fact: Fixpoint hlist_erase {A B} {ls : list A} (hs : hlist (fun _ => B) ls) : list B := match hs with | Hnil => nil | Hcons _ _ x hs' => cons x (hlist_erase hs') end.
imports: Coq.Lists.List Coq.Arith.PeanoNat Relations RelationClasses ExtLib.Core.RelDec ExtLib.Data.SigT ExtLib.Data.Member ExtLib.Data.ListNth ExtLib.Data.Option ExtLib.Tactics Coq.Classes.Morphisms