Theorem: ProbabilityTheory.Kernel.ae_kernel_lt_top
File: Mathlib/Probability/Kernel/Composition.lean

Proof steps:
state_before: α : Type u_1
β : Type u_2
ι : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
γ : Type u_4
mγ : MeasurableSpace γ
s : Set (β × γ)
κ : Kernel α β
inst✝¹ : IsSFiniteKernel κ
η : Kernel (α × β) γ
inst✝ : IsSFiniteKernel η
a✝ a : α
h2s : ((κ ⊗ₖ η) a) s ≠ ⊤
⊢ ∀ᵐ (b : β) ∂κ a, (η (a, b)) (Prod.mk b ⁻¹' s) < ⊤
state_after: α : Type u_1
β : Type u_2
ι : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
γ : Type u_4
mγ : MeasurableSpace γ
s : Set (β × γ)
κ : Kernel α β
inst✝¹ : IsSFiniteKernel κ
η : Kernel (α × β) γ
inst✝ : IsSFiniteKernel η
a✝ a : α
h2s : ((κ ⊗ₖ η) a) s ≠ ⊤
t : Set (β × γ) := toMeasurable ((κ ⊗ₖ η) a) s
⊢ ∀ᵐ (b : β) ∂κ a, (η (a, b)) (Prod.mk b ⁻¹' s) < ⊤
tactic: let t := toMeasurable ((κ ⊗ₖ η) a) s
state_before: α : Type u_1
β : Type u_2
ι : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
γ : Type u_4
mγ : MeasurableSpace γ
s : Set (β × γ)
κ : Kernel α β
inst✝¹ : IsSFiniteKernel κ
η : Kernel (α × β) γ
inst✝ : IsSFiniteKernel η
a✝ a : α
h2s : ((κ ⊗ₖ η) a) s ≠ ⊤
t : Set (β × γ) := toMeasurable ((κ ⊗ₖ η) a) s
⊢ ∀ᵐ (b : β) ∂κ a, (η (a, b)) (Prod.mk b ⁻¹' s) < ⊤
state_after: α : Type u_1
β : Type u_2
ι : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
γ : Type u_4
mγ : MeasurableSpace γ
s : Set (β × γ)
κ : Kernel α β
inst✝¹ : IsSFiniteKernel κ
η : Kernel (α × β) γ
inst✝ : IsSFiniteKernel η
a✝ a : α
h2s : ((κ ⊗ₖ η) a) s ≠ ⊤
t : Set (β × γ) := toMeasurable ((κ ⊗ₖ η) a) s
this : ∀ (b : β), (η (a, b)) (Prod.mk b ⁻¹' s) ≤ (η (a, b)) (Prod.mk b ⁻¹' t)
⊢ ∀ᵐ (b : β) ∂κ a, (η (a, b)) (Prod.mk b ⁻¹' s) < ⊤
tactic: have : ∀ b : β, η (a, b) (Prod.mk b ⁻¹' s) ≤ η (a, b) (Prod.mk b ⁻¹' t) := fun b =>
    measure_mono (Set.preimage_mono (subset_toMeasurable _ _))
state_before: α : Type u_1
β : Type u_2
ι : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
γ : Type u_4
mγ : MeasurableSpace γ
s : Set (β × γ)
κ : Kernel α β
inst✝¹ : IsSFiniteKernel κ
η : Kernel (α × β) γ
inst✝ : IsSFiniteKernel η
a✝ a : α
h2s : ((κ ⊗ₖ η) a) s ≠ ⊤
t : Set (β × γ) := toMeasurable ((κ ⊗ₖ η) a) s
this : ∀ (b : β), (η (a, b)) (Prod.mk b ⁻¹' s) ≤ (η (a, b)) (Prod.mk b ⁻¹' t)
⊢ ∀ᵐ (b : β) ∂κ a, (η (a, b)) (Prod.mk b ⁻¹' s) < ⊤
state_after: α : Type u_1
β : Type u_2
ι : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
γ : Type u_4
mγ : MeasurableSpace γ
s : Set (β × γ)
κ : Kernel α β
inst✝¹ : IsSFiniteKernel κ
η : Kernel (α × β) γ
inst✝ : IsSFiniteKernel η
a✝ a : α
h2s : ((κ ⊗ₖ η) a) s ≠ ⊤
t : Set (β × γ) := toMeasurable ((κ ⊗ₖ η) a) s
this : ∀ (b : β), (η (a, b)) (Prod.mk b ⁻¹' s) ≤ (η (a, b)) (Prod.mk b ⁻¹' t)
ht : MeasurableSet t
⊢ ∀ᵐ (b : β) ∂κ a, (η (a, b)) (Prod.mk b ⁻¹' s) < ⊤
tactic: have ht : MeasurableSet t := measurableSet_toMeasurable _ _
state_before: α : Type u_1
β : Type u_2
ι : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
γ : Type u_4
mγ : MeasurableSpace γ
s : Set (β × γ)
κ : Kernel α β
inst✝¹ : IsSFiniteKernel κ
η : Kernel (α × β) γ
inst✝ : IsSFiniteKernel η
a✝ a : α
h2s : ((κ ⊗ₖ η) a) s ≠ ⊤
t : Set (β × γ) := toMeasurable ((κ ⊗ₖ η) a) s
this : ∀ (b : β), (η (a, b)) (Prod.mk b ⁻¹' s) ≤ (η (a, b)) (Prod.mk b ⁻¹' t)
ht : MeasurableSet t
⊢ ∀ᵐ (b : β) ∂κ a, (η (a, b)) (Prod.mk b ⁻¹' s) < ⊤
state_after: α : Type u_1
β : Type u_2
ι : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
γ : Type u_4
mγ : MeasurableSpace γ
s : Set (β × γ)
κ : Kernel α β
inst✝¹ : IsSFiniteKernel κ
η : Kernel (α × β) γ
inst✝ : IsSFiniteKernel η
a✝ a : α
h2s : ((κ ⊗ₖ η) a) s ≠ ⊤
t : Set (β × γ) := toMeasurable ((κ ⊗ₖ η) a) s
this : ∀ (b : β), (η (a, b)) (Prod.mk b ⁻¹' s) ≤ (η (a, b)) (Prod.mk b ⁻¹' t)
ht : MeasurableSet t
h2t : ((κ ⊗ₖ η) a) t ≠ ⊤
⊢ ∀ᵐ (b : β) ∂κ a, (η (a, b)) (Prod.mk b ⁻¹' s) < ⊤
tactic: have h2t : (κ ⊗ₖ η) a t ≠ ∞ := by rwa [measure_toMeasurable]
state_before: α : Type u_1
β : Type u_2
ι : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
γ : Type u_4
mγ : MeasurableSpace γ
s : Set (β × γ)
κ : Kernel α β
inst✝¹ : IsSFiniteKernel κ
η : Kernel (α × β) γ
inst✝ : IsSFiniteKernel η
a✝ a : α
h2s : ((κ ⊗ₖ η) a) s ≠ ⊤
t : Set (β × γ) := toMeasurable ((κ ⊗ₖ η) a) s
this : ∀ (b : β), (η (a, b)) (Prod.mk b ⁻¹' s) ≤ (η (a, b)) (Prod.mk b ⁻¹' t)
ht : MeasurableSet t
h2t : ((κ ⊗ₖ η) a) t ≠ ⊤
⊢ ∀ᵐ (b : β) ∂κ a, (η (a, b)) (Prod.mk b ⁻¹' s) < ⊤
state_after: α : Type u_1
β : Type u_2
ι : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
γ : Type u_4
mγ : MeasurableSpace γ
s : Set (β × γ)
κ : Kernel α β
inst✝¹ : IsSFiniteKernel κ
η : Kernel (α × β) γ
inst✝ : IsSFiniteKernel η
a✝ a : α
h2s : ((κ ⊗ₖ η) a) s ≠ ⊤
t : Set (β × γ) := toMeasurable ((κ ⊗ₖ η) a) s
this : ∀ (b : β), (η (a, b)) (Prod.mk b ⁻¹' s) ≤ (η (a, b)) (Prod.mk b ⁻¹' t)
ht : MeasurableSet t
h2t : ((κ ⊗ₖ η) a) t ≠ ⊤
ht_lt_top : ∀ᵐ (b : β) ∂κ a, (η (a, b)) (Prod.mk b ⁻¹' t) < ⊤
⊢ ∀ᵐ (b : β) ∂κ a, (η (a, b)) (Prod.mk b ⁻¹' s) < ⊤
tactic: have ht_lt_top : ∀ᵐ b ∂κ a, η (a, b) (Prod.mk b ⁻¹' t) < ∞ := by
    rw [Kernel.compProd_apply _ _ _ ht] at h2t
    exact ae_lt_top (Kernel.measurable_kernel_prod_mk_left' ht a) h2t
state_before: α : Type u_1
β : Type u_2
ι : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
γ : Type u_4
mγ : MeasurableSpace γ
s : Set (β × γ)
κ : Kernel α β
inst✝¹ : IsSFiniteKernel κ
η : Kernel (α × β) γ
inst✝ : IsSFiniteKernel η
a✝ a : α
h2s : ((κ ⊗ₖ η) a) s ≠ ⊤
t : Set (β × γ) := toMeasurable ((κ ⊗ₖ η) a) s
this : ∀ (b : β), (η (a, b)) (Prod.mk b ⁻¹' s) ≤ (η (a, b)) (Prod.mk b ⁻¹' t)
ht : MeasurableSet t
h2t : ((κ ⊗ₖ η) a) t ≠ ⊤
ht_lt_top : ∀ᵐ (b : β) ∂κ a, (η (a, b)) (Prod.mk b ⁻¹' t) < ⊤
⊢ ∀ᵐ (b : β) ∂κ a, (η (a, b)) (Prod.mk b ⁻¹' s) < ⊤
state_after: case h
α : Type u_1
β : Type u_2
ι : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
γ : Type u_4
mγ : MeasurableSpace γ
s : Set (β × γ)
κ : Kernel α β
inst✝¹ : IsSFiniteKernel κ
η : Kernel (α × β) γ
inst✝ : IsSFiniteKernel η
a✝ a : α
h2s : ((κ ⊗ₖ η) a) s ≠ ⊤
t : Set (β × γ) := toMeasurable ((κ ⊗ₖ η) a) s
this : ∀ (b : β), (η (a, b)) (Prod.mk b ⁻¹' s) ≤ (η (a, b)) (Prod.mk b ⁻¹' t)
ht : MeasurableSet t
h2t : ((κ ⊗ₖ η) a) t ≠ ⊤
ht_lt_top : ∀ᵐ (b : β) ∂κ a, (η (a, b)) (Prod.mk b ⁻¹' t) < ⊤
b : β
hb : (η (a, b)) (Prod.mk b ⁻¹' t) < ⊤
⊢ (η (a, b)) (Prod.mk b ⁻¹' s) < ⊤
tactic: filter_upwards [ht_lt_top] with b hb
state_before: case h
α : Type u_1
β : Type u_2
ι : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
γ : Type u_4
mγ : MeasurableSpace γ
s : Set (β × γ)
κ : Kernel α β
inst✝¹ : IsSFiniteKernel κ
η : Kernel (α × β) γ
inst✝ : IsSFiniteKernel η
a✝ a : α
h2s : ((κ ⊗ₖ η) a) s ≠ ⊤
t : Set (β × γ) := toMeasurable ((κ ⊗ₖ η) a) s
this : ∀ (b : β), (η (a, b)) (Prod.mk b ⁻¹' s) ≤ (η (a, b)) (Prod.mk b ⁻¹' t)
ht : MeasurableSet t
h2t : ((κ ⊗ₖ η) a) t ≠ ⊤
ht_lt_top : ∀ᵐ (b : β) ∂κ a, (η (a, b)) (Prod.mk b ⁻¹' t) < ⊤
b : β
hb : (η (a, b)) (Prod.mk b ⁻¹' t) < ⊤
⊢ (η (a, b)) (Prod.mk b ⁻¹' s) < ⊤
state_after: no goals
tactic: exact (this b).trans_lt hb