(* Inversion lemmas on negated lazy quivalence for local environments *******)
lemma nlleq_inv_bind: ∀a,I,L1,L2,V,T,l. (L1 ≡[ⓑ{a,I}V.T, l] L2 → ⊥) →
- (L1 â\89¡[V, l] L2 â\86\92 â\8a¥) â\88¨ (L1.â\93\91{I}V â\89¡[T, ⫯l] L2.ⓑ{I}V → ⊥).
+ (L1 â\89¡[V, l] L2 â\86\92 â\8a¥) â\88¨ (L1.â\93\91{I}V â\89¡[T, â\86\91l] L2.ⓑ{I}V → ⊥).
/3 width=2 by nllpx_sn_inv_bind, eq_term_dec/ qed-.
lemma nlleq_inv_flat: ∀I,L1,L2,V,T,l. (L1 ≡[ⓕ{I}V.T, l] L2 → ⊥) →