mathlib-initiative/mathlib-tactics huggingface dataset:
Module: Mathlib.MeasureTheory.Measure.MeasureSpace

Goal state before:
pp: α : Type u_1
m : MeasurableSpace α
μ : Measure α
ι : Sort u_8
inst✝ : Countable ι
s t : ι → Set α
hsub : ∀ (i : ι), s i ⊆ t i
h_le : ∀ (i : ι), μ (t i) ≤ μ (s i)
⊢ μ (⋃ i, t i) ≤ μ (⋃ i, s i)

Tactic:
by_cases! htop : ∃ i, μ (t i) = ∞

Goal state after:
case pos
α : Type u_1
m : MeasurableSpace α
μ : Measure α
ι : Sort u_8
inst✝ : Countable ι
s t : ι → Set α
hsub : ∀ (i : ι), s i ⊆ t i
h_le : ∀ (i : ι), μ (t i) ≤ μ (s i)
htop : ∃ i, μ (t i) = ∞
⊢ μ (⋃ i, t i) ≤ μ (⋃ i, s i)

case neg
α : Type u_1
m : MeasurableSpace α
μ : Measure α
ι : Sort u_8
inst✝ : Countable ι
s t : ι → Set α
hsub : ∀ (i : ι), s i ⊆ t i
h_le : ∀ (i : ι), μ (t i) ≤ μ (s i)
htop : ∀ (i : ι), μ (t i) ≠ ∞
⊢ μ (⋃ i, t i) ≤ μ (⋃ i, s i)
Module: Mathlib.MeasureTheory.Measure.MeasureSpace

Goal state before:
pp: α : Type u_1
ι : Type u_5
m : MeasurableSpace α
μ : Measure α
inst✝ : Countable ι
s : ι → Set α
hd : Directed (fun x1 x2 ↦ x1 ⊆ x2) s
e : ι → ℕ
he : Injective e
⊢ μ (⋃ i, s i) = ⨆ i, μ (s i)

Tactic:
generalize ht : Function.extend e s ⊥ = t

Goal state after:
α : Type u_1
ι : Type u_5
m : MeasurableSpace α
μ : Measure α
inst✝ : Countable ι
s : ι → Set α
hd : Directed (fun x1 x2 ↦ x1 ⊆ x2) s
e : ι → ℕ
he : Injective e
t : ℕ → Set α
ht : Function.extend e s ⊥ = t
⊢ μ (⋃ i, s i) = ⨆ i, μ (s i)
Module: Mathlib.MeasureTheory.Measure.Typeclasses.SFinite

Goal state before:
pp: α : Type u_1
β : Type u_2
ι : Type u_3
m0 : MeasurableSpace α
inst✝² : MeasurableSpace β
μ ν : Measure α
s t : Set α
a : α
inst✝¹ : Countable ι
m : ι → Measure α
inst✝ : ∀ (n : ι), SFinite (m n)
⊢ SFinite (sum fun i ↦ m i)

Tactic:
[

Goal state after:
α : Type u_1
β : Type u_2
ι : Type u_3
m0 : MeasurableSpace α
inst✝² : MeasurableSpace β
μ ν : Measure α
s t : Set α
a : α
inst✝¹ : Countable ι
m : ι → Measure α
inst✝ : ∀ (n : ι), SFinite (m n)
⊢ SFinite (sum fun i ↦ m i)
Module: Mathlib.MeasureTheory.Measure.Restrict

Goal state before:
pp: R : Type u_1
α : Type u_2
β : Type u_3
δ : Type u_4
γ : Type u_5
ι : Type u_6
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
m0 : MeasurableSpace α
s : Set α
μ : Measure α
s' : Set α
hs' : MeasurableSet s'
t : Set α
this : μ (s ∩ t) = μ (s ∩ t ∩ s') + μ ((s ∩ t) \ s')
⊢ ((OuterMeasure.restrict s) μ.toOuterMeasure) t =
    ((OuterMeasure.restrict s) μ.toOuterMeasure) (t ∩ s') + ((OuterMeasure.restrict s) μ.toOuterMeasure) (t \ s')

Tactic:
by
      simpa [← Set.inter_assoc, Set.inter_comm _ s, ← inter_sdiff_assoc]

Goal state after:
Module: Mathlib.MeasureTheory.Measure.Restrict

Goal state before:
pp: α : Type u_2
m0 : MeasurableSpace α
μ : Measure α
s : Set α
h : MeasurableSet s
⊢ (μ.restrict s).toOuterMeasure = (OuterMeasure.restrict s) μ.toOuterMeasure

Tactic:
[

Goal state after:
α : Type u_2
m0 : MeasurableSpace α
μ : Measure α
s : Set α
h : MeasurableSet s
⊢ (μ.restrict s).toOuterMeasure = (OuterMeasure.restrict s) μ.toOuterMeasure
Module: Mathlib.MeasureTheory.Measure.Typeclasses.SFinite

Goal state before:
pp: α : Type u_1
m0 : MeasurableSpace α
μ : Measure α
inst✝ : SigmaFinite μ
⊢ ⋃ i, spanningSets μ i = univ

Tactic:
[

Goal state after:
α : Type u_1
m0 : MeasurableSpace α
μ : Measure α
inst✝ : SigmaFinite μ
⊢ ⋃ i, spanningSets μ i = univ
Module: Mathlib.MeasureTheory.Measure.Typeclasses.SFinite

Goal state before:
pp: α : Type u_1
ι : Type u_4
x✝ : MeasurableSpace α
μ : Measure α
inst✝ : SFinite μ
As : ι → Set α
As_mble : ∀ (i : ι), NullMeasurableSet (As i) (sum (sfiniteSeq μ))
As_disj : Pairwise (AEDisjoint (sum (sfiniteSeq μ)) on As)
i : ι
hi : 0 < ∑' (i_1 : ℕ), (sfiniteSeq μ i_1) (As i)
con : ∀ (x : ℕ), (sfiniteSeq μ x) (As i) = 0
⊢ False

Tactic:
[

Goal state after:
α : Type u_1
ι : Type u_4
x✝ : MeasurableSpace α
μ : Measure α
inst✝ : SFinite μ
As : ι → Set α
As_mble : ∀ (i : ι), NullMeasurableSet (As i) (sum (sfiniteSeq μ))
As_disj : Pairwise (AEDisjoint (sum (sfiniteSeq μ)) on As)
i : ι
hi : 0 < ∑' (i_1 : ℕ), (sfiniteSeq μ i_1) (As i)
con : ∀ (x : ℕ), (sfiniteSeq μ x) (As i) = 0
⊢ False
Module: Mathlib.MeasureTheory.Measure.Typeclasses.SFinite

Goal state before:
pp: case hs
α : Type u_1
ι : Type u_4
x✝ : MeasurableSpace α
μ : Measure α
inst✝ : SFinite μ
As : ι → Set α
As_mble : ∀ (i : ι), NullMeasurableSet (As i) (sum (sfiniteSeq μ))
As_disj : Pairwise (AEDisjoint (sum (sfiniteSeq μ)) on As)
i : ι
hi : 0 < (sum (sfiniteSeq μ)) (As i)
con : ∀ (x : ℕ), (sfiniteSeq μ x) (As i) = 0
⊢ NullMeasurableSet (As i) (sum (sfiniteSeq μ))

Tactic:
· exact As_mble i

Goal state after:
Module: Mathlib.MeasureTheory.Measure.Restrict

Goal state before:
pp: α : Type u_2
m0 : MeasurableSpace α
μ : Measure α
s : Set α
hs : MeasurableSet s
t : Set α
⊢ μ.restrict (s ∪ t) + μ.restrict (s ∩ t) = μ.restrict s + μ.restrict t

Tactic:
simpa only [union_comm, inter_comm, add_comm] using restrict_union_add_inter t hs

Goal state after:
Module: Mathlib.MeasureTheory.Measure.Restrict

Goal state before:
pp: α : Type u_2
t : Set α
m0 : MeasurableSpace α
m : Set (Measure α)
hm : m.Nonempty
ht : MeasurableSet t
s : Set α
hs : MeasurableSet s
⊢ ((sInf m).restrict t) s = (sInf ((fun μ ↦ μ.restrict t) '' m)) s

Tactic:
[

Goal state after:
α : Type u_2
t : Set α
m0 : MeasurableSpace α
m : Set (Measure α)
hm : m.Nonempty
ht : MeasurableSet t
s : Set α
hs : MeasurableSet s
⊢ ((sInf m).restrict t) s = (sInf ((fun μ ↦ μ.restrict t) '' m)) s
Module: Mathlib.MeasureTheory.Measure.MeasureSpace

Goal state before:
pp: case pos
α : Type u_1
m : MeasurableSpace α
μ : Measure α
ι : Type u_8
inst✝³ : LinearOrder ι
inst✝² : TopologicalSpace ι
inst✝¹ : OrderTopology ι
inst✝ : FirstCountableTopology ι
s : ι → Set α
a : ι
hs : ∀ r > a, NullMeasurableSet (s r) μ
hm : ∀ (i j : ι), a < i → i ≤ j → s i ⊆ s j
hf : ∃ r > a, μ (s r) ≠ ∞
ha : Order.IsPredPrelimit a
⊢ Tendsto (⇑μ ∘ s) (𝓝[>] a) (𝓝 (μ (⋂ r, ⋂ (_ : r > a), s r)))

Tactic:
have : (atBot : Filter (Ioi a)).IsCountablyGenerated := by
      rw [← comap_coe_Ioi_nhdsGT a ha]
      infer_instance

Goal state after:
case pos
α : Type u_1
m : MeasurableSpace α
μ : Measure α
ι : Type u_8
inst✝³ : LinearOrder ι
inst✝² : TopologicalSpace ι
inst✝¹ : OrderTopology ι
inst✝ : FirstCountableTopology ι
s : ι → Set α
a : ι
hs : ∀ r > a, NullMeasurableSet (s r) μ
hm : ∀ (i j : ι), a < i → i ≤ j → s i ⊆ s j
hf : ∃ r > a, μ (s r) ≠ ∞
ha : Order.IsPredPrelimit a
this : atBot.IsCountablyGenerated
⊢ Tendsto (⇑μ ∘ s) (𝓝[>] a) (𝓝 (μ (⋂ r, ⋂ (_ : r > a), s r)))
Module: Mathlib.MeasureTheory.Measure.MeasureSpace

Goal state before:
pp: case pos
α : Type u_1
m : MeasurableSpace α
μ : Measure α
ι : Type u_8
inst✝³ : LinearOrder ι
inst✝² : TopologicalSpace ι
inst✝¹ : OrderTopology ι
inst✝ : FirstCountableTopology ι
s : ι → Set α
a : ι
hs : ∀ r > a, NullMeasurableSet (s r) μ
hm : ∀ (i j : ι), a < i → i ≤ j → s i ⊆ s j
hf : ∃ r > a, μ (s r) ≠ ∞
ha : Order.IsPredPrelimit a
this : atBot.IsCountablyGenerated
⊢ Tendsto (⇑μ ∘ s) (𝓝[>] a) (𝓝 (μ (⋂ r, ⋂ (_ : r > a), s r)))

Tactic:
[

Goal state after:
case pos
α : Type u_1
m : MeasurableSpace α
μ : Measure α
ι : Type u_8
inst✝³ : LinearOrder ι
inst✝² : TopologicalSpace ι
inst✝¹ : OrderTopology ι
inst✝ : FirstCountableTopology ι
s : ι → Set α
a : ι
hs : ∀ r > a, NullMeasurableSet (s r) μ
hm : ∀ (i j : ι), a < i → i ≤ j → s i ⊆ s j
hf : ∃ r > a, μ (s r) ≠ ∞
ha : Order.IsPredPrelimit a
this : atBot.IsCountablyGenerated
⊢ Tendsto (⇑μ ∘ s) (𝓝[>] a) (𝓝 (μ (⋂ r, ⋂ (_ : r > a), s r)))
Module: Mathlib.MeasureTheory.Measure.Typeclasses.SFinite

Goal state before:
pp: α : Type u_1
m0 : MeasurableSpace α
μ : Measure α
s : Set α
hs : MeasurableSet s
t : Set α
v : ℕ → Set α
hv : t ⊆ ⋃ n, v n
h'v : ∀ (n : ℕ), μ (t ∩ v n) ≠ ∞
w : ℕ → Set α := fun n ↦ toMeasurable μ (t ∩ v n)
n : ℕ
⊢ μ (w n) < ∞

Tactic:
[

Goal state after:
α : Type u_1
m0 : MeasurableSpace α
μ : Measure α
s : Set α
hs : MeasurableSet s
t : Set α
v : ℕ → Set α
hv : t ⊆ ⋃ n, v n
h'v : ∀ (n : ℕ), μ (t ∩ v n) ≠ ∞
w : ℕ → Set α := fun n ↦ toMeasurable μ (t ∩ v n)
n : ℕ
⊢ μ (w n) < ∞
Module: Mathlib.MeasureTheory.Measure.Trim

Goal state before:
pp: α : Type u_1
m m0 : MeasurableSpace α
μ : Measure α
s : Set α
hm : m ≤ m0
⊢ μ s ≤ (μ.trim hm) s

Tactic:
[

Goal state after:
α : Type u_1
m m0 : MeasurableSpace α
μ : Measure α
s : Set α
hm : m ≤ m0
⊢ μ s ≤ (μ.trim hm) s
Module: Mathlib.MeasureTheory.Measure.Trim

Goal state before:
pp: α : Type u_1
m m0 : MeasurableSpace α
μ : Measure α
s : Set α
hm : m ≤ m0
hs : (μ.trim hm) s = 0
⊢ (μ.trim hm) (toMeasurable (μ.trim hm) s) = 0

Tactic:
by rwa [@measure_toMeasurable _ m]

Goal state after:
Module: Mathlib.MeasureTheory.Measure.Restrict

Goal state before:
pp: α : Type u_2
ι : Type u_6
m0 : MeasurableSpace α
inst✝ : Countable ι
μ : ι → Measure α
s t : Set α
ht : MeasurableSet t
⊢ ((sum μ).restrict s) t = (sum fun i ↦ (μ i).restrict s) t

Tactic:
[

Goal state after:
α : Type u_2
ι : Type u_6
m0 : MeasurableSpace α
inst✝ : Countable ι
μ : ι → Measure α
s t : Set α
ht : MeasurableSet t
⊢ ((sum μ).restrict s) t = (sum fun i ↦ (μ i).restrict s) t
Module: Mathlib.MeasureTheory.Measure.Restrict

Goal state before:
pp: α : Type u_2
ι : Type u_6
m0 : MeasurableSpace α
μ : Measure α
s : ι → Set α
T : Set ι
hT : Countable ↑T
t : Set α
ht : MeasurableSet t
⊢ (μ.restrict (⋃ i ∈ T, s i)) t ≤ (sum fun i ↦ μ.restrict (s ↑i)) t

Tactic:
by simpa [ht, inter_iUnion] using measure_biUnion_le μ hT (t ∩ s ·)

Goal state after:
Module: Mathlib.Data.Set.MemPartition

Goal state before:
pp: case succ
α : Type u_1
f : ℕ → Set α
n : ℕ
ih : (memPartition f n).Finite
this : Finite ↑(memPartition f n)
⊢ Finite ↑{s | ∃ u ∈ memPartition f n, s = u ∩ f n ∨ s = u \ f n}

Tactic:
[

Goal state after:
case succ
α : Type u_1
f : ℕ → Set α
n : ℕ
ih : (memPartition f n).Finite
this : Finite ↑(memPartition f n)
⊢ Finite ↑{s | ∃ u ∈ memPartition f n, s = u ∩ f n ∨ s = u \ f n}
Module: Mathlib.MeasureTheory.Measure.Restrict

Goal state before:
pp: α : Type u_2
ι : Type u_6
m0 : MeasurableSpace α
μ : Measure α
s : ι → Set α
t : Set ι
ht : t.Countable
p : α → Prop
⊢ (∀ᵐ (x : α) ∂μ.restrict (⋃ i ∈ t, s i), p x) ↔ ∀ i ∈ t, ∀ᵐ (x : α) ∂μ.restrict (s i), p x

Tactic:
[

Goal state after:
α : Type u_2
ι : Type u_6
m0 : MeasurableSpace α
μ : Measure α
s : ι → Set α
t : Set ι
ht : t.Countable
p : α → Prop
⊢ (∀ᵐ (x : α) ∂μ.restrict (⋃ i ∈ t, s i), p x) ↔ ∀ i ∈ t, ∀ᵐ (x : α) ∂μ.restrict (s i), p x
Module: Mathlib.MeasureTheory.Measure.Restrict

Goal state before:
pp: α : Type u_2
ι : Type u_6
m0 : MeasurableSpace α
μ : Measure α
s : ι → Set α
t : Finset ι
p : α → Prop
⊢ (∀ᵐ (x : α) ∂μ.restrict (⋃ i ∈ t, s i), p x) ↔ ∀ i ∈ t, ∀ᵐ (x : α) ∂μ.restrict (s i), p x

Tactic:
[

Goal state after:
α : Type u_2
ι : Type u_6
m0 : MeasurableSpace α
μ : Measure α
s : ι → Set α
t : Finset ι
p : α → Prop
⊢ (∀ᵐ (x : α) ∂μ.restrict (⋃ i ∈ t, s i), p x) ↔ ∀ i ∈ t, ∀ᵐ (x : α) ∂μ.restrict (s i), p x
Module: Mathlib.MeasureTheory.Measure.Restrict

Goal state before:
pp: α : Type u_2
δ : Type u_4
ι : Type u_6
m0 : MeasurableSpace α
μ : Measure α
inst✝ : Countable ι
s : ι → Set α
f g : α → δ
⊢ f =ᵐ[μ.restrict (⋃ i, s i)] g ↔ ∀ (i : ι), f =ᵐ[μ.restrict (s i)] g

Tactic:
[

Goal state after:
α : Type u_2
δ : Type u_4
ι : Type u_6
m0 : MeasurableSpace α
μ : Measure α
inst✝ : Countable ι
s : ι → Set α
f g : α → δ
⊢ f =ᵐ[μ.restrict (⋃ i, s i)] g ↔ ∀ (i : ι), f =ᵐ[μ.restrict (s i)] g
Module: Mathlib.MeasureTheory.Measure.Restrict

Goal state before:
pp: α : Type u_2
δ : Type u_4
ι : Type u_6
m0 : MeasurableSpace α
μ : Measure α
s : ι → Set α
t : Set ι
ht : t.Countable
f g : α → δ
⊢ f =ᵐ[μ.restrict (⋃ i ∈ t, s i)] g ↔ ∀ i ∈ t, f =ᵐ[μ.restrict (s i)] g

Tactic:
[

Goal state after:
α : Type u_2
δ : Type u_4
ι : Type u_6
m0 : MeasurableSpace α
μ : Measure α
s : ι → Set α
t : Set ι
ht : t.Countable
f g : α → δ
⊢ f =ᵐ[μ.restrict (⋃ i ∈ t, s i)] g ↔ ∀ i ∈ t, f =ᵐ[μ.restrict (s i)] g
Module: Mathlib.Data.Set.MemPartition

Goal state before:
pp: α : Type u_1
f : ℕ → Set α
n : ℕ
a : α
s : Set α
hs : s ∈ memPartition f n
⊢ memPartitionSet f n a = s ↔ a ∈ s

Tactic:
by
  refine ⟨fun h ↦ h ▸ mem_memPartitionSet f n a, fun h ↦ ?_⟩
  by_contra h_ne
  have h_disj : Disjoint s (memPartitionSet f n a) :=
    disjoint_memPartition f n hs (memPartitionSet_mem f n a) (Ne.symm h_ne)
  refine absurd h_disj ?_
  rw [not_disjoint_iff_nonempty_inter]
  exact ⟨a, h, mem_memPartitionSet f n a⟩

Goal state after:
Module: Mathlib.MeasureTheory.Measure.Typeclasses.SFinite

Goal state before:
pp: α : Type u_1
m0 : MeasurableSpace α
μ : Measure α
inst✝ : SigmaFinite μ
s : Set α
⊢ ⨆ i, (μ.restrict (spanningSets μ i)) s = ⨆ i, (μ.restrict (spanningSets μ i)) (toMeasurable μ s)

Tactic:
[

Goal state after:
α : Type u_1
m0 : MeasurableSpace α
μ : Measure α
inst✝ : SigmaFinite μ
s : Set α
⊢ ⨆ i, (μ.restrict (spanningSets μ i)) s = ⨆ i, (μ.restrict (spanningSets μ i)) (toMeasurable μ s)
Module: Mathlib.MeasureTheory.MeasurableSpace.CountablyGenerated

Goal state before:
pp: α : Type u_1
β : Type u_2
inst✝¹ : MeasurableSpace α
inst✝ : Countable α
s : Set α
hs : MeasurableSet s
this : s = ⋃ y ∈ s, measurableAtom y
⊢ MeasurableSet s

Tactic:
this

Goal state after:
α : Type u_1
β : Type u_2
inst✝¹ : MeasurableSpace α
inst✝ : Countable α
s : Set α
hs : MeasurableSet s
this : s = ⋃ y ∈ s, measurableAtom y
⊢ MeasurableSet (⋃ y ∈ s, measurableAtom y)
Module: Mathlib.MeasureTheory.Measure.Typeclasses.SFinite

Goal state before:
pp: α : Type u_1
μ : Measure α
h this : SigmaFinite μ
s : ℕ → Set α := spanningSets μ
hs_univ : ⋃ i, s i = univ
hs_meas : ∀ (i : ℕ), MeasurableSet (s i)
⊢ μ univ < ∞

Tactic:
[

Goal state after:
α : Type u_1
μ : Measure α
h this : SigmaFinite μ
s : ℕ → Set α := spanningSets μ
hs_univ : ⋃ i, s i = univ
hs_meas : ∀ (i : ℕ), MeasurableSet (s i)
⊢ μ univ < ∞
Module: Mathlib.MeasureTheory.Measure.Restrict

Goal state before:
pp: α : Type u_2
β : Type u_3
inst✝¹ : MeasurableSpace α
μ : Measure α
s : Set α
f : α → β
inst✝ : Zero β
t : Set β
ht : 0 ∈ t
hs : MeasurableSet s
⊢ t ∈ Filter.map (s.indicator f) (ae μ) ↔ t ∈ Filter.map f (ae (μ.restrict s))

Tactic:
[

Goal state after:
α : Type u_2
β : Type u_3
inst✝¹ : MeasurableSpace α
μ : Measure α
s : Set α
f : α → β
inst✝ : Zero β
t : Set β
ht : 0 ∈ t
hs : MeasurableSet s
⊢ t ∈ Filter.map (s.indicator f) (ae μ) ↔ t ∈ Filter.map f (ae (μ.restrict s))
Module: Mathlib.MeasureTheory.Measure.Restrict

Goal state before:
pp: α : Type u_2
β : Type u_3
inst✝¹ : MeasurableSpace α
μ : Measure α
s : Set α
f : α → β
inst✝ : Zero β
t : Set β
ht : 0 ∈ t
hs : MeasurableSet s
⊢ μ (f ⁻¹' t ∩ s ∪ 0 ⁻¹' t \ s)ᶜ = 0 ↔ μ ((f ⁻¹' t)ᶜ ∩ s) = 0

Tactic:
[

Goal state after:
α : Type u_2
β : Type u_3
inst✝¹ : MeasurableSpace α
μ : Measure α
s : Set α
f : α → β
inst✝ : Zero β
t : Set β
ht : 0 ∈ t
hs : MeasurableSet s
⊢ μ (f ⁻¹' t ∩ s ∪ 0 ⁻¹' t \ s)ᶜ = 0 ↔ μ ((f ⁻¹' t)ᶜ ∩ s) = 0
Module: Mathlib.MeasureTheory.Measure.Restrict

Goal state before:
pp: α : Type u_2
β : Type u_3
inst✝¹ : MeasurableSpace α
μ : Measure α
s : Set α
f : α → β
inst✝ : Zero β
t : Set β
ht : 0 ∈ t
hs : MeasurableSet s
⊢ μ (((f ⁻¹' t)ᶜ ∪ sᶜ) ∩ s) = 0 ↔ μ ((f ⁻¹' t)ᶜ ∩ s) = 0

Tactic:
[

Goal state after:
α : Type u_2
β : Type u_3
inst✝¹ : MeasurableSpace α
μ : Measure α
s : Set α
f : α → β
inst✝ : Zero β
t : Set β
ht : 0 ∈ t
hs : MeasurableSet s
⊢ μ (((f ⁻¹' t)ᶜ ∪ sᶜ) ∩ s) = 0 ↔ μ ((f ⁻¹' t)ᶜ ∩ s) = 0
Module: Mathlib.MeasureTheory.MeasurableSpace.CountablyGenerated

Goal state before:
pp: α : Type u_1
mα : MeasurableSpace α
inst✝ : CountablyGenerated α
x : α
⊢ measurableAtom x = countablyGeneratedAtom α fun x_1 ↦ x ∈ natGeneratingSequence α x_1

Tactic:
let A := natGeneratingSequence α
  have hA : ∀ n, MeasurableSet (A n) := measurableSet_natGeneratingSequence
  have hA_gen : generateFrom (range A) = mα := generateFrom_natGeneratingSequence α
  change measurableAtom x = countablyGeneratedAtom α (x ∈ A ·)
  refine subset_antisymm (measurableAtom_subset ?_ ?_) ?_
  · exact measurableSet_countablyGeneratedAtom _
  · exact mem_countablyGeneratedAtom_natGeneratingSequence x
  classical
  unfold measurableAtom
  simp only [subset_iInter_iff]
  intro s hxs hs
  obtain ⟨q, hq⟩ : ∃ (q : (ℕ → Prop) → Prop), s =
      ⋃ p, if q p then countablyGeneratedAtom α p else ∅ :=
    exists_eq_iUnion_countablyGeneratedAtom hs
  suffices q (x ∈ A ·) by
    rw [hq]
    refine subset_trans (le_of_eq ?_) (subset_iUnion _ (x ∈ A ·))
    simp [this]
  simp only [hq, mem_iUnion, mem_ite_empty_right] at hxs
  obtain ⟨p, hpq, hpx⟩ := hxs
  suffices p = (x ∈ A ·) by rwa [← this]
  by_contra! hp
  have h_disj : Disjoint (countablyGeneratedAtom α p) (countablyGeneratedAtom α (x ∈ A ·)) :=
    disjoint_countablyGeneratedAtom hp
  have hx_mem : x ∈ countablyGeneratedAtom α (x ∈ A ·) :=
    mem_countablyGeneratedAtom_natGeneratingSequence x
  grind

Goal state after:
Module: Mathlib.MeasureTheory.Measure.Typeclasses.SFinite

Goal state before:
pp: case intro.refine_1
α : Type u_1
β : Type u_2
ι✝ : Type u_3
m0 : MeasurableSpace α
inst✝² : MeasurableSpace β
μ✝ ν : Measure α
s t : Set α
a : α
ι : Type u_4
inst✝¹ : Finite ι
μ : ι → Measure α
inst✝ : ∀ (i : ι), SigmaFinite (μ i)
val✝ : Fintype ι
this : ∀ (n : ℕ), MeasurableSet (⋂ i, spanningSets (μ i) n)
n : ℕ
⊢ (sum μ) (⋂ i, spanningSets (μ i) n) < ∞

Tactic:
rw [sum_apply _ (this n), tsum_fintype, ENNReal.sum_lt_top]

Goal state after:
case intro.refine_1
α : Type u_1
β : Type u_2
ι✝ : Type u_3
m0 : MeasurableSpace α
inst✝² : MeasurableSpace β
μ✝ ν : Measure α
s t : Set α
a : α
ι : Type u_4
inst✝¹ : Finite ι
μ : ι → Measure α
inst✝ : ∀ (i : ι), SigmaFinite (μ i)
val✝ : Fintype ι
this : ∀ (n : ℕ), MeasurableSet (⋂ i, spanningSets (μ i) n)
n : ℕ
⊢ ∀ a ∈ Finset.univ, (μ a) (⋂ i, spanningSets (μ i) n) < ∞
Module: Mathlib.MeasureTheory.Measure.Restrict

Goal state before:
pp: case refine_2
α : Type u_2
ι : Type u_6
x✝ : MeasurableSpace α
μ : Measure α
s : ι → Set α
M : ℕ
hs_meas : ∀ (i : ι), MeasurableSet (s i)
hs : ∀ (y : α), {i | y ∈ s i}.encard ≤ ↑M
t : Set α
ht : MeasurableSet t
F : Finset ι
P : Finset ι → Set α := fun C ↦ (⋂ i ∈ C, s i) ∩ ⋂ i ∈ F \ C, (s i)ᶜ
Cs : Finset (Finset ι) := F.powerset \ {∅}
G : ι → Set (Finset ι) := fun i ↦ {C | C ∈ F.powerset ∧ i ∈ C}
P_meas : ∀ (C : Finset ι), MeasurableSet (P C)
i : ι
hi : i ∈ F
x : α
hx : x ∈ s i
⊢ x ∈ P ({x_1 ∈ F | x ∈ s x_1})

Tactic:
[

Goal state after:
case refine_2
α : Type u_2
ι : Type u_6
x✝ : MeasurableSpace α
μ : Measure α
s : ι → Set α
M : ℕ
hs_meas : ∀ (i : ι), MeasurableSet (s i)
hs : ∀ (y : α), {i | y ∈ s i}.encard ≤ ↑M
t : Set α
ht : MeasurableSet t
F : Finset ι
P : Finset ι → Set α := fun C ↦ (⋂ i ∈ C, s i) ∩ ⋂ i ∈ F \ C, (s i)ᶜ
Cs : Finset (Finset ι) := F.powerset \ {∅}
G : ι → Set (Finset ι) := fun i ↦ {C | C ∈ F.powerset ∧ i ∈ C}
P_meas : ∀ (C : Finset ι), MeasurableSet (P C)
i : ι
hi : i ∈ F
x : α
hx : x ∈ s i
⊢ x ∈ P ({x_1 ∈ F | x ∈ s x_1})
Module: Mathlib.MeasureTheory.MeasurableSpace.CountablyGenerated

Goal state before:
pp: α : Type u_1
m m' : MeasurableSpace α
hsep : CountablySeparated α
h : m ≤ m'
⊢ CountablySeparated α

Tactic:
[

Goal state after:
α : Type u_1
m m' : MeasurableSpace α
hsep : CountablySeparated α
h : m ≤ m'
⊢ CountablySeparated α
Module: Mathlib.MeasureTheory.MeasurableSpace.CountablyGenerated

Goal state before:
pp: α : Type u_1
β : Type u_2
inst✝¹ : MeasurableSpace α
inst✝ : MeasurableSingletonClass α
x y : α
h : x ∈ {x} → y ∈ {x}
⊢ x = y

Tactic:
[

Goal state after:
α : Type u_1
β : Type u_2
inst✝¹ : MeasurableSpace α
inst✝ : MeasurableSingletonClass α
x y : α
h : x ∈ {x} → y ∈ {x}
⊢ x = y
Module: Mathlib.MeasureTheory.Measure.Typeclasses.SFinite

Goal state before:
pp: case intro.refine_2
α : Type u_1
β : Type u_2
ι✝ : Type u_3
m0 : MeasurableSpace α
inst✝² : MeasurableSpace β
μ✝ ν : Measure α
s t : Set α
a : α
ι : Type u_4
inst✝¹ : Finite ι
μ : ι → Measure α
inst✝ : ∀ (i : ι), SigmaFinite (μ i)
val✝ : Fintype ι
this : ∀ (n : ℕ), MeasurableSet (⋂ i, spanningSets (μ i) n)
⊢ ⋂ i, ⋃ j, spanningSets (μ i) j = univ

Tactic:
[

Goal state after:
case intro.refine_2
α : Type u_1
β : Type u_2
ι✝ : Type u_3
m0 : MeasurableSpace α
inst✝² : MeasurableSpace β
μ✝ ν : Measure α
s t : Set α
a : α
ι : Type u_4
inst✝¹ : Finite ι
μ : ι → Measure α
inst✝ : ∀ (i : ι), SigmaFinite (μ i)
val✝ : Fintype ι
this : ∀ (n : ℕ), MeasurableSet (⋂ i, spanningSets (μ i) n)
⊢ ⋂ i, ⋃ j, spanningSets (μ i) j = univ
Module: Mathlib.MeasureTheory.MeasurableSpace.CountablyGenerated

Goal state before:
pp: case measurable_invFun
α : Type u_1
inst✝² : MeasurableSpace α
inst✝¹ : CountablyGenerated α
inst✝ : SeparatesPoints α
⊢ autoParam (Measurable ⇑(Equiv.ofInjective (mapNatBool α) ⋯).symm) MeasurableEquiv.measurable_invFun._autoParam

Tactic:
[

Goal state after:
case measurable_invFun
α : Type u_1
inst✝² : MeasurableSpace α
inst✝¹ : CountablyGenerated α
inst✝ : SeparatesPoints α
⊢ autoParam (Measurable ⇑(Equiv.ofInjective (mapNatBool α) ⋯).symm) MeasurableEquiv.measurable_invFun._autoParam
Module: Mathlib.MeasureTheory.Measure.MeasureSpace

Goal state before:
pp: α : Type u_1
m0 : MeasurableSpace α
μ ν : Measure α
s : Set α
hs : MeasurableSet s
t' : ℕ → Set α
ht' : s ⊆ iUnion t'
t : Set α := ⋃ n ∈ {k | μ (t' k) ≤ ν (t' k)}, t' n
ht : t = ⋃ n ∈ {k | μ (t' k) ≤ ν (t' k)}, t' n
hle₁ : μ (t ∩ s) ≤ ∑' (n : ↑{k | μ (t' k) ≤ ν (t' k)}), μ (t' ↑n)
⊢ tᶜ ∩ s ⊆ ⋃ n ∈ {k | ν (t' k) < μ (t' k)}, t' n

Tactic:
[

Goal state after:
α : Type u_1
m0 : MeasurableSpace α
μ ν : Measure α
s : Set α
hs : MeasurableSet s
t' : ℕ → Set α
ht' : s ⊆ iUnion t'
t : Set α := ⋃ n ∈ {k | μ (t' k) ≤ ν (t' k)}, t' n
ht : t = ⋃ n ∈ {k | μ (t' k) ≤ ν (t' k)}, t' n
hle₁ : μ (t ∩ s) ≤ ∑' (n : ↑{k | μ (t' k) ≤ ν (t' k)}), μ (t' ↑n)
⊢ tᶜ ∩ s ⊆ ⋃ n ∈ {k | ν (t' k) < μ (t' k)}, t' n
Module: Mathlib.MeasureTheory.Measure.Restrict

Goal state before:
pp: α : Type u_2
ι : Type u_6
x✝ : MeasurableSpace α
μ : Measure α
s : ι → Set α
M : ℕ
hs_meas : ∀ (i : ι), MeasurableSet (s i)
hs : ∀ (y : α), {i | y ∈ s i}.encard ≤ ↑M
t : Set α
ht : MeasurableSet t
F : Finset ι
P : Finset ι → Set α := fun C ↦ (⋂ i ∈ C, s i) ∩ ⋂ i ∈ F \ C, (s i)ᶜ
Cs : Finset (Finset ι) := F.powerset \ {∅}
G : ι → Set (Finset ι) := fun i ↦ {C | C ∈ F.powerset ∧ i ∈ C}
P_meas : ∀ (C : Finset ι), MeasurableSet (P C)
P_cover : ∀ {i : ι}, i ∈ F → s i ⊆ ⋃ C ∈ G i, P C
x : α
hx : x ∈ ⋃ C ∈ Cs, P C
⊢ x ∈ ⋃ i, s i

Tactic:
[

Goal state after:
α : Type u_2
ι : Type u_6
x✝ : MeasurableSpace α
μ : Measure α
s : ι → Set α
M : ℕ
hs_meas : ∀ (i : ι), MeasurableSet (s i)
hs : ∀ (y : α), {i | y ∈ s i}.encard ≤ ↑M
t : Set α
ht : MeasurableSet t
F : Finset ι
P : Finset ι → Set α := fun C ↦ (⋂ i ∈ C, s i) ∩ ⋂ i ∈ F \ C, (s i)ᶜ
Cs : Finset (Finset ι) := F.powerset \ {∅}
G : ι → Set (Finset ι) := fun i ↦ {C | C ∈ F.powerset ∧ i ∈ C}
P_meas : ∀ (C : Finset ι), MeasurableSet (P C)
P_cover : ∀ {i : ι}, i ∈ F → s i ⊆ ⋃ C ∈ G i, P C
x : α
hx : x ∈ ⋃ C ∈ Cs, P C
⊢ x ∈ ⋃ i, s i
Module: Mathlib.MeasureTheory.MeasurableSpace.CountablyGenerated

Goal state before:
pp: α : Type u_1
t : ℕ → Set α
n : ℕ
⊢ t n = ⋃ u ∈ memPartition t n, u ∩ t n

Tactic:
[

Goal state after:
α : Type u_1
t : ℕ → Set α
n : ℕ
⊢ t n = ⋃ u ∈ memPartition t n, u ∩ t n
Module: Mathlib.MeasureTheory.MeasurableSpace.CountablyGenerated

Goal state before:
pp: α : Type u_1
t : ℕ → Set α
n : ℕ
this : t n = ⋃ u ∈ memPartition t n, u ∩ t n
⊢ MeasurableSet (t n)

Tactic:
this

Goal state after:
α : Type u_1
t : ℕ → Set α
n : ℕ
this : t n = ⋃ u ∈ memPartition t n, u ∩ t n
⊢ MeasurableSet (⋃ u ∈ memPartition t n, u ∩ t n)
Module: Mathlib.MeasureTheory.MeasurableSpace.CountablyGenerated

Goal state before:
pp: case refine_1.succ
α : Type u_1
t : ℕ → Set α
n : ℕ
ih : ∀ u ∈ memPartition t n, MeasurableSet u
u v : Set α
hv : v ∈ memPartition t n
huv : u = v ∩ t n ∨ u = v \ t n
⊢ MeasurableSet u

Tactic:
rcases huv with rfl | rfl

Goal state after:
case refine_1.succ.inl
α : Type u_1
t : ℕ → Set α
n : ℕ
ih : ∀ u ∈ memPartition t n, MeasurableSet u
v : Set α
hv : v ∈ memPartition t n
⊢ MeasurableSet (v ∩ t n)

case refine_1.succ.inr
α : Type u_1
t : ℕ → Set α
n : ℕ
ih : ∀ u ∈ memPartition t n, MeasurableSet u
v : Set α
hv : v ∈ memPartition t n
⊢ MeasurableSet (v \ t n)