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

Goal state before:
pp: case refine_2.refine_1
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)
hcap : tᶜ ∩ s ⊆ ⋃ n ∈ {k | ν (t' k) < μ (t' k)}, t' n
hle₂ : ν (tᶜ ∩ s) ≤ ∑' (n : ↑{k | ν (t' k) < μ (t' k)}), ν (t' ↑n)
heq : {k | μ (t' k) ≤ ν (t' k)} ∪ {k | ν (t' k) < μ (t' k)} = univ
⊢ ∀ (a : ℕ) (b : a ∈ {k | μ (t' k) ≤ ν (t' k)}), μ (t' ↑⟨a, b⟩) = min (μ (t' ↑⟨a, b⟩)) (ν (t' ↑⟨a, b⟩))

Tactic:
intro n

Goal state after:
case refine_2.refine_1
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)
hcap : tᶜ ∩ s ⊆ ⋃ n ∈ {k | ν (t' k) < μ (t' k)}, t' n
hle₂ : ν (tᶜ ∩ s) ≤ ∑' (n : ↑{k | ν (t' k) < μ (t' k)}), ν (t' ↑n)
heq : {k | μ (t' k) ≤ ν (t' k)} ∪ {k | ν (t' k) < μ (t' k)} = univ
n : ℕ
⊢ ∀ (b : n ∈ {k | μ (t' k) ≤ ν (t' k)}), μ (t' ↑⟨n, b⟩) = min (μ (t' ↑⟨n, b⟩)) (ν (t' ↑⟨n, b⟩))
Module: Mathlib.MeasureTheory.Measure.AEMeasurable

Goal state before:
pp: α : Type u_2
β : Type u_3
m0 : MeasurableSpace α
inst✝ : MeasurableSpace β
f : α → β
μ ν : Measure α
⊢ AEMeasurable f (μ + ν) ↔ AEMeasurable f μ ∧ AEMeasurable f ν

Tactic:
by
  rw [← sum_cond, aemeasurable_sum_measure_iff, Bool.forall_bool, and_comm]
  rfl

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

Goal state before:
pp: case refine_2.refine_2
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)
hcap : tᶜ ∩ s ⊆ ⋃ n ∈ {k | ν (t' k) < μ (t' k)}, t' n
hle₂ : ν (tᶜ ∩ s) ≤ ∑' (n : ↑{k | ν (t' k) < μ (t' k)}), ν (t' ↑n)
heq : {k | μ (t' k) ≤ ν (t' k)} ∪ {k | ν (t' k) < μ (t' k)} = univ
⊢ ∀ (a : ℕ) (b : a ∈ {k | ν (t' k) < μ (t' k)}), ν (t' ↑⟨a, b⟩) = min (μ (t' ↑⟨a, b⟩)) (ν (t' ↑⟨a, b⟩))

Tactic:
intro n

Goal state after:
case refine_2.refine_2
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)
hcap : tᶜ ∩ s ⊆ ⋃ n ∈ {k | ν (t' k) < μ (t' k)}, t' n
hle₂ : ν (tᶜ ∩ s) ≤ ∑' (n : ↑{k | ν (t' k) < μ (t' k)}), ν (t' ↑n)
heq : {k | μ (t' k) ≤ ν (t' k)} ∪ {k | ν (t' k) < μ (t' k)} = univ
n : ℕ
⊢ ∀ (b : n ∈ {k | ν (t' k) < μ (t' k)}), ν (t' ↑⟨n, b⟩) = min (μ (t' ↑⟨n, b⟩)) (ν (t' ↑⟨n, b⟩))
Module: Mathlib.MeasureTheory.Measure.AEMeasurable

Goal state before:
pp: α : Type u_2
m0 : MeasurableSpace α
μ : Measure α
β : Type u_7
mβ : MeasurableSpace β
inst✝¹ : LinearOrder α
inst✝ : atTop.IsCountablyGenerated
x : α
g : α → β
g_meas : ∀ t > x, AEMeasurable g (μ.restrict (Ioc x t))
this : Nonempty α
u : ℕ → α
hu_tendsto : Tendsto u atTop atTop
Ioi_eq_iUnion : Ioi x = ⋃ n, Ioc x (u n)
⊢ ∀ (i : ℕ), AEMeasurable g (μ.restrict (Ioc x (u i)))

Tactic:
intro n

Goal state after:
α : Type u_2
m0 : MeasurableSpace α
μ : Measure α
β : Type u_7
mβ : MeasurableSpace β
inst✝¹ : LinearOrder α
inst✝ : atTop.IsCountablyGenerated
x : α
g : α → β
g_meas : ∀ t > x, AEMeasurable g (μ.restrict (Ioc x t))
this : Nonempty α
u : ℕ → α
hu_tendsto : Tendsto u atTop atTop
Ioi_eq_iUnion : Ioi x = ⋃ n, Ioc x (u n)
n : ℕ
⊢ AEMeasurable g (μ.restrict (Ioc x (u n)))
Module: Mathlib.MeasureTheory.Measure.AEMeasurable

Goal state before:
pp: case mp
α : Type u_2
β : Type u_3
m0 : MeasurableSpace α
inst✝³ : MeasurableSpace β
μ : Measure α
inst✝² : Zero β
s : Set α
inst✝¹ : MeasurableSingletonClass β
b : β
inst✝ : NeZero b
h : AEMeasurable (s.indicator fun x ↦ b) μ
⊢ NullMeasurableSet s μ

pp: case mpr
α : Type u_2
β : Type u_3
m0 : MeasurableSpace α
inst✝³ : MeasurableSpace β
μ : Measure α
inst✝² : Zero β
s : Set α
inst✝¹ : MeasurableSingletonClass β
b : β
inst✝ : NeZero b
h : NullMeasurableSet s μ
⊢ AEMeasurable (s.indicator fun x ↦ b) μ

Tactic:
· convert! h.nullMeasurable (MeasurableSet.singleton (0 : β)).compl
    rw [indicator_const_preimage_eq_union s {0}ᶜ b]
    simp [NeZero.ne b]

Goal state after:
case mpr
α : Type u_2
β : Type u_3
m0 : MeasurableSpace α
inst✝³ : MeasurableSpace β
μ : Measure α
inst✝² : Zero β
s : Set α
inst✝¹ : MeasurableSingletonClass β
b : β
inst✝ : NeZero b
h : NullMeasurableSet s μ
⊢ AEMeasurable (s.indicator fun x ↦ b) μ
Module: Mathlib.MeasureTheory.Measure.MeasureSpace

Goal state before:
pp: α : Type u_1
m0 : MeasurableSpace α
ι : Type u_8
ι' : Type u_9
f : ι → ι'
hf : Injective f
m : ι → Measure α
⊢ sum (Function.extend f m 0) = sum m

Tactic:
ext s hs
  simp [*, Function.apply_extend (fun μ : Measure α ↦ μ s)]

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

Goal state before:
pp: α : Type u_1
m0 : MeasurableSpace α
μ : Measure α
⊢ ∅ ∈ ae μ ↔ μ = 0

Tactic:
mem_ae_iff,

Goal state after:
α : Type u_1
m0 : MeasurableSpace α
μ : Measure α
⊢ μ ∅ᶜ = 0 ↔ μ = 0
Module: Mathlib.MeasureTheory.Group.Arithmetic

Goal state before:
pp: case zero
α : Type u_1
M : Type u_2
inst✝² : Monoid M
inst✝¹ : MeasurableSpace M
inst✝ : MeasurableMul₂ M
⊢ Measurable fun x ↦ (x, 0).1 ^ (x, 0).2

Tactic:
simp only [pow_zero, ← Pi.one_def, measurable_one]

Goal state after:
Module: Mathlib.MeasureTheory.Group.Arithmetic

Goal state before:
pp: case ofNat
α✝ : Type u_1
M✝ : Type u_2
X : Type u_3
α : Type u_4
β : Type u_5
inst✝⁷ : MeasurableSpace X
inst✝⁶ : SMul M✝ X
m : MeasurableSpace α
mβ : MeasurableSpace β
μ : Measure α
f : α → M✝
g : α → X
inst✝⁵ : MeasurableSpace M✝
inst✝⁴ : MeasurableSMul M✝ X
M : Type u_6
inst✝³ : SubNegMonoid M
inst✝² : MeasurableSpace M
inst✝¹ : MeasurableAdd₂ M
inst✝ : MeasurableNeg M
n : ℕ
⊢ Measurable fun x ↦ (x, Int.ofNat n).2 • (x, Int.ofNat n).1

Tactic:
| ofNat n =>

Goal state after:
Module: Mathlib.MeasureTheory.Constructions.BorelSpace.Order

Goal state before:
pp: α : Type u_1
β : Type u_2
γ : Type u_3
δ : Type u_4
ι : Sort y
s t✝ u : Set α
inst✝³ : TopologicalSpace α
mα : MeasurableSpace α
inst✝² : OpensMeasurableSpace α
mδ : MeasurableSpace δ
inst✝¹ : Preorder α
a b x : α
μ : Measure α
inst✝ : R1Space α
s✝ : Set α
hs : s✝ ∈ cocompact α
t : Set α
ht : IsCompact t
hts : tᶜ ⊆ s✝
⊢ ∃ t ∈ cocompact α, MeasurableSet t ∧ t ⊆ s✝

Tactic:
exact ⟨(closure t)ᶜ, ht.closure.compl_mem_cocompact, isClosed_closure.measurableSet.compl,
      (compl_subset_compl.2 subset_closure).trans hts⟩

Goal state after:
Module: Mathlib.MeasureTheory.Constructions.BorelSpace.Order

Goal state before:
pp: α : Type u_5
inst✝³ : TopologicalSpace α
inst✝² : LinearOrder α
inst✝¹ : OrderTopology α
inst✝ : SecondCountableTopology α
s : Set α
hd : Dense s
hbot : ∀ (x : α), IsBot x → x ∈ s
hIoo : ∀ (x y : α), x < y → Ioo x y = ∅ → x ∈ s
S : Set (Set α) := {S | ∃ l ∈ s, ∃ u ∈ s, l ≤ u ∧ Icc l u = S}
this : MeasurableSpace α := MeasurableSpace.generateFrom S
a : α
t : Set α
hts : t ⊆ s
hc : t.Countable
htd : Dense t
htb : ∀ (x : α), IsBot x → x ∈ s → x ∈ t
b : α
ba : b < a
hb : Ioo b a = ∅
hbs : b ∈ s
x : α
⊢ x < a ↔ ∃ i ≤ x, i ≤ b ∧ i ∈ t ∧ x ≤ b

Tactic:
refine ⟨fun h ↦ ?_, fun ⟨y, yx, hy1, hy2, hy⟩ ↦ by order⟩

Goal state after:
α : Type u_5
inst✝³ : TopologicalSpace α
inst✝² : LinearOrder α
inst✝¹ : OrderTopology α
inst✝ : SecondCountableTopology α
s : Set α
hd : Dense s
hbot : ∀ (x : α), IsBot x → x ∈ s
hIoo : ∀ (x y : α), x < y → Ioo x y = ∅ → x ∈ s
S : Set (Set α) := {S | ∃ l ∈ s, ∃ u ∈ s, l ≤ u ∧ Icc l u = S}
this : MeasurableSpace α := MeasurableSpace.generateFrom S
a : α
t : Set α
hts : t ⊆ s
hc : t.Countable
htd : Dense t
htb : ∀ (x : α), IsBot x → x ∈ s → x ∈ t
b : α
ba : b < a
hb : Ioo b a = ∅
hbs : b ∈ s
x : α
h : x < a
⊢ ∃ i ≤ x, i ≤ b ∧ i ∈ t ∧ x ≤ b
Module: Mathlib.Topology.MetricSpace.HausdorffDistance

Goal state before:
pp: α : Type u
inst✝ : PseudoEMetricSpace α
s₁ s₂ t₁ t₂ : Set α
⊢ hausdorffEDist (s₁ ∪ s₂) (t₁ ∪ t₂) ≤ max (hausdorffEDist s₁ t₁) (hausdorffEDist s₂ t₂)

Tactic:
union_eq_iUnion,

Goal state after:
α : Type u
inst✝ : PseudoEMetricSpace α
s₁ s₂ t₁ t₂ : Set α
⊢ hausdorffEDist (⋃ b, bif b then s₁ else s₂) (⋃ b, bif b then t₁ else t₂) ≤
    max (hausdorffEDist s₁ t₁) (hausdorffEDist s₂ t₂)
Module: Mathlib.Topology.MetricSpace.Thickening

Goal state before:
pp: case refine_1
α : Type u
inst✝ : PseudoEMetricSpace α
δ : ℝ
δ_nn : 0 ≤ δ
s : Set ℝ
hsδ : s ⊆ Ioi δ
hs : ∀ (ε : ℝ), δ < ε → (s ∩ Ioc δ ε).Nonempty
E : Set α
ε : ℝ
hε : ε ∈ s
ε' : ℝ
hε' : ε' ∈ Ioc δ ε
⊢ cthickening δ E ⊆ thickening ε E

Tactic:
have ss := cthickening_subset_thickening' (lt_of_le_of_lt δ_nn hε'.1) hε'.1 E

Goal state after:
case refine_1
α : Type u
inst✝ : PseudoEMetricSpace α
δ : ℝ
δ_nn : 0 ≤ δ
s : Set ℝ
hsδ : s ⊆ Ioi δ
hs : ∀ (ε : ℝ), δ < ε → (s ∩ Ioc δ ε).Nonempty
E : Set α
ε : ℝ
hε : ε ∈ s
ε' : ℝ
hε' : ε' ∈ Ioc δ ε
ss : cthickening δ E ⊆ thickening ε' E
⊢ cthickening δ E ⊆ thickening ε E
Module: Mathlib.Topology.MetricSpace.Thickening

Goal state before:
pp: α : Type u
inst✝ : PseudoEMetricSpace α
δ : ℝ
s : Set α
x : α
r : ℝ≥0∞
h : infEDist x (cthickening δ s) + ENNReal.ofReal δ < r
⊢ infEDist x s < r

Tactic:
← lt_tsub_iff_right,

Goal state after:
α : Type u
inst✝ : PseudoEMetricSpace α
δ : ℝ
s : Set α
x : α
r : ℝ≥0∞
h : infEDist x (cthickening δ s) < r - ENNReal.ofReal δ
⊢ infEDist x s < r
Module: Mathlib.MeasureTheory.Function.SimpleFunc

Goal state before:
pp: α : Type u_1
β : Type u_2
γ : Type u_3
inst✝ : MeasurableSpace α
f : α →ₛ β
g : β → γ
s : Set γ
⊢ ⇑(map g f) ⁻¹' s = ⇑f ⁻¹' ↑({b ∈ f.range | g b ∈ s})

Tactic:
simp only [coe_range, sep_mem_eq, coe_map, Finset.coe_filter,
    ← mem_preimage, inter_comm, preimage_inter_range, ← Finset.mem_coe]
  exact preimage_comp

Goal state after:
Module: Mathlib.MeasureTheory.Constructions.BorelSpace.Metric

Goal state before:
pp: α : Type u_1
inst✝² : PseudoEMetricSpace α
inst✝¹ : MeasurableSpace α
inst✝ : OpensMeasurableSpace α
μ : Measure α
s : Set α
hs : ∃ R > 0, μ (thickening R s) ≠ ∞
⊢ Tendsto (fun r ↦ μ (thickening r s)) (𝓝[>] 0)
    (𝓝 (μ (closure[PseudoEMetricSpace.toUniformSpace.toTopologicalSpace] s)))

Tactic:
rw [closure_eq_iInter_thickening]

Goal state after:
α : Type u_1
inst✝² : PseudoEMetricSpace α
inst✝¹ : MeasurableSpace α
inst✝ : OpensMeasurableSpace α
μ : Measure α
s : Set α
hs : ∃ R > 0, μ (thickening R s) ≠ ∞
⊢ Tendsto (fun r ↦ μ (thickening r s)) (𝓝[>] 0) (𝓝 (μ (⋂ δ, ⋂ (_ : 0 < δ), thickening δ s)))
Module: Mathlib.MeasureTheory.MeasurableSpace.Prod

Goal state before:
pp: case a.refine_1
α : Type u_3
β : Type u_4
C : Set (Set α)
D : Set (Set β)
hC : IsCountablySpanning C
s : Set α
hs : s ∈ C
t : ℕ → Set β
h1t : ∀ (n : ℕ), t n ∈ D
h2t : ⋃ n, t n = univ
⊢ ∀ (b : ℕ), MeasurableSet (s ×ˢ t b)

Tactic:
intro n

Goal state after:
case a.refine_1
α : Type u_3
β : Type u_4
C : Set (Set α)
D : Set (Set β)
hC : IsCountablySpanning C
s : Set α
hs : s ∈ C
t : ℕ → Set β
h1t : ∀ (n : ℕ), t n ∈ D
h2t : ⋃ n, t n = univ
n : ℕ
⊢ MeasurableSet (s ×ˢ t n)
Module: Mathlib.MeasureTheory.Function.SimpleFunc

Goal state before:
pp: α : Type u_1
β : Type u_2
inst✝² : MeasurableSpace α
inst✝¹ : Zero β
inst✝ : Preorder β
s : Set α
f g : α →ₛ β
H : f ≤ g
hs : ¬MeasurableSet s
⊢ f.restrict s ≤ g.restrict s

Tactic:
simp only [restrict_of_not_measurable hs, le_refl]

Goal state after:
Module: Mathlib.MeasureTheory.Function.SimpleFunc

Goal state before:
pp: q : ℚ
⊢ ennrealRatEmbed (Encodable.encode q) = ↑(↑q).toNNReal

Tactic:
ennrealRatEmbed,

Goal state after:
q : ℚ
⊢ ENNReal.ofReal ↑((Encodable.decode (Encodable.encode q)).getD 0) = ↑(↑q).toNNReal
Module: Mathlib.MeasureTheory.Constructions.BorelSpace.Real

Goal state before:
pp: ⊢ IsPiSystem (⋃ a, {Iio ↑a})

Tactic:
by
  convert! isPiSystem_image_Iio (((↑) : ℚ → ℝ) '' univ)
  ext x
  simp only [iUnion_singleton_eq_range, mem_range, image_univ, mem_image, exists_exists_eq_and]

Goal state after:
Module: Mathlib.MeasureTheory.Constructions.BorelSpace.Order

Goal state before:
pp: case h
α : Type u_5
mα : MeasurableSpace α
μ : Measure α
f : α → ℝ≥0∞
hf : Measurable f
s : Set α
hs : MeasurableSet s
t : ℝ≥0
ht : 1 < t
A : μ s = μ (s ∩ f ⁻¹' {0}) + μ (s ∩ f ⁻¹' Ioi 0)
B : μ (s ∩ f ⁻¹' Ioi 0) = μ (s ∩ f ⁻¹' {∞}) + μ (s ∩ f ⁻¹' Ioo 0 ∞)
⊢ ∀ (i : ℤ), MeasurableSet (s ∩ f ⁻¹' Ico (↑t ^ i) (↑t ^ (i + 1)))

Tactic:
intro n

Goal state after:
case h
α : Type u_5
mα : MeasurableSpace α
μ : Measure α
f : α → ℝ≥0∞
hf : Measurable f
s : Set α
hs : MeasurableSet s
t : ℝ≥0
ht : 1 < t
A : μ s = μ (s ∩ f ⁻¹' {0}) + μ (s ∩ f ⁻¹' Ioi 0)
B : μ (s ∩ f ⁻¹' Ioi 0) = μ (s ∩ f ⁻¹' {∞}) + μ (s ∩ f ⁻¹' Ioo 0 ∞)
n : ℤ
⊢ MeasurableSet (s ∩ f ⁻¹' Ico (↑t ^ n) (↑t ^ (n + 1)))
Module: Mathlib.MeasureTheory.Integral.Lebesgue.Basic

Goal state before:
pp: α : Type u_1
m : MeasurableSpace α
μ : Measure α
f : α → ℝ≥0∞
h₀ : ∫⁻ (a : α), f a ∂μ ≠ 0
L : ℕ → ℝ≥0∞
left✝ : StrictMono L
hLf : ∀ (n : ℕ), L n ∈ Ioo ⊥ (∫⁻ (a : α), f a ∂μ)
hL_tendsto : Tendsto L atTop (𝓝 (∫⁻ (a : α), f a ∂μ))
⊢ ∀ (n : ℕ), ∃ g, Measurable g ∧ g ≤ f ∧ L n < ∫⁻ (a : α), g a ∂μ

Tactic:
intro n

Goal state after:
α : Type u_1
m : MeasurableSpace α
μ : Measure α
f : α → ℝ≥0∞
h₀ : ∫⁻ (a : α), f a ∂μ ≠ 0
L : ℕ → ℝ≥0∞
left✝ : StrictMono L
hLf : ∀ (n : ℕ), L n ∈ Ioo ⊥ (∫⁻ (a : α), f a ∂μ)
hL_tendsto : Tendsto L atTop (𝓝 (∫⁻ (a : α), f a ∂μ))
n : ℕ
⊢ ∃ g, Measurable g ∧ g ≤ f ∧ L n < ∫⁻ (a : α), g a ∂μ
Module: Mathlib.MeasureTheory.Function.StronglyMeasurable.Basic

Goal state before:
pp: α : Type u_1
β : Type u_2
f : α → β
inst✝¹ : TopologicalSpace β
inst✝ : Zero β
m : MeasurableSpace α
μ : Measure α
hf_meas : StronglyMeasurable f
t : Set α
ht : MeasurableSet t
hft_zero : ∀ x ∈ tᶜ, f x = 0
htμ this : SigmaFinite (μ.restrict t)
S : ℕ → Set α := spanningSets (μ.restrict t)
⊢ FinStronglyMeasurable f μ

Tactic:
have hS_meas : ∀ n, MeasurableSet (S n) := measurableSet_spanningSets (μ.restrict t)

Goal state after:
α : Type u_1
β : Type u_2
f : α → β
inst✝¹ : TopologicalSpace β
inst✝ : Zero β
m : MeasurableSpace α
μ : Measure α
hf_meas : StronglyMeasurable f
t : Set α
ht : MeasurableSet t
hft_zero : ∀ x ∈ tᶜ, f x = 0
htμ this : SigmaFinite (μ.restrict t)
S : ℕ → Set α := spanningSets (μ.restrict t)
hS_meas : ∀ (n : ℕ), MeasurableSet (S n)
⊢ FinStronglyMeasurable f μ
Module: Mathlib.MeasureTheory.Function.StronglyMeasurable.Basic

Goal state before:
pp: α : Type u_1
β : Type u_2
f : α → β
inst✝¹ : TopologicalSpace β
inst✝ : Zero β
m : MeasurableSpace α
μ : Measure α
hf_meas : StronglyMeasurable f
t : Set α
ht : MeasurableSet t
hft_zero : ∀ x ∈ tᶜ, f x = 0
htμ this : SigmaFinite (μ.restrict t)
S : ℕ → Set α := spanningSets (μ.restrict t)
hS_meas : ∀ (n : ℕ), MeasurableSet (S n)
f_approx : ℕ → α →ₛ β := hf_meas.approx
fs : ℕ → α →ₛ β := fun n ↦ (f_approx n).restrict (S n ∩ t)
⊢ ∀ (n : ℕ), ∀ x ∉ t, (fs n) x = 0

Tactic:
intro n

Goal state after:
α : Type u_1
β : Type u_2
f : α → β
inst✝¹ : TopologicalSpace β
inst✝ : Zero β
m : MeasurableSpace α
μ : Measure α
hf_meas : StronglyMeasurable f
t : Set α
ht : MeasurableSet t
hft_zero : ∀ x ∈ tᶜ, f x = 0
htμ this : SigmaFinite (μ.restrict t)
S : ℕ → Set α := spanningSets (μ.restrict t)
hS_meas : ∀ (n : ℕ), MeasurableSet (S n)
f_approx : ℕ → α →ₛ β := hf_meas.approx
fs : ℕ → α →ₛ β := fun n ↦ (f_approx n).restrict (S n ∩ t)
n : ℕ
⊢ ∀ x ∉ t, (fs n) x = 0
Module: Mathlib.MeasureTheory.Integral.Lebesgue.Add

Goal state before:
pp: α : Type u_1
m : MeasurableSpace α
μ : Measure α
f : ℕ → α → ℝ≥0∞
hf : ∀ (n : ℕ), AEMeasurable (f n) μ
h_mono : ∀ᵐ (x : α) ∂μ, Monotone fun n ↦ f n x
p : α → (ℕ → ℝ≥0∞) → Prop := fun x f' ↦ Monotone f'
hp : ∀ᵐ (x : α) ∂μ, p x fun i ↦ f i x
⊢ Monotone (aeSeq hf p)

Tactic:
intro n

Goal state after:
α : Type u_1
m : MeasurableSpace α
μ : Measure α
f : ℕ → α → ℝ≥0∞
hf : ∀ (n : ℕ), AEMeasurable (f n) μ
h_mono : ∀ᵐ (x : α) ∂μ, Monotone fun n ↦ f n x
p : α → (ℕ → ℝ≥0∞) → Prop := fun x f' ↦ Monotone f'
hp : ∀ᵐ (x : α) ∂μ, p x fun i ↦ f i x
n : ℕ
⊢ ∀ ⦃b : ℕ⦄, n ≤ b → aeSeq hf p n ≤ aeSeq hf p b
Module: Mathlib.MeasureTheory.Integral.Lebesgue.Basic

Goal state before:
pp: α : Type u_1
m : MeasurableSpace α
μ : Measure α
f : α → ℝ≥0∞
h : ∫⁻ (x : α), f x ∂μ ≠ ∞
ε : ℝ≥0∞
hε : ε ≠ 0
ε₂ : ℝ≥0∞
hε₂0 : 0 < ε₂
hε₂ε : ε₂ < ε
ε₁ : ℝ≥0∞
hε₁0 : 0 < ε₁
hε₁₂ : ε₁ < ε₂
φ : α →ₛ ℝ≥0
left✝ : ∀ (x : α), ↑(φ x) ≤ f x
hφ : ∀ (ψ : α →ₛ ℝ≥0), (∀ (x : α), ↑(ψ x) ≤ f x) → (SimpleFunc.map ofNNReal (ψ - φ)).lintegral μ < ε₁
C : ℝ≥0
hC : ∀ (x : α), φ x ≤ C
s : Set α
hs : μ s < (ε₂ - ε₁) / ↑C
ψ : α →ₛ ℝ≥0
hψ : ∀ (x : α), ↑(ψ x) ≤ f x
⊢ (const α ↑C).lintegral (μ.restrict s) + ε₁ = ↑C * μ s + ε₁

Tactic:
simp only [← SimpleFunc.lintegral_eq_lintegral, coe_const, lintegral_const,
        Measure.restrict_apply, MeasurableSet.univ, univ_inter, Function.const]

Goal state after:
Module: Mathlib.MeasureTheory.Function.StronglyMeasurable.Basic

Goal state before:
pp: α : Type u_1
β : Type u_2
f : α → β
inst✝¹ : TopologicalSpace β
inst✝ : Zero β
m : MeasurableSpace α
μ : Measure α
hf_meas : StronglyMeasurable f
t : Set α
ht : MeasurableSet t
hft_zero : ∀ x ∈ tᶜ, f x = 0
htμ this : SigmaFinite (μ.restrict t)
S : ℕ → Set α := spanningSets (μ.restrict t)
hS_meas : ∀ (n : ℕ), MeasurableSet (S n)
f_approx : ℕ → α →ₛ β := hf_meas.approx
fs : ℕ → α →ₛ β := fun n ↦ (f_approx n).restrict (S n ∩ t)
h_fs_t_compl : ∀ (n : ℕ), ∀ x ∉ t, (fs n) x = 0
x : α
hxt : x ∈ t
h : Tendsto (fun n ↦ (f_approx n) x) atTop (𝓝 (f x))
n : ℕ
hn : x ∈ S n
⊢ ∃ n, ∀ (m : ℕ), n ≤ m → x ∈ S m

Tactic:
exact ⟨n, fun m hnm => monotone_spanningSets (μ.restrict t) hnm hn⟩

Goal state after:
Module: Mathlib.MeasureTheory.Integral.Lebesgue.Markov

Goal state before:
pp: α : Type u_1
mα : MeasurableSpace α
μ : Measure α
f g : α → ℝ≥0∞
hfg : f ≤ᵐ[μ] g
hf : ∫⁻ (x : α), f x ∂μ ≠ ∞
hg : AEMeasurable g μ
hgf : ∫⁻ (x : α), g x ∂μ ≤ ∫⁻ (x : α), f x ∂μ
⊢ ∀ (n : ℕ), ∀ᵐ (x : α) ∂μ, g x < f x + (↑n)⁻¹

Tactic:
intro n

Goal state after:
α : Type u_1
mα : MeasurableSpace α
μ : Measure α
f g : α → ℝ≥0∞
hfg : f ≤ᵐ[μ] g
hf : ∫⁻ (x : α), f x ∂μ ≠ ∞
hg : AEMeasurable g μ
hgf : ∫⁻ (x : α), g x ∂μ ≤ ∫⁻ (x : α), f x ∂μ
n : ℕ
⊢ ∀ᵐ (x : α) ∂μ, g x < f x + (↑n)⁻¹
Module: Mathlib.MeasureTheory.Integral.Lebesgue.Sub

Goal state before:
pp: α : Type u_1
inst✝ : MeasurableSpace α
μ : Measure α
f : ℕ → α → ℝ≥0∞
h_meas : ∀ (n : ℕ), AEMeasurable (f n) μ
h_anti : ∀ᵐ (a : α) ∂μ, Antitone fun i ↦ f i a
h_fin : ∫⁻ (a : α), f 0 a ∂μ ≠ ∞
p : α → (ℕ → ℝ≥0∞) → Prop := fun x f' ↦ Antitone f'
hp : ∀ᵐ (x : α) ∂μ, p x fun i ↦ f i x
⊢ Antitone (aeSeq h_meas p)

Tactic:
intro n

Goal state after:
α : Type u_1
inst✝ : MeasurableSpace α
μ : Measure α
f : ℕ → α → ℝ≥0∞
h_meas : ∀ (n : ℕ), AEMeasurable (f n) μ
h_anti : ∀ᵐ (a : α) ∂μ, Antitone fun i ↦ f i a
h_fin : ∫⁻ (a : α), f 0 a ∂μ ≠ ∞
p : α → (ℕ → ℝ≥0∞) → Prop := fun x f' ↦ Antitone f'
hp : ∀ᵐ (x : α) ∂μ, p x fun i ↦ f i x
n : ℕ
⊢ ∀ ⦃b : ℕ⦄, n ≤ b → aeSeq h_meas p b ≤ aeSeq h_meas p n
Module: Mathlib.MeasureTheory.Integral.Lebesgue.Add

Goal state before:
pp: case hf
α : Type u_1
m : MeasurableSpace α
μ : Measure α
f : α → ℝ≥0∞
hf : Measurable f
⊢ ∀ (n : ℕ), Measurable ⇑(eapprox f n)

pp: case h_mono
α : Type u_1
m : MeasurableSpace α
μ : Measure α
f : α → ℝ≥0∞
hf : Measurable f
⊢ Monotone fun n ↦ ⇑(eapprox f n)

Tactic:
· fun_prop

Goal state after:
case h_mono
α : Type u_1
m : MeasurableSpace α
μ : Measure α
f : α → ℝ≥0∞
hf : Measurable f
⊢ Monotone fun n ↦ ⇑(eapprox f n)
Module: Mathlib.MeasureTheory.Integral.Lebesgue.Add

Goal state before:
pp: case hf
α : Type u_1
m : MeasurableSpace α
μ : Measure α
f g : α → ℝ≥0∞
hf : Measurable f
hg : Measurable g
⊢ ∀ (n : ℕ), Measurable (⇑(eapprox f n) + ⇑(eapprox g n))

pp: case h_mono
α : Type u_1
m : MeasurableSpace α
μ : Measure α
f g : α → ℝ≥0∞
hf : Measurable f
hg : Measurable g
⊢ Monotone fun n ↦ ⇑(eapprox f n) + ⇑(eapprox g n)

Tactic:
· fun_prop

Goal state after:
case h_mono
α : Type u_1
m : MeasurableSpace α
μ : Measure α
f g : α → ℝ≥0∞
hf : Measurable f
hg : Measurable g
⊢ Monotone fun n ↦ ⇑(eapprox f n) + ⇑(eapprox g n)
Module: Mathlib.MeasureTheory.Function.StronglyMeasurable.Basic

Goal state before:
pp: α : Type u_1
β : Type u_2
f : α → β
m : MeasurableSpace α
inst✝³ : TopologicalSpace β
inst✝² : PseudoMetrizableSpace β
inst✝¹ : MeasurableSpace β
inst✝ : BorelSpace β
x✝ : Measurable f ∧ IsSeparable (range f)
Hm : Measurable f
Hsep : IsSeparable (range f)
⊢ StronglyMeasurable f

Tactic:
have := Hsep.secondCountableTopology

Goal state after:
α : Type u_1
β : Type u_2
f : α → β
m : MeasurableSpace α
inst✝³ : TopologicalSpace β
inst✝² : PseudoMetrizableSpace β
inst✝¹ : MeasurableSpace β
inst✝ : BorelSpace β
x✝ : Measurable f ∧ IsSeparable (range f)
Hm : Measurable f
Hsep : IsSeparable (range f)
this : SecondCountableTopology ↑(range f)
⊢ StronglyMeasurable f
Module: Mathlib.MeasureTheory.Function.StronglyMeasurable.Basic

Goal state before:
pp: case inl
α : Type u_1
β : Type u_2
inst✝⁴ : MeasurableSpace α
inst✝³ : TopologicalSpace α
inst✝² : OpensMeasurableSpace α
inst✝¹ : TopologicalSpace β
inst✝ : PseudoMetrizableSpace β
h : SecondCountableTopologyEither α β
f : α → β
hf : Continuous[inst✝³, inst✝¹] f
this✝¹ : MeasurableSpace β := borel β
this✝ : BorelSpace β
h✝ : SecondCountableTopology α
⊢ StronglyMeasurable f

Tactic:
rw [stronglyMeasurable_iff_measurable_separable]
    refine ⟨hf.measurable, ?_⟩
    exact isSeparable_range hf

Goal state after:
Module: Mathlib.MeasureTheory.Integral.Lebesgue.DominatedConvergence

Goal state before:
pp: case refine_1
α : Type u_1
inst✝ : MeasurableSpace α
μ : Measure α
f : ℕ → α → ℝ≥0∞
g : α → ℝ≥0∞
hf_meas : ∀ (n : ℕ), Measurable (f n)
h_bound : ∀ (n : ℕ), f n ≤ᵐ[μ] g
h_fin : ∫⁻ (a : α), g a ∂μ ≠ ∞
⊢ ∀ (n : ℕ), Measurable fun a ↦ ⨆ i, ⨆ (_ : i ≥ n), f i a

Tactic:
intro n

Goal state after:
case refine_1
α : Type u_1
inst✝ : MeasurableSpace α
μ : Measure α
f : ℕ → α → ℝ≥0∞
g : α → ℝ≥0∞
hf_meas : ∀ (n : ℕ), Measurable (f n)
h_bound : ∀ (n : ℕ), f n ≤ᵐ[μ] g
h_fin : ∫⁻ (a : α), g a ∂μ ≠ ∞
n : ℕ
⊢ Measurable fun a ↦ ⨆ i, ⨆ (_ : i ≥ n), f i a
Module: Mathlib.MeasureTheory.Integral.Lebesgue.DominatedConvergence

Goal state before:
pp: case refine_2
α : Type u_1
inst✝ : MeasurableSpace α
μ : Measure α
f : ℕ → α → ℝ≥0∞
g : α → ℝ≥0∞
hf_meas : ∀ (n : ℕ), Measurable (f n)
h_bound : ∀ (n : ℕ), f n ≤ᵐ[μ] g
h_fin : ∫⁻ (a : α), g a ∂μ ≠ ∞
⊢ Antitone fun n a ↦ ⨆ i, ⨆ (_ : i ≥ n), f i a

Tactic:
intro n

Goal state after:
case refine_2
α : Type u_1
inst✝ : MeasurableSpace α
μ : Measure α
f : ℕ → α → ℝ≥0∞
g : α → ℝ≥0∞
hf_meas : ∀ (n : ℕ), Measurable (f n)
h_bound : ∀ (n : ℕ), f n ≤ᵐ[μ] g
h_fin : ∫⁻ (a : α), g a ∂μ ≠ ∞
n : ℕ
⊢ ∀ ⦃b : ℕ⦄, n ≤ b → (fun n a ↦ ⨆ i, ⨆ (_ : i ≥ n), f i a) b ≤ (fun n a ↦ ⨆ i, ⨆ (_ : i ≥ n), f i a) n
Module: Mathlib.MeasureTheory.Integral.Lebesgue.Add

Goal state before:
pp: α : Type u_1
m : MeasurableSpace α
μ : Measure α
f : α → ℝ≥0∞
hf : Measurable f
g φ : α → ℝ≥0∞
hφm : Measurable φ
hφ_le : φ ≤ fun a ↦ f a + g a
hφ_eq : ∫⁻ (a : α), f a + g a ∂μ = ∫⁻ (a : α), φ a ∂μ
⊢ ∫⁻ (a : α), f a ∂μ + ∫⁻ (a : α), φ a - f a ∂μ ≤ ∫⁻ (a : α), f a ∂μ + ∫⁻ (a : α), g a ∂μ

Tactic:
gcongr with a; exact tsub_le_iff_left.2 <| hφ_le _

Goal state after:
Module: Mathlib.MeasureTheory.Integral.Lebesgue.DominatedConvergence

Goal state before:
pp: α : Type u_1
inst✝ : MeasurableSpace α
μ : Measure α
F : ℕ → α → ℝ≥0∞
f bound : α → ℝ≥0∞
hF_meas : ∀ (n : ℕ), AEMeasurable (F n) μ
h_bound : ∀ (n : ℕ), F n ≤ᵐ[μ] bound
h_fin : ∫⁻ (a : α), bound a ∂μ ≠ ∞
h_lim : ∀ᵐ (a : α) ∂μ, Tendsto (fun n ↦ F n a) atTop (𝓝 (f a))
this : ∀ (n : ℕ), ∫⁻ (a : α), F n a ∂μ = ∫⁻ (a : α), AEMeasurable.mk (F n) ⋯ a ∂μ
⊢ ∀ (n : ℕ), AEMeasurable.mk (F n) ⋯ ≤ᵐ[μ] bound

Tactic:
intro n

Goal state after:
α : Type u_1
inst✝ : MeasurableSpace α
μ : Measure α
F : ℕ → α → ℝ≥0∞
f bound : α → ℝ≥0∞
hF_meas : ∀ (n : ℕ), AEMeasurable (F n) μ
h_bound : ∀ (n : ℕ), F n ≤ᵐ[μ] bound
h_fin : ∫⁻ (a : α), bound a ∂μ ≠ ∞
h_lim : ∀ᵐ (a : α) ∂μ, Tendsto (fun n ↦ F n a) atTop (𝓝 (f a))
this : ∀ (n : ℕ), ∫⁻ (a : α), F n a ∂μ = ∫⁻ (a : α), AEMeasurable.mk (F n) ⋯ a ∂μ
n : ℕ
⊢ AEMeasurable.mk (F n) ⋯ ≤ᵐ[μ] bound