update in basic_2

[helm.git] / matita / matita / contribs / lambdadelta / basic_2 / etc / fpbg / fpbg_lift.etc

diff --git a/matita/matita/contribs/lambdadelta/basic_2/etc/fpbg/fpbg_lift.etc b/matita/matita/contribs/lambdadelta/basic_2/etc/fpbg/fpbg_lift.etc
index 4fe3be22f29b33c3a3895962605099231aeafffa..04110fe2129647f415d49fa3e6cf394b9ba11ff5 100644 (file)
--- a/matita/matita/contribs/lambdadelta/basic_2/etc/fpbg/fpbg_lift.etc
+++ b/matita/matita/contribs/lambdadelta/basic_2/etc/fpbg/fpbg_lift.etc
@@ -22,3 +22,7 @@ include "basic_2/computation/fpbg.ma".
 lemma sta_fpbg: ∀h,o,G,L,T1,T2,d. ⦃G, L⦄ ⊢ T1 ▪[h, o] d+1 →
                 ⦃G, L⦄ ⊢ T1 •*[h, 1] T2 → ⦃G, L, T1⦄ >≛[h, o] ⦃G, L, T2⦄.
 /4 width=2 by fpb_fpbg, sta_fpb/ qed.
+
+lemma lstas_fpbg: ∀h,o,G,L,T1,T2,d2. ⦃G, L⦄ ⊢ T1 •*[h, d2] T2 → (T1 = T2 → ⊥) →
+                  ∀d1. d2 ≤ d1 → ⦃G, L⦄ ⊢ T1 ▪[h, o] d1 → ⦃G, L, T1⦄ >≛[h, o] ⦃G, L, T2⦄.
+/3 width=5 by lstas_cpxs, cpxs_fpbg/ qed.