no goals
α : Type u_1
β : Type ?u.338998
γ : Type ?u.339001
δ : Type ?u.339004
ι : Type u_2
R : Type ?u.339010
R' : Type ?u.339013
m0 : MeasurableSpace α
inst✝¹ : MeasurableSpace β
inst✝ : MeasurableSpace γ
μ✝ μ₁ μ₂ μ₃ ν ν' ν₁ ν₂ : Measure α
s✝ s' t : Set α
μ : ι → Measure α
s : Set α
hs : MeasurableSet s
⊢ ↑↑(sum μ) s = 0 ↔ ∀ (i : ι), ↑↑(μ i) s = 0
simp [hs]