| 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 →
| 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 →