+
+(* Advanced forward lemmas **************************************************)
+
+fact csx_fwd_bind_dx_unit_aux (h) (G):
+ ∀L,U. ⦃G,L⦄ ⊢ ⬈*[h] 𝐒⦃U⦄ →
+ ∀p,I,J,V,T. U = ⓑ{p,I}V.T → ⦃G,L.ⓤ{J}⦄ ⊢ ⬈*[h] 𝐒⦃T⦄.
+#h #G #L #U #H elim H -H #U0 #_ #IH #p #I #J #V #T #H destruct
+@csx_intro #T2 #HLT2 #HT2
+@(IH (ⓑ{p, I}V.T2)) -IH /2 width=4 by cpx_bind_unit/ -HLT2
+#H elim (tdeq_inv_pair … H) -H /2 width=1 by/
+qed-.
+
+lemma csx_fwd_bind_dx_unit (h) (G):
+ ∀p,I,L,V,T. ⦃G,L⦄ ⊢ ⬈*[h] 𝐒⦃ⓑ{p,I}V.T⦄ →
+ ∀J. ⦃G,L.ⓤ{J}⦄ ⊢ ⬈*[h] 𝐒⦃T⦄.
+/2 width=6 by csx_fwd_bind_dx_unit_aux/ qed-.
+
+lemma csx_fwd_bind_unit (h) (G):
+ ∀p,I,L,V,T. ⦃G,L⦄ ⊢ ⬈*[h] 𝐒⦃ⓑ{p,I}V.T⦄ →
+ ∀J. ⦃G,L⦄ ⊢ ⬈*[h] 𝐒⦃V⦄ ∧ ⦃G,L.ⓤ{J}⦄ ⊢ ⬈*[h] 𝐒⦃T⦄.
+/3 width=4 by csx_fwd_pair_sn, csx_fwd_bind_dx_unit, conj/ qed-.
+
+(* Properties with restricted refinement for local environments *************)
+
+lemma csx_lsubr_conf (h) (G):
+ ∀L1,T. ⦃G,L1⦄ ⊢ ⬈*[h] 𝐒⦃T⦄ → ∀L2. L1 ⫃ L2 → ⦃G,L2⦄ ⊢ ⬈*[h] 𝐒⦃T⦄.
+#h #G #L1 #T #H
+@(csx_ind … H) -T #T1 #_ #IH #L2 #HL12
+@csx_intro #T2 #HT12 #HnT12
+/3 width=3 by lsubr_cpx_trans/
+qed-.