-lemma fqus_drops: â\88\80b,G,L,K,T,U,i. â¬\87*[i] L â\89\98 K â\86\92 â¬\86*[i] T ≘ U →
+lemma fqus_drops: â\88\80b,G,L,K,T,U,i. â\87©*[i] L â\89\98 K â\86\92 â\87§*[i] T ≘ U →
⦃G,L,U⦄ ⬂*[b] ⦃G,K,T⦄.
#b #G #L #K #T #U * /3 width=3 by fqup_drops_succ, fqup_fqus/
#HLK #HTU <(lifts_fwd_isid … HTU) -U // <(drops_fwd_isid … HLK) -K //
⦃G,L,U⦄ ⬂*[b] ⦃G,K,T⦄.
#b #G #L #K #T #U * /3 width=3 by fqup_drops_succ, fqup_fqus/
#HLK #HTU <(lifts_fwd_isid … HTU) -U // <(drops_fwd_isid … HLK) -K //