qed.
lemma rsx_unit (G): ∀I,L. G ⊢ ⬈*𝐒[#0] L.ⓤ[I].
#G #I #L1 @rsx_intro
#Y #HY #HnY elim HnY -HnY
elim (lpx_inv_unit_sn … HY) -HY #L2 #HL12 #H destruct
qed.
lemma rsx_unit (G): ∀I,L. G ⊢ ⬈*𝐒[#0] L.ⓤ[I].
#G #I #L1 @rsx_intro
#Y #HY #HnY elim HnY -HnY
elim (lpx_inv_unit_sn … HY) -HY #L2 #HL12 #H destruct