∀ {A : Type u_4} [inst : NormedRing A] [inst_1 : NormedAlgebra ℝ A] [CompleteSpace A] {a : A},
  (spectrum ℝ a).Nonempty → SpectrumRestricts a ⇑ContinuousMap.realToNNReal → (spectralRadius ℝ a).toReal ∈ spectrum ℝ a