Theorem: ProbabilityTheory.Kernel.densityProcess_fst_univ_ae
File: Mathlib/Probability/Kernel/Disintegration/Density.lean

Proof steps:
state_before: α : Type u_1
β : Type u_2
γ : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
inst✝¹ : CountablyGenerated γ
κ✝ : Kernel α (γ × β)
ν : Kernel α γ
κ : Kernel α (γ × β)
inst✝ : IsFiniteKernel κ
n : ℕ
a : α
⊢ ∀ᵐ (x : γ) ∂κ.fst a, κ.densityProcess κ.fst n a x univ = 1
state_after: α : Type u_1
β : Type u_2
γ : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
inst✝¹ : CountablyGenerated γ
κ✝ : Kernel α (γ × β)
ν : Kernel α γ
κ : Kernel α (γ × β)
inst✝ : IsFiniteKernel κ
n : ℕ
a : α
⊢ (κ.fst a) {a_1 | ¬κ.densityProcess κ.fst n a a_1 univ = 1} = 0
tactic: rw [ae_iff]
state_before: α : Type u_1
β : Type u_2
γ : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
inst✝¹ : CountablyGenerated γ
κ✝ : Kernel α (γ × β)
ν : Kernel α γ
κ : Kernel α (γ × β)
inst✝ : IsFiniteKernel κ
n : ℕ
a : α
⊢ (κ.fst a) {a_1 | ¬κ.densityProcess κ.fst n a a_1 univ = 1} = 0
state_after: α : Type u_1
β : Type u_2
γ : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
inst✝¹ : CountablyGenerated γ
κ✝ : Kernel α (γ × β)
ν : Kernel α γ
κ : Kernel α (γ × β)
inst✝ : IsFiniteKernel κ
n : ℕ
a : α
this : {x | ¬κ.densityProcess κ.fst n a x univ = 1} ⊆ {x | (κ.fst a) (countablePartitionSet n x) = 0}
⊢ (κ.fst a) {a_1 | ¬κ.densityProcess κ.fst n a a_1 univ = 1} = 0
tactic: have : {x | ¬ densityProcess κ (fst κ) n a x univ = 1}
      ⊆ {x | fst κ a (countablePartitionSet n x) = 0} := by
    intro x hx
    simp only [mem_setOf_eq] at hx ⊢
    rw [densityProcess_fst_univ] at hx
    simpa using hx
state_before: α : Type u_1
β : Type u_2
γ : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
inst✝¹ : CountablyGenerated γ
κ✝ : Kernel α (γ × β)
ν : Kernel α γ
κ : Kernel α (γ × β)
inst✝ : IsFiniteKernel κ
n : ℕ
a : α
this : {x | ¬κ.densityProcess κ.fst n a x univ = 1} ⊆ {x | (κ.fst a) (countablePartitionSet n x) = 0}
⊢ (κ.fst a) {a_1 | ¬κ.densityProcess κ.fst n a a_1 univ = 1} = 0
state_after: α : Type u_1
β : Type u_2
γ : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
inst✝¹ : CountablyGenerated γ
κ✝ : Kernel α (γ × β)
ν : Kernel α γ
κ : Kernel α (γ × β)
inst✝ : IsFiniteKernel κ
n : ℕ
a : α
this : {x | ¬κ.densityProcess κ.fst n a x univ = 1} ⊆ {x | (κ.fst a) (countablePartitionSet n x) = 0}
⊢ (κ.fst a) {x | (κ.fst a) (countablePartitionSet n x) = 0} = 0
tactic: refine measure_mono_null this ?_
state_before: α : Type u_1
β : Type u_2
γ : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
inst✝¹ : CountablyGenerated γ
κ✝ : Kernel α (γ × β)
ν : Kernel α γ
κ : Kernel α (γ × β)
inst✝ : IsFiniteKernel κ
n : ℕ
a : α
this : {x | ¬κ.densityProcess κ.fst n a x univ = 1} ⊆ {x | (κ.fst a) (countablePartitionSet n x) = 0}
⊢ (κ.fst a) {x | (κ.fst a) (countablePartitionSet n x) = 0} = 0
state_after: α : Type u_1
β : Type u_2
γ : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
inst✝¹ : CountablyGenerated γ
κ✝ : Kernel α (γ × β)
ν : Kernel α γ
κ : Kernel α (γ × β)
inst✝ : IsFiniteKernel κ
n : ℕ
a : α
this✝ : {x | ¬κ.densityProcess κ.fst n a x univ = 1} ⊆ {x | (κ.fst a) (countablePartitionSet n x) = 0}
this : {x | (κ.fst a) (countablePartitionSet n x) = 0} ⊆ ⋃ u ∈ countablePartition γ n, ⋃ (_ : (κ.fst a) u = 0), u
⊢ (κ.fst a) {x | (κ.fst a) (countablePartitionSet n x) = 0} = 0
tactic: have : {x | fst κ a (countablePartitionSet n x) = 0}
      ⊆ ⋃ (u) (_ : u ∈ countablePartition γ n) (_ : fst κ a u = 0), u := by
    intro t ht
    simp only [mem_setOf_eq, mem_iUnion, exists_prop] at ht ⊢
    exact ⟨countablePartitionSet n t, countablePartitionSet_mem _ _, ht,
      mem_countablePartitionSet _ _⟩
state_before: α : Type u_1
β : Type u_2
γ : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
inst✝¹ : CountablyGenerated γ
κ✝ : Kernel α (γ × β)
ν : Kernel α γ
κ : Kernel α (γ × β)
inst✝ : IsFiniteKernel κ
n : ℕ
a : α
this✝ : {x | ¬κ.densityProcess κ.fst n a x univ = 1} ⊆ {x | (κ.fst a) (countablePartitionSet n x) = 0}
this : {x | (κ.fst a) (countablePartitionSet n x) = 0} ⊆ ⋃ u ∈ countablePartition γ n, ⋃ (_ : (κ.fst a) u = 0), u
⊢ (κ.fst a) {x | (κ.fst a) (countablePartitionSet n x) = 0} = 0
state_after: α : Type u_1
β : Type u_2
γ : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
inst✝¹ : CountablyGenerated γ
κ✝ : Kernel α (γ × β)
ν : Kernel α γ
κ : Kernel α (γ × β)
inst✝ : IsFiniteKernel κ
n : ℕ
a : α
this✝ : {x | ¬κ.densityProcess κ.fst n a x univ = 1} ⊆ {x | (κ.fst a) (countablePartitionSet n x) = 0}
this : {x | (κ.fst a) (countablePartitionSet n x) = 0} ⊆ ⋃ u ∈ countablePartition γ n, ⋃ (_ : (κ.fst a) u = 0), u
⊢ (κ.fst a) (⋃ u ∈ countablePartition γ n, ⋃ (_ : (κ.fst a) u = 0), u) = 0
tactic: refine measure_mono_null this ?_
state_before: α : Type u_1
β : Type u_2
γ : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
inst✝¹ : CountablyGenerated γ
κ✝ : Kernel α (γ × β)
ν : Kernel α γ
κ : Kernel α (γ × β)
inst✝ : IsFiniteKernel κ
n : ℕ
a : α
this✝ : {x | ¬κ.densityProcess κ.fst n a x univ = 1} ⊆ {x | (κ.fst a) (countablePartitionSet n x) = 0}
this : {x | (κ.fst a) (countablePartitionSet n x) = 0} ⊆ ⋃ u ∈ countablePartition γ n, ⋃ (_ : (κ.fst a) u = 0), u
⊢ (κ.fst a) (⋃ u ∈ countablePartition γ n, ⋃ (_ : (κ.fst a) u = 0), u) = 0
state_after: α : Type u_1
β : Type u_2
γ : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
inst✝¹ : CountablyGenerated γ
κ✝ : Kernel α (γ × β)
ν : Kernel α γ
κ : Kernel α (γ × β)
inst✝ : IsFiniteKernel κ
n : ℕ
a : α
this✝ : {x | ¬κ.densityProcess κ.fst n a x univ = 1} ⊆ {x | (κ.fst a) (countablePartitionSet n x) = 0}
this : {x | (κ.fst a) (countablePartitionSet n x) = 0} ⊆ ⋃ u ∈ countablePartition γ n, ⋃ (_ : (κ.fst a) u = 0), u
⊢ ∑' (p : ↑(countablePartition γ n)), (κ.fst a) (⋃ (_ : (κ.fst a) ↑p = 0), ↑p) = 0

case hs
α : Type u_1
β : Type u_2
γ : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
inst✝¹ : CountablyGenerated γ
κ✝ : Kernel α (γ × β)
ν : Kernel α γ
κ : Kernel α (γ × β)
inst✝ : IsFiniteKernel κ
n : ℕ
a : α
this✝ : {x | ¬κ.densityProcess κ.fst n a x univ = 1} ⊆ {x | (κ.fst a) (countablePartitionSet n x) = 0}
this : {x | (κ.fst a) (countablePartitionSet n x) = 0} ⊆ ⋃ u ∈ countablePartition γ n, ⋃ (_ : (κ.fst a) u = 0), u
⊢ (countablePartition γ n).Countable

case hd
α : Type u_1
β : Type u_2
γ : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
inst✝¹ : CountablyGenerated γ
κ✝ : Kernel α (γ × β)
ν : Kernel α γ
κ : Kernel α (γ × β)
inst✝ : IsFiniteKernel κ
n : ℕ
a : α
this✝ : {x | ¬κ.densityProcess κ.fst n a x univ = 1} ⊆ {x | (κ.fst a) (countablePartitionSet n x) = 0}
this : {x | (κ.fst a) (countablePartitionSet n x) = 0} ⊆ ⋃ u ∈ countablePartition γ n, ⋃ (_ : (κ.fst a) u = 0), u
⊢ (countablePartition γ n).PairwiseDisjoint fun u => ⋃ (_ : (κ.fst a) u = 0), u

case h
α : Type u_1
β : Type u_2
γ : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
inst✝¹ : CountablyGenerated γ
κ✝ : Kernel α (γ × β)
ν : Kernel α γ
κ : Kernel α (γ × β)
inst✝ : IsFiniteKernel κ
n : ℕ
a : α
this✝ : {x | ¬κ.densityProcess κ.fst n a x univ = 1} ⊆ {x | (κ.fst a) (countablePartitionSet n x) = 0}
this : {x | (κ.fst a) (countablePartitionSet n x) = 0} ⊆ ⋃ u ∈ countablePartition γ n, ⋃ (_ : (κ.fst a) u = 0), u
⊢ ∀ b ∈ countablePartition γ n, MeasurableSet (⋃ (_ : (κ.fst a) b = 0), b)
tactic: rw [measure_biUnion]