diamond property of reduction!

[helm.git] / matita / matita / contribs / lambdadelta / basic_2 / rt_transition / lfpx_drops.ma

diff --git a/matita/matita/contribs/lambdadelta/basic_2/rt_transition/lfpx_drops.ma b/matita/matita/contribs/lambdadelta/basic_2/rt_transition/lfpx_drops.ma
index 55c4051628ca455bd10df0706428d3b9e475172e..086e71e87bd791fd522681adf3feb065a4419220 100644 (file)
--- a/matita/matita/contribs/lambdadelta/basic_2/rt_transition/lfpx_drops.ma
+++ b/matita/matita/contribs/lambdadelta/basic_2/rt_transition/lfpx_drops.ma
@@ -30,3 +30,11 @@ lemma lfpx_drops_conf: ∀h,G. dropable_sn (cpx h G).
 
 lemma lfpx_drops_trans: ∀h,G. dropable_dx (cpx h G).
 /2 width=5 by lfxs_dropable_dx/ qed-.
+
+lemma lfpx_inv_lref_sn: ∀h,G,L1,L2,i. ⦃G, L1⦄ ⊢ ⬈[h, #i] L2 → ∀I,K1,V1. ⬇*[i] L1 ≡ K1.ⓑ{I}V1 →
+                        ∃∃K2,V2. ⬇*[i] L2 ≡ K2.ⓑ{I}V2 & ⦃G, K1⦄ ⊢ ⬈[h, V1] K2 & ⦃G, K1⦄ ⊢ V1 ⬈[h] V2.
+/2 width=3 by lfxs_inv_lref_sn/ qed-.
+
+lemma lfpx_inv_lref_dx: ∀h,G,L1,L2,i. ⦃G, L1⦄ ⊢ ⬈[h, #i] L2 → ∀I,K2,V2. ⬇*[i] L2 ≡ K2.ⓑ{I}V2 →
+                        ∃∃K1,V1. ⬇*[i] L1 ≡ K1.ⓑ{I}V1 & ⦃G, K1⦄ ⊢ ⬈[h, V1] K2 & ⦃G, K1⦄ ⊢ V1 ⬈[h] V2.
+/2 width=3 by lfxs_inv_lref_dx/ qed-.