∀ {M : Type u_1} [inst : Mul M] {c d : Con M},
  { toFun := Con.op, invFun := Con.unop, left_inv := ⋯, right_inv := ⋯ } c ≤
      { toFun := Con.op, invFun := Con.unop, left_inv := ⋯, right_inv := ⋯ } d ↔
    c ≤ d