(* *)
(**************************************************************************)
+include "ground_2/xoa/ex_5_3.ma".
include "basic_2/rt_equivalence/cpcs_cpcs.ma".
include "basic_2/dynamic/cnv_preserve_cpcs.ma".
include "basic_2/dynamic/nta.ma".
]
qed-.
-lemma nta_inv_lref_sn_drops_cnv (h) (a) (G) (L):
+lemma nta_inv_lref_sn_drops_cnv (h) (a) (G) (L):
∀X2,i. ⦃G,L⦄ ⊢ #i :[h,a] X2 →
∨∨ ∃∃K,V,W,U. ⇩*[i] L ≘ K.ⓓV & ⦃G,K⦄ ⊢ V :[h,a] W & ⇧*[↑i] W ≘ U & ⦃G,L⦄ ⊢ U ⬌*[h] X2 & ⦃G,L⦄ ⊢ X2 ![h,a]
| ∃∃K,W,U. ⇩*[i] L ≘ K. ⓛW & ⦃G,K⦄ ⊢ W ![h,a] & ⇧*[↑i] W ≘ U & ⦃G,L⦄ ⊢ U ⬌*[h] X2 & ⦃G,L⦄ ⊢ X2 ![h,a].