[ #I #G #L #V1 #V2 #HV12 #_ elim (lift_total V2 0 1)
#U2 #HVU2 @(ex3_intro … U2)
[1,3: /3 width=7 by fqu_drop, cpxs_delta, drop_pair, drop_drop/
- | #H destruct /2 width=7 by lift_inv_lref2_be/
+ | #H destruct
+ lapply (lift_inv_lref2_be … HVU2 ? ?) -HVU2 //
]
| #I #G #L #V1 #T #V2 #HV12 #H @(ex3_intro … (②{I}V2.T))
[1,3: /2 width=4 by fqu_pair_sn, cpxs_pair_sn/