Theorem: MeasureTheory.hasFiniteIntegral_prod_iff'
File: Mathlib/MeasureTheory/Constructions/Prod/Integral.lean

Proof steps:
state_before: α : Type u_1
α' : Type u_2
β : Type u_3
β' : Type u_4
γ : Type u_5
E : Type u_6
inst✝⁶ : MeasurableSpace α
inst✝⁵ : MeasurableSpace α'
inst✝⁴ : MeasurableSpace β
inst✝³ : MeasurableSpace β'
inst✝² : MeasurableSpace γ
μ μ' : Measure α
ν ν' : Measure β
τ : Measure γ
inst✝¹ : NormedAddCommGroup E
inst✝ : SFinite ν
f : α × β → E
h1f : AEStronglyMeasurable f (μ.prod ν)
⊢ HasFiniteIntegral f (μ.prod ν) ↔
    (∀ᵐ (x : α) ∂μ, HasFiniteIntegral (fun y => f (x, y)) ν) ∧ HasFiniteIntegral (fun x => ∫ (y : β), ‖f (x, y)‖ ∂ν) μ
state_after: α : Type u_1
α' : Type u_2
β : Type u_3
β' : Type u_4
γ : Type u_5
E : Type u_6
inst✝⁶ : MeasurableSpace α
inst✝⁵ : MeasurableSpace α'
inst✝⁴ : MeasurableSpace β
inst✝³ : MeasurableSpace β'
inst✝² : MeasurableSpace γ
μ μ' : Measure α
ν ν' : Measure β
τ : Measure γ
inst✝¹ : NormedAddCommGroup E
inst✝ : SFinite ν
f : α × β → E
h1f : AEStronglyMeasurable f (μ.prod ν)
⊢ (∀ᵐ (x : α) ∂μ, HasFiniteIntegral (fun y => AEStronglyMeasurable.mk f h1f (x, y)) ν) ∧
      HasFiniteIntegral (fun x => ∫ (y : β), ‖AEStronglyMeasurable.mk f h1f (x, y)‖ ∂ν) μ ↔
    (∀ᵐ (x : α) ∂μ, HasFiniteIntegral (fun y => f (x, y)) ν) ∧ HasFiniteIntegral (fun x => ∫ (y : β), ‖f (x, y)‖ ∂ν) μ
tactic: rw [hasFiniteIntegral_congr h1f.ae_eq_mk,
    hasFiniteIntegral_prod_iff h1f.stronglyMeasurable_mk]
state_before: α : Type u_1
α' : Type u_2
β : Type u_3
β' : Type u_4
γ : Type u_5
E : Type u_6
inst✝⁶ : MeasurableSpace α
inst✝⁵ : MeasurableSpace α'
inst✝⁴ : MeasurableSpace β
inst✝³ : MeasurableSpace β'
inst✝² : MeasurableSpace γ
μ μ' : Measure α
ν ν' : Measure β
τ : Measure γ
inst✝¹ : NormedAddCommGroup E
inst✝ : SFinite ν
f : α × β → E
h1f : AEStronglyMeasurable f (μ.prod ν)
⊢ (∀ᵐ (x : α) ∂μ, HasFiniteIntegral (fun y => AEStronglyMeasurable.mk f h1f (x, y)) ν) ∧
      HasFiniteIntegral (fun x => ∫ (y : β), ‖AEStronglyMeasurable.mk f h1f (x, y)‖ ∂ν) μ ↔
    (∀ᵐ (x : α) ∂μ, HasFiniteIntegral (fun y => f (x, y)) ν) ∧ HasFiniteIntegral (fun x => ∫ (y : β), ‖f (x, y)‖ ∂ν) μ
state_after: case h₁
α : Type u_1
α' : Type u_2
β : Type u_3
β' : Type u_4
γ : Type u_5
E : Type u_6
inst✝⁶ : MeasurableSpace α
inst✝⁵ : MeasurableSpace α'
inst✝⁴ : MeasurableSpace β
inst✝³ : MeasurableSpace β'
inst✝² : MeasurableSpace γ
μ μ' : Measure α
ν ν' : Measure β
τ : Measure γ
inst✝¹ : NormedAddCommGroup E
inst✝ : SFinite ν
f : α × β → E
h1f : AEStronglyMeasurable f (μ.prod ν)
⊢ (∀ᵐ (x : α) ∂μ, HasFiniteIntegral (fun y => AEStronglyMeasurable.mk f h1f (x, y)) ν) ↔
    ∀ᵐ (x : α) ∂μ, HasFiniteIntegral (fun y => f (x, y)) ν

case h₂
α : Type u_1
α' : Type u_2
β : Type u_3
β' : Type u_4
γ : Type u_5
E : Type u_6
inst✝⁶ : MeasurableSpace α
inst✝⁵ : MeasurableSpace α'
inst✝⁴ : MeasurableSpace β
inst✝³ : MeasurableSpace β'
inst✝² : MeasurableSpace γ
μ μ' : Measure α
ν ν' : Measure β
τ : Measure γ
inst✝¹ : NormedAddCommGroup E
inst✝ : SFinite ν
f : α × β → E
h1f : AEStronglyMeasurable f (μ.prod ν)
⊢ HasFiniteIntegral (fun x => ∫ (y : β), ‖AEStronglyMeasurable.mk f h1f (x, y)‖ ∂ν) μ ↔
    HasFiniteIntegral (fun x => ∫ (y : β), ‖f (x, y)‖ ∂ν) μ
tactic: apply and_congr