(* Basic_2A1: uses: lsx_lpx_trans *)
lemma rsx_lpx_trans (G):
∀L1,T. G ⊢ ⬈*𝐒[T] L1 →
- â\88\80L2. â\9dªG,L1â\9d« ⊢ ⬈ L2 → G ⊢ ⬈*𝐒[T] L2.
+ â\88\80L2. â\9d¨G,L1â\9d© ⊢ ⬈ L2 → G ⊢ ⬈*𝐒[T] L2.
#G #L1 #T #H @(rsx_ind … H) -L1 #L1 #HL1 #IHL1 #L2 #HL12
elim (reqx_dec … L1 L2 T) /3 width=4 by rsx_reqx_trans/
qed-.