(* Properties with generic slicing for local environments *******************)
lemma fqus_drops: ∀b,G,L,K,T,U,i. ⇩*[i] L ≘ K → ⇧*[i] T ≘ U →
- â¦\83G,L,Uâ¦\84 â¬\82*[b] â¦\83G,K,Tâ¦\84.
+ â\9dªG,L,Uâ\9d« â¬\82*[b] â\9dªG,K,Tâ\9d«.
#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 //
qed.