- advances on hereditarily free variables: now "frees" is primitive

[helm.git] / matita / matita / contribs / lambdadelta / basic_2 / relocation / lift_neg.ma

diff --git a/matita/matita/contribs/lambdadelta/basic_2/relocation/lift_neg.ma b/matita/matita/contribs/lambdadelta/basic_2/relocation/lift_neg.ma
index 220748ed318ee8ec98b391a7b9540c1baf37571a..6f4dd68d3c76279f8996e99d98e562ebf4e1846f 100644 (file)
--- a/matita/matita/contribs/lambdadelta/basic_2/relocation/lift_neg.ma
+++ b/matita/matita/contribs/lambdadelta/basic_2/relocation/lift_neg.ma
@@ -43,6 +43,13 @@ qed-.
 
 (* Inversion lemmas on negated basic relocation *****************************)
 
+lemma nlift_inv_lref_be_SO: ∀i,j. (∀X. ⇧[i, 1] X ≡ #j → ⊥) → j = i.
+#i #j elim (lt_or_eq_or_gt i j) // #Hij #H
+[ elim (H (#(j-1))) -H /2 width=1 by lift_lref_ge_minus/
+| elim (H (#j)) -H /2 width=1 by lift_lref_lt/
+]
+qed-.
+
 lemma nlift_inv_bind: ∀a,I,W,U,d,e. (∀X. ⇧[d, e] X ≡ ⓑ{a,I}W.U → ⊥) →
                       (∀V. ⇧[d, e] V ≡ W → ⊥) ∨ (∀T. ⇧[d+1, e] T ≡ U → ⊥).
 #a #I #W #U #d #e #H elim (is_lift_dec W d e)