1 (**************************************************************************)
4 (* ||A|| A project by Andrea Asperti *)
6 (* ||I|| Developers: *)
7 (* ||T|| The HELM team. *)
8 (* ||A|| http://helm.cs.unibo.it *)
10 (* \ / This file is distributed under the terms of the *)
11 (* v GNU General Public License Version 2 *)
13 (**************************************************************************)
15 include "basic_2/static/da_aaa.ma".
16 include "basic_2/computation/scpds_aaa.ma".
17 include "basic_2/dynamic/snv.ma".
19 (* STRATIFIED NATIVE VALIDITY FOR TERMS *************************************)
21 (* Advanced forward lemmas **************************************************)
23 lemma snv_fwd_da: ∀h,o,G,L,T. ⦃G, L⦄ ⊢ T ¡[h, o] → ∃d. ⦃G, L⦄ ⊢ T ▪[h, o] d.
24 #h #o #G #L #T #H elim (snv_fwd_aaa … H) -H /2 width=2 by aaa_da/
27 lemma snv_fwd_lstas: ∀h,o,G,L,T. ⦃G, L⦄ ⊢ T ¡[h, o] →
28 ∀d. ∃U. ⦃G, L⦄ ⊢ T •*[h, d] U.
29 #h #o #G #L #T #H #d elim (snv_fwd_aaa … H) -H
30 #A #HT elim (aaa_lstas h … HT d) -HT /2 width=2 by ex_intro/