lapply (ltpssa_ltpss_sn … HL1) -HL1 #HL1
lapply (ltpss_sn_dx_trans_eq … HL1 … HL2) -HL1 #HL12
elim (IHL1 … H1) -IHL1 -H1 #U #HU1 #HTU
-elim (sstas_ltpss_dx_conf … HTU … HL2) -HTU -HL2 #U2 #H2 #HU2
+elim (sstas_ltpss_dx_conf … HTU … HL2) -HTU -HL2 #U2 #H2 #HU2
lapply (ltpss_sn_tpss_trans_eq … HU2 … HL12) -HU2 -HL12 #HU2
lapply (tpss_trans_eq … HU1 HU2) -U /2 width=3/
qed.