| snv_lref: ∀I,L,K,V,i. ⇩[0, i] L ≡ K.ⓑ{I}V → snv h g K V → snv h g L (#i)
| snv_bind: ∀a,I,L,V,T. snv h g L V → snv h g (L.ⓑ{I}V) T → snv h g L (ⓑ{a,I}V.T)
| snv_appl: ∀a,L,V,W,W0,T,U,l. snv h g L V → snv h g L T →
- ⦃h, L⦄ ⊢ V •[g, l + 1] W → L ⊢ W ➡* W0 →
+ ⦃h, L⦄ ⊢ V •[g] ⦃l+1, W⦄ → L ⊢ W ➡* W0 →
⦃h, L⦄ ⊢ T •*➡*[g] ⓛ{a}W0.U → snv h g L (ⓐV.T)
| snv_cast: ∀L,W,T,U,l. snv h g L W → snv h g L T →
- ⦃h, L⦄ ⊢ T •[g, l + 1] U → L ⊢ U ⬌* W → snv h g L (ⓝW.T)
+ ⦃h, L⦄ ⊢ T •[g] ⦃l+1, U⦄ → L ⊢ U ⬌* W → snv h g L (ⓝW.T)
.
interpretation "stratified native validity (term)"
fact snv_inv_appl_aux: ∀h,g,L,X. ⦃h, L⦄ ⊩ X :[g] → ∀V,T. X = ⓐV.T →
∃∃a,W,W0,U,l. ⦃h, L⦄ ⊩ V :[g] & ⦃h, L⦄ ⊩ T :[g] &
- ⦃h, L⦄ ⊢ V •[g, l + 1] W & L ⊢ W ➡* W0 &
+ ⦃h, L⦄ ⊢ V •[g] ⦃l+1, W⦄ & L ⊢ W ➡* W0 &
⦃h, L⦄ ⊢ T •*➡*[g] ⓛ{a}W0.U.
#h #g #L #X * -L -X
[ #L #k #V #T #H destruct
lemma snv_inv_appl: ∀h,g,L,V,T. ⦃h, L⦄ ⊩ ⓐV.T :[g] →
∃∃a,W,W0,U,l. ⦃h, L⦄ ⊩ V :[g] & ⦃h, L⦄ ⊩ T :[g] &
- ⦃h, L⦄ ⊢ V •[g, l + 1] W & L ⊢ W ➡* W0 &
+ ⦃h, L⦄ ⊢ V •[g] ⦃l+1, W⦄ & L ⊢ W ➡* W0 &
⦃h, L⦄ ⊢ T •*➡*[g] ⓛ{a}W0.U.
/2 width=3/ qed-.
fact snv_inv_cast_aux: ∀h,g,L,X. ⦃h, L⦄ ⊩ X :[g] → ∀W,T. X = ⓝW.T →
∃∃U,l. ⦃h, L⦄ ⊩ W :[g] & ⦃h, L⦄ ⊩ T :[g] &
- ⦃h, L⦄ ⊢ T •[g, l + 1] U & L ⊢ U ⬌* W.
+ ⦃h, L⦄ ⊢ T •[g] ⦃l+1, U⦄ & L ⊢ U ⬌* W.
#h #g #L #X * -L -X
[ #L #k #W #T #H destruct
| #I #L #K #V #i #_ #_ #W #T #H destruct
lemma snv_inv_cast: ∀h,g,L,W,T. ⦃h, L⦄ ⊩ ⓝW.T :[g] →
∃∃U,l. ⦃h, L⦄ ⊩ W :[g] & ⦃h, L⦄ ⊩ T :[g] &
- ⦃h, L⦄ ⊢ T •[g, l + 1] U & L ⊢ U ⬌* W.
+ ⦃h, L⦄ ⊢ T •[g] ⦃l+1, U⦄ & L ⊢ U ⬌* W.
/2 width=3/ qed-.
(* Basic forward lemmas *****************************************************)
-lemma snv_fwd_ssta: ∀h,g,L,T. ⦃h, L⦄ ⊩ T :[g] → ∃∃U,l. ⦃h, L⦄ ⊢ T •[g, l] U.
+lemma snv_fwd_ssta: ∀h,g,L,T. ⦃h, L⦄ ⊩ T :[g] → ∃∃l,U. ⦃h, L⦄ ⊢ T •[g] ⦃l, U⦄.
#h #g #L #T #H elim H -L -T
[ #L #k elim (deg_total h g k) /3 width=3/
-| * #L #K #V #i #HLK #_ * #W #l0 #HVW
+| * #L #K #V #i #HLK #_ * #l0 #W #HVW
[ elim (lift_total W 0 (i+1)) /3 width=8/
| elim (lift_total V 0 (i+1)) /3 width=8/
]