#T1 #_ #IH #b #f #L #HLK #U1 #HTU1
@csx_intro #U2 #HU12 #HnU12
elim (cpx_inv_lifts_sn … HU12 … HLK … HTU1) -HU12
#T1 #_ #IH #b #f #L #HLK #U1 #HTU1
@csx_intro #U2 #HU12 #HnU12
elim (cpx_inv_lifts_sn … HU12 … HLK … HTU1) -HU12
#U1 #_ #IH #b #f #K #HLK #T1 #HTU1
@csx_intro #T2 #HT12 #HnT12
elim (cpx_lifts_sn … HT12 … HLK … HTU1) -HT12
#U1 #_ #IH #b #f #K #HLK #T1 #HTU1
@csx_intro #T2 #HT12 #HnT12
elim (cpx_lifts_sn … HT12 … HLK … HTU1) -HT12