∀ {α : Type u_1} {ι : Type u_5} {m0 : MeasurableSpace α} [Countable ι] {μ : ι → MeasureTheory.Measure α} {p : α → Prop},
  (∀ᵐ (x : α) ∂MeasureTheory.Measure.sum μ, p x) ↔ ∀ (i : ι), ∀ᵐ (x : α) ∂μ i, p x