∀ {α : Type u_1} {m : MeasurableSpace α} {s : MeasureTheory.SignedMeasure α} {μ : MeasureTheory.Measure α},
  s.toJordanDecomposition.posPart.HaveLebesgueDecomposition μ →
    s.toJordanDecomposition.negPart.HaveLebesgueDecomposition μ → s.HaveLebesgueDecomposition μ