elim (lifts_inv_lref2 … HX) -HX #i1 #Hf #H destruct
lapply (drops_split_div … HL21 (𝐔❴i1❵) ???) -HL21 [4: * |*: // ] #Y #HLK1 #HY
lapply (drops_conf … HLK2 … HY ??) -HY [1,2: /2 width=6 by after_uni_dx/ ] #HY
lapply (drops_inv_tls_at … Hf … HY) -HY #HY -Hf
elim (drops_inv_skip1 … HY) -HY #K1 #V1 #HK21 #HV12 #H destruct
elim (lifts_inv_lref2 … HX) -HX #i1 #Hf #H destruct
lapply (drops_split_div … HL21 (𝐔❴i1❵) ???) -HL21 [4: * |*: // ] #Y #HLK1 #HY
lapply (drops_conf … HLK2 … HY ??) -HY [1,2: /2 width=6 by after_uni_dx/ ] #HY
lapply (drops_inv_tls_at … Hf … HY) -HY #HY -Hf
elim (drops_inv_skip1 … HY) -HY #K1 #V1 #HK21 #HV12 #H destruct