- lambdadelta: more service lemmas ...

[helm.git] / matita / matita / contribs / lambdadelta / basic_2 / equivalence / fpcs_cpcs.ma

diff --git a/matita/matita/contribs/lambdadelta/basic_2/equivalence/fpcs_cpcs.ma b/matita/matita/contribs/lambdadelta/basic_2/equivalence/fpcs_cpcs.ma
index 4b51a7084a689e03eede15639a0a1bf110f82579..eda395e98bb78b431ca2bc50392d67b63c6bbf86 100644 (file)
--- a/matita/matita/contribs/lambdadelta/basic_2/equivalence/fpcs_cpcs.ma
+++ b/matita/matita/contribs/lambdadelta/basic_2/equivalence/fpcs_cpcs.ma
@@ -14,13 +14,42 @@
 
 include "basic_2/computation/fprs_cprs.ma".
 include "basic_2/equivalence/cpcs_cpcs.ma".
-include "basic_2/equivalence/fpcs_fprs.ma".
+include "basic_2/equivalence/fpcs_fpcs.ma".
 
 (* CONTEXT-FREE PARALLEL EQUIVALENCE ON CLOSURES ****************************)
 
+(* Advanced properties ******************************************************)
+
+lemma fpcs_shift: ∀I,L1,L2,V1,V2,T1,T2. ⦃L1.ⓑ{I}V1, T1⦄ ⬌* ⦃L2.ⓑ{I}V2, T2⦄ →
+                     ⦃L1, -ⓑ{I}V1.T1⦄ ⬌* ⦃L2, -ⓑ{I}V2.T2⦄.
+#I #L1 #L2 #V1 #V2 #T1 #T2 #H12
+elim (fpcs_inv_fprs … H12) -H12 #L #T #H1 #H2
+elim (fprs_inv_pair1 … H1) -H1 #K1 #U1 #_ #HTU1 #H destruct
+elim (fprs_inv_pair1 … H2) -H2 #K2 #U2 #_ #HTU2 #H destruct /2 width=4/
+qed.
+
+lemma fpcs_bind_minus: ∀I,L1,L2,V1,V2,T1,T2. ⦃L1, -ⓑ{I}V1.T1⦄ ⬌* ⦃L2, -ⓑ{I}V2.T2⦄ →
+                       ∀b. ⦃L1, ⓑ{b,I}V1.T1⦄ ⬌* ⦃L2, ⓑ{b,I}V2.T2⦄.
+#I #L1 #L2 #V1 #V2 #T1 #T2 #H12 #b
+elim (fpcs_inv_fprs … H12) -H12 #L #T #H1 #H2
+elim (fprs_fwd_bind2_minus … H1 b) -H1 #W1 #U1 #HTU1 #H destruct
+elim (fprs_fwd_bind2_minus … H2 b) -H2 #W2 #U2 #HTU2 #H destruct /2 width=4/
+qed.
+
+lemma fpcs_shift_full: ∀I,L1,L2,V1,V2,T1,T2. ⦃L1.ⓑ{I}V1, T1⦄ ⬌* ⦃L2.ⓑ{I}V2, T2⦄ →
+                       ∀b. ⦃L1, ⓑ{b,I}V1.T1⦄ ⬌* ⦃L2, ⓑ{b,I}V2.T2⦄.
+/3 width=1/ qed.
+
 (* Properties on context-sensitive parallel equivalence for terms ***********)
 
 lemma cpcs_fpcs: ∀L,T1,T2. L ⊢ T1 ⬌* T2 → ⦃L, T1⦄ ⬌* ⦃L, T2⦄.
 #L #T1 #T2 #H
 elim (cpcs_inv_cprs … H) -H /3 width=4 by fprs_div, cprs_fprs/ (**) (* too slow without trace *)
 qed.
+
+(* Inversion lemmas on context-sensitive parallel equivalence for terms *****)
+
+lemma fpcs_inv_cpcs: ∀L,T1,T2. ⦃L, T1⦄ ⬌* ⦃L, T2⦄ → L ⊢ T1 ⬌* T2.
+#L #T1 #T2 #H
+elim (fpcs_inv_fprs … H) -H /3 width=4 by cprs_div, fprs_fwd_cprs/
+qed-.