. ⦃G, L⦄ ⊢ #i ▶*[d, e] 𝐍⦃T2⦄ →
+                           (∨∨ |L| ≤ i | d + e ≤ yinj i | yinj i < d) → T2 = #i.
+#G #L #T2 #d #e #i #H * elim (cpye_inv_lref1 … H) -H * //
+#I #K #V1 #V2 #Hdi #Hide #HLK #_ #_ #H
+[ elim (lt_refl_false i) -d
+  @(lt_to_le_to_lt … H) -H /2 width=5 by ldrop_fwd_length_lt2/ (**) (* full auto slow: 19s *)
+]
+elim (ylt_yle_false … H) //
+qed-.
+
+lemma cpye_inv_lref1_subst: ∀G,L,T2,d,e,i. ⦃G, L⦄ ⊢ #i ▶*[d, e] 𝐍⦃T2⦄ →
+                            ∀I,K,V1,V2. d ≤ yinj i → yinj i < d + e →
+                            ⇩[i] L ≡ K.ⓑ{I}V1 → ⇧[O, i+1] V2 ≡ T2 →
+                            ⦃G, K⦄ ⊢ V1 ▶*[yinj 0, ⫰(d+e-yinj i)]  𝐍⦃V2⦄.
+#G #L #T2 #d #e #i #H #I #K #V1 #V2 #Hdi #Hide #HLK #HVT2 elim (cpye_inv_lref1 … H) -H *
+[ #H elim (lt_refl_false i) -V2 -T2 -d
+  @(lt_to_le_to_lt … H) -H /2 width=5 by ldrop_fwd_length_lt2/
+|2,3: #H elim (ylt_yle_false … H) //
+| #Z #Y #X1 #X2 #_ #_ #HLY #HX12 #HXT2
+  lapply (ldrop_mono … HLY … HLK) -HLY -HLK #H destruct
+  lapply (lift_inj … HXT2 … HVT2) -HXT2 -HVT2 #H destruct //
+]
+qed-.