Module: Mathlib.MeasureTheory.VectorMeasure.Decomposition.Jordan

Goal state before:
pp: α : Type u_1
inst✝ : MeasurableSpace α
j₁ j₂ : JordanDecomposition α
hj : j₁.toSignedMeasure = j₂.toSignedMeasure
S : Set α
hS₁ : MeasurableSet S
hS₂ : j₁.toSignedMeasure ≤[S] 0
hS₃ : 0 ≤[Sᶜ] j₁.toSignedMeasure
hS₄ : j₁.posPart S = 0
hS₅ : j₁.negPart Sᶜ = 0
T : Set α
hT₁ : MeasurableSet T
hT₂ : j₁.toSignedMeasure ≤[T] 0
hT₃ : 0 ≤[Tᶜ] j₁.toSignedMeasure
hT₄ : j₂.posPart T = 0
hT₅ : j₂.negPart Tᶜ = 0
hST₁ : j₁.toSignedMeasure (symmDiff Sᶜ Tᶜ) = 0
i : Set α
hi : MeasurableSet i
⊢ (j₁.posPart (i ∩ S)).toReal + j₁.posPart.real (i ∩ Sᶜ) = j₁.posPart.real (i ∩ Sᶜ)

pp: case hd
α : Type u_1
inst✝ : MeasurableSpace α
j₁ j₂ : JordanDecomposition α
hj : j₁.toSignedMeasure = j₂.toSignedMeasure
S : Set α
hS₁ : MeasurableSet S
hS₂ : j₁.toSignedMeasure ≤[S] 0
hS₃ : 0 ≤[Sᶜ] j₁.toSignedMeasure
hS₄ : j₁.posPart S = 0
hS₅ : j₁.negPart Sᶜ = 0
T : Set α
hT₁ : MeasurableSet T
hT₂ : j₁.toSignedMeasure ≤[T] 0
hT₃ : 0 ≤[Tᶜ] j₁.toSignedMeasure
hT₄ : j₂.posPart T = 0
hT₅ : j₂.negPart Tᶜ = 0
hST₁ : j₁.toSignedMeasure (symmDiff Sᶜ Tᶜ) = 0
i : Set α
hi : MeasurableSet i
⊢ Disjoint (i ∩ S) (i ∩ Sᶜ)

pp: case h
α : Type u_1
inst✝ : MeasurableSpace α
j₁ j₂ : JordanDecomposition α
hj : j₁.toSignedMeasure = j₂.toSignedMeasure
S : Set α
hS₁ : MeasurableSet S
hS₂ : j₁.toSignedMeasure ≤[S] 0
hS₃ : 0 ≤[Sᶜ] j₁.toSignedMeasure
hS₄ : j₁.posPart S = 0
hS₅ : j₁.negPart Sᶜ = 0
T : Set α
hT₁ : MeasurableSet T
hT₂ : j₁.toSignedMeasure ≤[T] 0
hT₃ : 0 ≤[Tᶜ] j₁.toSignedMeasure
hT₄ : j₂.posPart T = 0
hT₅ : j₂.negPart Tᶜ = 0
hST₁ : j₁.toSignedMeasure (symmDiff Sᶜ Tᶜ) = 0
i : Set α
hi : MeasurableSet i
⊢ MeasurableSet (i ∩ Sᶜ)

Tactic:
show j₁.posPart (i ∩ S) = 0 from
        nonpos_iff_eq_zero.1 (hS₄ ▸ measure_mono Set.inter_subset_right),

Goal state after:
α : Type u_1
inst✝ : MeasurableSpace α
j₁ j₂ : JordanDecomposition α
hj : j₁.toSignedMeasure = j₂.toSignedMeasure
S : Set α
hS₁ : MeasurableSet S
hS₂ : j₁.toSignedMeasure ≤[S] 0
hS₃ : 0 ≤[Sᶜ] j₁.toSignedMeasure
hS₄ : j₁.posPart S = 0
hS₅ : j₁.negPart Sᶜ = 0
T : Set α
hT₁ : MeasurableSet T
hT₂ : j₁.toSignedMeasure ≤[T] 0
hT₃ : 0 ≤[Tᶜ] j₁.toSignedMeasure
hT₄ : j₂.posPart T = 0
hT₅ : j₂.negPart Tᶜ = 0
hST₁ : j₁.toSignedMeasure (symmDiff Sᶜ Tᶜ) = 0
i : Set α
hi : MeasurableSet i
⊢ ENNReal.toReal 0 + j₁.posPart.real (i ∩ Sᶜ) = j₁.posPart.real (i ∩ Sᶜ)

case hd
α : Type u_1
inst✝ : MeasurableSpace α
j₁ j₂ : JordanDecomposition α
hj : j₁.toSignedMeasure = j₂.toSignedMeasure
S : Set α
hS₁ : MeasurableSet S
hS₂ : j₁.toSignedMeasure ≤[S] 0
hS₃ : 0 ≤[Sᶜ] j₁.toSignedMeasure
hS₄ : j₁.posPart S = 0
hS₅ : j₁.negPart Sᶜ = 0
T : Set α
hT₁ : MeasurableSet T
hT₂ : j₁.toSignedMeasure ≤[T] 0
hT₃ : 0 ≤[Tᶜ] j₁.toSignedMeasure
hT₄ : j₂.posPart T = 0
hT₅ : j₂.negPart Tᶜ = 0
hST₁ : j₁.toSignedMeasure (symmDiff Sᶜ Tᶜ) = 0
i : Set α
hi : MeasurableSet i
⊢ Disjoint (i ∩ S) (i ∩ Sᶜ)

case h
α : Type u_1
inst✝ : MeasurableSpace α
j₁ j₂ : JordanDecomposition α
hj : j₁.toSignedMeasure = j₂.toSignedMeasure
S : Set α
hS₁ : MeasurableSet S
hS₂ : j₁.toSignedMeasure ≤[S] 0
hS₃ : 0 ≤[Sᶜ] j₁.toSignedMeasure
hS₄ : j₁.posPart S = 0
hS₅ : j₁.negPart Sᶜ = 0
T : Set α
hT₁ : MeasurableSet T
hT₂ : j₁.toSignedMeasure ≤[T] 0
hT₃ : 0 ≤[Tᶜ] j₁.toSignedMeasure
hT₄ : j₂.posPart T = 0
hT₅ : j₂.negPart Tᶜ = 0
hST₁ : j₁.toSignedMeasure (symmDiff Sᶜ Tᶜ) = 0
i : Set α
hi : MeasurableSet i
⊢ MeasurableSet (i ∩ Sᶜ)