lfsx_drops completed

[helm.git] / matita / matita / contribs / lambdadelta / basic_2 / rt_computation / csx_csx.ma

diff --git a/matita/matita/contribs/lambdadelta/basic_2/rt_computation/csx_csx.ma b/matita/matita/contribs/lambdadelta/basic_2/rt_computation/csx_csx.ma
index a0f48f82897dd64e094a1a961b860c900b409b15..69ca48513c4d5ed6b008038b17d156388363f76a 100644 (file)
--- a/matita/matita/contribs/lambdadelta/basic_2/rt_computation/csx_csx.ma
+++ b/matita/matita/contribs/lambdadelta/basic_2/rt_computation/csx_csx.ma
@@ -73,3 +73,11 @@ lemma csx_inv_lref_pair: ∀h,o,I,G,L,K,V,i. ⬇*[i] L ≡ K.ⓑ{I}V →
 elim (lifts_total V (𝐔❴⫯i❵))
 /4 width=9 by csx_inv_lifts, csx_cpx_trans, cpx_delta_drops, drops_isuni_fwd_drop2/
 qed-.
+
+lemma csx_inv_lref: ∀h,o,G,L,i. ⦃G, L⦄ ⊢ ⬈*[h, o] 𝐒⦃#i⦄ →
+                    ∨∨ ⬇*[Ⓕ, 𝐔❴i❵] L ≡ ⋆
+                     | ∃∃I,K. ⬇*[i] L ≡ K.ⓤ{I}
+                     | ∃∃I,K,V. ⬇*[i] L ≡ K.ⓑ{I}V & ⦃G, K⦄ ⊢ ⬈*[h, o] 𝐒⦃V⦄.
+#h #o #G #L #i #H elim (drops_F_uni L i) /2 width=1 by or3_intro0/
+* * /4 width=9 by csx_inv_lref_pair, ex2_3_intro, ex1_2_intro, or3_intro2, or3_intro1/
+qed-.