∀ {α : Type u} {r : Std.Ric α} [inst : LE α] [inst_1 : Std.PRange.Least? α] [inst_2 : Std.PRange.UpwardEnumerable α]
  [Std.PRange.LawfulUpwardEnumerable α] [Std.PRange.LawfulUpwardEnumerableLE α]
  [inst_5 : Std.PRange.LawfulUpwardEnumerableLeast? α] [Std.Rxc.IsAlwaysFinite α] {a : α},
  (a ∈ r) = (a ∈ Std.PRange.UpwardEnumerable.least...=r.upper)