∀ {M : Type u_1} [inst : AddCommGroup M] [inst_1 : LinearOrder M] [inst_2 : IsOrderedAddMonoid M] (K : Type u_2)
  [inst_3 : Ring K] [inst_4 : LinearOrder K] [inst_5 : IsOrderedRing K] [inst_6 : Archimedean K] [inst_7 : Module K M]
  [inst_8 : PosSMulMono K M] {a : M} {c : ArchimedeanClass M},
  (a ∈ ArchimedeanClass.closedBall K c) = (c ≤ ArchimedeanClass.mk a)