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

Goal state before:
pp: case inr
α : Type u_2
β : Type u_3
m0 : MeasurableSpace α
inst✝ : MeasurableSpace β
f : α → β
μ : Measure α
h : ∀ᵐ (x : α) (y : α) ∂μ, f x = f y
hμ : μ ≠ 0
this : (ae μ).NeBot
⊢ AEMeasurable f μ

Tactic:
rcases h.exists with ⟨x, hx⟩

Goal state after:
case inr
α : Type u_2
β : Type u_3
m0 : MeasurableSpace α
inst✝ : MeasurableSpace β
f : α → β
μ : Measure α
h : ∀ᵐ (x : α) (y : α) ∂μ, f x = f y
hμ : μ ≠ 0
this : (ae μ).NeBot
x : α
hx : ∀ᵐ (y : α) ∂μ, f x = f y
⊢ AEMeasurable f μ
Module: Mathlib.MeasureTheory.Measure.Restrict

Goal state before:
pp: case e_f
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
iUnion_P : ⋃ C ∈ Cs, P C ⊆ ⋃ i, s i
P_subset_s : ∀ {i : ι} {C : Finset ι}, i ∈ C → P C ⊆ s i
mem_C : ∀ {i : ι}, i ∈ F → ∀ {C : Finset ι} {x : α}, x ∈ P C → x ∈ s i → i ∈ C
C_subset_C : ∀ {C₁ C₂ : Finset ι}, C₁ ∈ Cs → ∀ {x : α}, x ∈ P C₁ ∩ P C₂ → C₁ ⊆ C₂
C : Finset ι
⊢ ∑ i ∈ F, (G i).indicator (fun C ↦ (μ.restrict (P C)) t) C =
    (↑Cs).indicator (fun C ↦ ∑ i ∈ F, (↑C).indicator (fun x ↦ (μ.restrict (P C)) t) i) C

Tactic:
by_cases hC : C ∈ F.powerset <;> by_cases hC' : C = ∅ <;>
        simp [hC, hC', Cs, G, indicator, -Finset.mem_powerset, -coe_powerset]

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

Goal state before:
pp: α : Type u_1
β : Type u_2
γ : Type u_3
γ₂ : Type u_4
δ : Type u_5
ι✝ : Sort y
s t u : Set α
inst✝¹⁶ : TopologicalSpace α
inst✝¹⁵ : MeasurableSpace α
inst✝¹⁴ : OpensMeasurableSpace α
inst✝¹³ : TopologicalSpace β
inst✝¹² : MeasurableSpace β
inst✝¹¹ : OpensMeasurableSpace β
inst✝¹⁰ : TopologicalSpace γ
inst✝⁹ : MeasurableSpace γ
inst✝⁸ : BorelSpace γ
inst✝⁷ : TopologicalSpace γ₂
inst✝⁶ : MeasurableSpace γ₂
inst✝⁵ : BorelSpace γ₂
inst✝⁴ : MeasurableSpace δ
ι : Type u_6
X : ι → Type u_7
inst✝³ : Subsingleton ι
inst✝² : (i : ι) → TopologicalSpace (X i)
inst✝¹ : (i : ι) → MeasurableSpace (X i)
inst✝ : ∀ (i : ι), OpensMeasurableSpace (X i)
⊢ borel ((i : ι) → X i) ≤ MeasurableSpace.pi

Tactic:
by
    obtain h | h := isEmpty_or_nonempty ι
    · exact fun s _ ↦ Subsingleton.set_cases .empty .univ s
    have := Classical.choice (nonempty_unique ι)
    rw [borel, MeasurableSpace.pi, ciSup_unique]
    refine MeasurableSpace.generateFrom_le fun s hs ↦ MeasurableSpace.measurableSet_comap.2 ?_
    simp +instances only [Pi.topologicalSpace, ciInf_unique, isOpen_induced_eq, Set.mem_image,
      Set.mem_ofPred_eq] at hs
    obtain ⟨t, ht, rfl⟩ := hs
    exact ⟨t, ht.measurableSet, rfl⟩

Goal state after:
Module: Mathlib.Topology.MetricSpace.HausdorffDistance

Goal state before:
pp: case refine_2
α : Type u
inst✝ : PseudoEMetricSpace α
s t : Set α
x : α
xs : x ∈ s
y : α
yt : y ∈ t
⊢ ∀ x ∈ t, ∃ y ∈ s, edist x y ≤ ediam (s ∪ t)

Tactic:
intro z hz
    exact ⟨x, xs, Metric.edist_le_ediam_of_mem (subset_union_right hz) (subset_union_left xs)⟩

Goal state after:
Module: Mathlib.Topology.MetricSpace.Thickening

Goal state before:
pp: α : Type u
inst✝ : PseudoEMetricSpace α
s : Set α
δ : ℝ
hδ : 0 < δ
hs : thickening δ s = s
⊢ ⋂ δ, ⋂ (_ : 0 < δ), thickening δ s ⊆ s

Tactic:
exact Set.iInter₂_subset δ hδ |>.trans_eq hs

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

Goal state before:
pp: α : Type u_1
β : Type u_2
inst✝¹ : MeasurableSpace α
inst✝ : Zero β
r : β
s : Set α
f : α →ₛ β
hr : r ∈ (f.restrict s).range
h0 : r ≠ 0
hs : ¬MeasurableSet s
⊢ r ∈ ⇑f '' s

Tactic:
restrict_of_not_measurable hs

Goal state after:
α : Type u_1
β : Type u_2
inst✝¹ : MeasurableSpace α
inst✝ : Zero β
r : β
s : Set α
f : α →ₛ β
hr : r ∈ SimpleFunc.range 0
h0 : r ≠ 0
hs : ¬MeasurableSet s
⊢ r ∈ ⇑f '' s
Module: Mathlib.Topology.MetricSpace.Thickening

Goal state before:
pp: case hnhds
α : Type u
inst✝¹ : PseudoEMetricSpace α
β : Type u_2
inst✝ : PseudoEMetricSpace β
f : α → β
K : Set α
U : Set β
hK : IsCompact K
ho : IsOpen[PseudoEMetricSpace.toUniformSpace.toTopologicalSpace] U
hf : ∀ x ∈ K, ContinuousAt f x
hKU : MapsTo f K U
x : α
hx : x ∈ K
⊢ ∃ t ∈ 𝓝[K] x, ∃ ε > 0, ∃ V ∈ 𝓝ˢ t, thickening ε (f '' V) ⊆ U

Tactic:
have : {f x} ⊆ U := by rw [singleton_subset_iff]; exact hKU hx

Goal state after:
case hnhds
α : Type u
inst✝¹ : PseudoEMetricSpace α
β : Type u_2
inst✝ : PseudoEMetricSpace β
f : α → β
K : Set α
U : Set β
hK : IsCompact K
ho : IsOpen[PseudoEMetricSpace.toUniformSpace.toTopologicalSpace] U
hf : ∀ x ∈ K, ContinuousAt f x
hKU : MapsTo f K U
x : α
hx : x ∈ K
this : {f x} ⊆ U
⊢ ∃ t ∈ 𝓝[K] x, ∃ ε > 0, ∃ V ∈ 𝓝ˢ t, thickening ε (f '' V) ⊆ U
Module: Mathlib.Topology.Instances.Real.Lemmas

Goal state before:
pp: ⊢ ∀ u ∈ ⋃ a, ⋃ b, ⋃ (_ : a < b), {Ioo ↑a ↑b}, IsOpen u

Tactic:
by simp +contextual [isOpen_Ioo]

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

Goal state before:
pp: α : Type u_1
β : Type u_2
x✝ : MeasurableSpace α
f : α → β
inst✝¹ : TopologicalSpace β
inst✝ : Subsingleton β
⊢ StronglyMeasurable f

Tactic:
by
  let f_sf : α →ₛ β := ⟨f, fun x => ?_, Set.Subsingleton.finite Set.subsingleton_of_subsingleton⟩
  · exact ⟨fun _ => f_sf, fun x => tendsto_const_nhds⟩
  · simp [Set.preimage, eq_iff_true_of_subsingleton]

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

Goal state before:
pp: case inl
α : Type u_1
β : Type u_2
inst✝³ : TopologicalSpace β
m₀ : MeasurableSpace α
μ : Measure α
f : α → β
inst✝² : PseudoMetrizableSpace β
inst✝¹ : MeasurableSpace β
inst✝ : BorelSpace β
H : AEMeasurable f μ
t_sep : IsSeparable ∅
ht : μ = 0
⊢ AEStronglyMeasurable f μ

Tactic:
ht

Goal state after:
case inl
α : Type u_1
β : Type u_2
inst✝³ : TopologicalSpace β
m₀ : MeasurableSpace α
μ : Measure α
f : α → β
inst✝² : PseudoMetrizableSpace β
inst✝¹ : MeasurableSpace β
inst✝ : BorelSpace β
H : AEMeasurable f μ
t_sep : IsSeparable ∅
ht : μ = 0
⊢ AEStronglyMeasurable f 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), Measurable (f n)
h_mono : Monotone f
c : ℝ≥0 → ℝ≥0∞ := ofNNReal
F : α → ℝ≥0∞ := fun a ↦ ⨆ n, f n a
s : α →ₛ ℝ≥0
hsf : ∀ (x : α), ↑(s x) ≤ ⨆ n, f n x
r : ℝ≥0
right✝ ha✝ : ↑r < 1
ha : r < 1
rs : α →ₛ ℝ≥0 := SimpleFunc.map (fun a ↦ r * a) s
eq_rs : SimpleFunc.map c rs = const α ↑r * SimpleFunc.map c s
eq : ∀ (p : ℝ≥0∞), ⇑(SimpleFunc.map c rs) ⁻¹' {p} = ⋃ n, ⇑(SimpleFunc.map c rs) ⁻¹' {p} ∩ {a | p ≤ f n a}
mono : ∀ (r : ℝ≥0∞), Monotone fun n ↦ ⇑(SimpleFunc.map c rs) ⁻¹' {r} ∩ {a | r ≤ f n a}
h_meas : ∀ (n : ℕ), MeasurableSet {a | (SimpleFunc.map c rs) a ≤ f n a}
⊢ ↑r * (SimpleFunc.map c s).lintegral μ = ∑ r ∈ (SimpleFunc.map c rs).range, r * μ (⇑(SimpleFunc.map c rs) ⁻¹' {r})

Tactic:
by
      rw [← const_mul_lintegral, eq_rs, SimpleFunc.lintegral]

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

Goal state before:
pp: α : Type u_1
β : Type u_5
f : α → β
inst✝¹ : SeminormedAddCommGroup β
inst✝ : NormedSpace ℝ β
m : MeasurableSpace α
c : ℝ
hf : StronglyMeasurable f
hc : 0 ≤ c
n : ℕ
x : α
h0 : ¬‖(hf.approx n) x‖ = 0
h : ‖(hf.approx n) x‖ ≤ c
⊢ 1 ≤ c / ‖(hf.approx n) x‖

Tactic:
rwa [one_le_div (lt_of_le_of_ne (norm_nonneg _) (Ne.symm h0))]

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

Goal state before:
pp: α : Type u_1
m : MeasurableSpace α
μ : Measure α
s : Set α
f g : α → ℝ≥0∞
hg : AEMeasurable g (μ.restrict s)
hfg : ∀ᵐ (x : α) ∂μ, x ∈ s → f x ≤ g x
f' : α → ℝ≥0∞
hf'm : Measurable f'
hle : f' ≤ f
hf' : ∫⁻ (a : α) in s, f a ∂μ = ∫⁻ (a : α) in s, f' a ∂μ
⊢ ∀ᵐ (x : α) ∂μ, x ∈ s → f' x ≤ g x

pp: α : Type u_1
m : MeasurableSpace α
μ : Measure α
s : Set α
f g : α → ℝ≥0∞
hg : AEMeasurable g (μ.restrict s)
hfg : ∀ᵐ (x : α) ∂μ, x ∈ s → f x ≤ g x
f' : α → ℝ≥0∞
hf'm : Measurable f'
hle : f' ≤ f
hf' : ∫⁻ (a : α) in s, f a ∂μ = ∫⁻ (a : α) in s, f' a ∂μ
⊢ NullMeasurableSet {x | f' x ≤ g x} (μ.restrict s)

Tactic:
· exact hfg.mono fun x hx hxs ↦ (hle x).trans (hx hxs)

Goal state after:
α : Type u_1
m : MeasurableSpace α
μ : Measure α
s : Set α
f g : α → ℝ≥0∞
hg : AEMeasurable g (μ.restrict s)
hfg : ∀ᵐ (x : α) ∂μ, x ∈ s → f x ≤ g x
f' : α → ℝ≥0∞
hf'm : Measurable f'
hle : f' ≤ f
hf' : ∫⁻ (a : α) in s, f a ∂μ = ∫⁻ (a : α) in s, f' a ∂μ
⊢ NullMeasurableSet {x | f' x ≤ g x} (μ.restrict s)
Module: Mathlib.MeasureTheory.Integral.Lebesgue.Basic

Goal state before:
pp: α : Type u_1
m : MeasurableSpace α
μ : Measure α
f g : α → ℝ≥0∞
s : Set α
hs : MeasurableSet s
hfg : ∀ᵐ (x : α) ∂μ, x ∈ s → f x = g x
⊢ f =ᵐ[μ.restrict s] g

Tactic:
EventuallyEq

Goal state after:
α : Type u_1
m : MeasurableSpace α
μ : Measure α
f g : α → ℝ≥0∞
s : Set α
hs : MeasurableSet s
hfg : ∀ᵐ (x : α) ∂μ, x ∈ s → f x = g x
⊢ ∀ᵐ (x : α) ∂μ.restrict s, f x = g x
Module: Mathlib.MeasureTheory.Function.StronglyMeasurable.AEStronglyMeasurable

Goal state before:
pp: α : Type u_1
G : Type u_5
inst✝⁴ : SeminormedAddCommGroup G
inst✝³ : MeasurableSpace G
inst✝² : BorelSpace G
inst✝¹ : SecondCountableTopology G
f : α → G
_m0 : MeasurableSpace α
μ : Measure α
inst✝ : SigmaFinite μ
⊢ AEFinStronglyMeasurable f μ ↔ AEMeasurable f μ

Tactic:
simp_rw [AEFinStronglyMeasurable, AEMeasurable, finStronglyMeasurable_iff_measurable]

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

Goal state before:
pp: α : Type u_1
m : MeasurableSpace α
μ : Measure α
f : α → ℝ≥0∞
s : Set α
g : α →ₛ ℝ≥0∞
hg : ⇑g ≤ fun a ↦ s.indicator f a
this : ⇑g ≤ f
⊢ g.lintegral μ ≤ ⨆ g, ⨆ (_ : ⇑g ≤ fun a ↦ f a), g.lintegral (μ.restrict s)

Tactic:
refine le_iSup_of_le g (le_iSup_of_le this (le_of_eq ?_))

Goal state after:
α : Type u_1
m : MeasurableSpace α
μ : Measure α
f : α → ℝ≥0∞
s : Set α
g : α →ₛ ℝ≥0∞
hg : ⇑g ≤ fun a ↦ s.indicator f a
this : ⇑g ≤ f
⊢ g.lintegral μ = g.lintegral (μ.restrict s)
Module: Mathlib.MeasureTheory.Integral.Lebesgue.Add

Goal state before:
pp: α : Type u_1
m : MeasurableSpace α
μ : Measure α
ι : Type u_3
f : ι → α → ℝ≥0∞
u : Filter ι
inst✝ : u.IsCountablyGenerated
h_meas : ∀ (i : ι), AEMeasurable (f i) μ
⊢ ∫⁻ (a : α), liminf (fun i ↦ f i a) u ∂μ ≤ liminf (fun i ↦ ∫⁻ (a : α), f i a ∂μ) u

Tactic:
by_cases! hu : ¬ u.NeBot

Goal state after:
case pos
α : Type u_1
m : MeasurableSpace α
μ : Measure α
ι : Type u_3
f : ι → α → ℝ≥0∞
u : Filter ι
inst✝ : u.IsCountablyGenerated
h_meas : ∀ (i : ι), AEMeasurable (f i) μ
hu : ¬u.NeBot
⊢ ∫⁻ (a : α), liminf (fun i ↦ f i a) u ∂μ ≤ liminf (fun i ↦ ∫⁻ (a : α), f i a ∂μ) u

case neg
α : Type u_1
m : MeasurableSpace α
μ : Measure α
ι : Type u_3
f : ι → α → ℝ≥0∞
u : Filter ι
inst✝ : u.IsCountablyGenerated
h_meas : ∀ (i : ι), AEMeasurable (f i) μ
hu : u.NeBot
⊢ ∫⁻ (a : α), liminf (fun i ↦ f i a) u ∂μ ≤ liminf (fun i ↦ ∫⁻ (a : α), f i a ∂μ) u
Module: Mathlib.MeasureTheory.Integral.Lebesgue.Basic

Goal state before:
pp: α : Type u_1
m : MeasurableSpace α
μ : Measure α
f : α → ℝ≥0∞
A B : Set α
hB : MeasurableSet B
hAB : Disjoint A B
⊢ ∫⁻ (a : α), f a ∂(μ.restrict A + μ.restrict B) = ∫⁻ (a : α) in A, f a ∂μ + ∫⁻ (a : α) in B, f a ∂μ

Tactic:
lintegral_add_measure

Goal state after:
α : Type u_1
m : MeasurableSpace α
μ : Measure α
f : α → ℝ≥0∞
A B : Set α
hB : MeasurableSet B
hAB : Disjoint A B
⊢ ∫⁻ (a : α) in A, f a ∂μ + ∫⁻ (a : α) in B, f a ∂μ = ∫⁻ (a : α) in A, f a ∂μ + ∫⁻ (a : α) in B, f a ∂μ
Module: Mathlib.MeasureTheory.Integral.Lebesgue.Add

Goal state before:
pp: α : Type u_1
m : MeasurableSpace α
μ : Measure α
f g : α → ℝ≥0∞
hf : Measurable f
hg : Measurable g
⊢ ⨆ n, (eapprox f n).lintegral μ + (eapprox g n).lintegral μ =
    (⨆ n, (eapprox f n).lintegral μ) + ⨆ n, (eapprox g n).lintegral μ

Tactic:
by
      refine (ENNReal.iSup_add_iSup_of_monotone ?_ ?_).symm <;>
        · intro i j h
          exact SimpleFunc.lintegral_mono (monotone_eapprox _ h) le_rfl

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

Goal state before:
pp: α : Type u_1
m : MeasurableSpace α
μ : Measure α
r : ℝ≥0∞
f : α → ℝ≥0∞
hf : Measurable f
⊢ ⨆ n, r * (eapprox f n).lintegral μ = r * ∫⁻ (a : α), f a ∂μ

Tactic:
by rw [← ENNReal.mul_iSup, lintegral_eq_iSup_eapprox_lintegral hf]

Goal state after:
Module: Mathlib.MeasureTheory.Measure.Decomposition.Exhaustion

Goal state before:
pp: α : Type u_1
mα : MeasurableSpace α
μ ν : Measure α
inst✝ : IsFiniteMeasure ν
this : ∀ (n : ℕ), SigmaFinite (μ.restrict (μ.sigmaFiniteSetGE ν n))
f : ℕ × ℕ → Set α :=
  fun p ↦
    (μ.sigmaFiniteSetWRT' ν)ᶜ ∪ spanningSets (μ.restrict (μ.sigmaFiniteSetGE ν p.1)) p.2 ∩ μ.sigmaFiniteSetGE ν p.1
⊢ (μ.restrict (μ.sigmaFiniteSetWRT' ν)).FiniteSpanningSetsIn (Set.range f)

Tactic:
let e : ℕ ≃ ℕ × ℕ := Nat.pairEquiv.symm

Goal state after:
α : Type u_1
mα : MeasurableSpace α
μ ν : Measure α
inst✝ : IsFiniteMeasure ν
this : ∀ (n : ℕ), SigmaFinite (μ.restrict (μ.sigmaFiniteSetGE ν n))
f : ℕ × ℕ → Set α :=
  fun p ↦
    (μ.sigmaFiniteSetWRT' ν)ᶜ ∪ spanningSets (μ.restrict (μ.sigmaFiniteSetGE ν p.1)) p.2 ∩ μ.sigmaFiniteSetGE ν p.1
e : ℕ ≃ ℕ × ℕ := Nat.pairEquiv.symm
⊢ (μ.restrict (μ.sigmaFiniteSetWRT' ν)).FiniteSpanningSetsIn (Set.range f)
Module: Mathlib.MeasureTheory.Integral.Lebesgue.Add

Goal state before:
pp: α : Type u_1
m : MeasurableSpace α
μ : Measure α
r : ℝ≥0∞
f : α → ℝ≥0∞
hr : r ≠ ∞
h : ¬r = 0
rinv : r * r⁻¹ = 1
⊢ r * r⁻¹ = 1

Tactic:
exact rinv

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

Goal state before:
pp: α : Type u_1
m : MeasurableSpace α
μ : Measure α
r : ℝ≥0∞
f : α → ℝ≥0∞
⊢ (∫⁻ (a : α), f a ∂μ) * r ≤ ∫⁻ (a : α), f a * r ∂μ

Tactic:
simp_rw [mul_comm, lintegral_const_mul_le r f]

Goal state after:
Module: Mathlib.MeasureTheory.Measure.Decomposition.Exhaustion

Goal state before:
pp: case a
α : Type u_1
mα : MeasurableSpace α
μ ν : Measure α
inst✝ : IsFiniteMeasure ν
⊢ ⨆ s, ⨆ (_ : MeasurableSet s), ⨆ (_ : SigmaFinite (μ.restrict s)), ν s ≤ ν (μ.sigmaFiniteSetWRT' ν)

Tactic:
· exact le_of_tendsto' (tendsto_measure_sigmaFiniteSetGE μ ν)
      (fun _ ↦ measure_mono (Set.subset_iUnion _ _))

Goal state after:
Module: Mathlib.MeasureTheory.Measure.Decomposition.Exhaustion

Goal state before:
pp: α : Type u_1
mα : MeasurableSpace α
μ ν : Measure α
s : Set α
inst✝ : IsFiniteMeasure ν
hs_subset : s ⊆ (μ.sigmaFiniteSetWRT' ν)ᶜ
hνs : ν s ≠ 0
this : ∀ t ⊆ (μ.sigmaFiniteSetWRT' ν)ᶜ, s ⊆ t → MeasurableSet t → μ t = ∞
t : Set α
hts : s ⊆ t
⊢ MeasurableSet t → μ t = ∞

Tactic:
ht

Goal state after:
α : Type u_1
mα : MeasurableSpace α
μ ν : Measure α
s : Set α
inst✝ : IsFiniteMeasure ν
hs_subset : s ⊆ (μ.sigmaFiniteSetWRT' ν)ᶜ
hνs : ν s ≠ 0
this : ∀ t ⊆ (μ.sigmaFiniteSetWRT' ν)ᶜ, s ⊆ t → MeasurableSet t → μ t = ∞
t : Set α
hts : s ⊆ t
ht : MeasurableSet t
⊢ μ t = ∞
Module: Mathlib.MeasureTheory.Measure.Decomposition.Exhaustion

Goal state before:
pp: α : Type u_1
mα : MeasurableSpace α
μ ν : Measure α
s : Set α
inst✝ : IsFiniteMeasure ν
hs_subset : s ⊆ (μ.sigmaFiniteSetWRT' ν)ᶜ
hνs : ν s ≠ 0
t : Set α
ht_subset : t ⊆ (μ.sigmaFiniteSetWRT' ν)ᶜ
hst : s ⊆ t
⊢ MeasurableSet t → μ t = ∞

Tactic:
ht

Goal state after:
α : Type u_1
mα : MeasurableSpace α
μ ν : Measure α
s : Set α
inst✝ : IsFiniteMeasure ν
hs_subset : s ⊆ (μ.sigmaFiniteSetWRT' ν)ᶜ
hνs : ν s ≠ 0
t : Set α
ht_subset : t ⊆ (μ.sigmaFiniteSetWRT' ν)ᶜ
hst : s ⊆ t
ht : MeasurableSet t
⊢ μ t = ∞
Module: Mathlib.MeasureTheory.Function.StronglyMeasurable.Basic

Goal state before:
pp: α : Type u_5
E : Type u_6
m m₂ : MeasurableSpace α
inst✝¹ : TopologicalSpace E
inst✝ : Zero E
s : Set α
f : α → E
hs_m : MeasurableSet s
hs : ∀ (t : Set α), MeasurableSet (s ∩ t) → MeasurableSet (s ∩ t)
hf : StronglyMeasurable f
hf_zero : ∀ x ∉ s, f x = 0
hs_m₂ : MeasurableSet s
s✝ : Set { x // x ∈ s }
⊢ MeasurableSet s✝ → MeasurableSet s✝

Tactic:
ht

Goal state after:
α : Type u_5
E : Type u_6
m m₂ : MeasurableSpace α
inst✝¹ : TopologicalSpace E
inst✝ : Zero E
s : Set α
f : α → E
hs_m : MeasurableSet s
hs : ∀ (t : Set α), MeasurableSet (s ∩ t) → MeasurableSet (s ∩ t)
hf : StronglyMeasurable f
hf_zero : ∀ x ∉ s, f x = 0
hs_m₂ : MeasurableSet s
s✝ : Set { x // x ∈ s }
ht : MeasurableSet s✝
⊢ MeasurableSet s✝
Module: Mathlib.Analysis.Normed.Group.InfiniteSum

Goal state before:

Tactic:
‖∑ i ∈ t, f i‖ ≤ ∑ i ∈ t, g i := norm_sum_le_of_le _ this
    _ ≤ ‖∑ i ∈ t, g i‖ := le_abs_self _
    _ < ε := hs _ (ht.mono_right le_sup_left)

Goal state after:
Module: Mathlib.Topology.Perfect

Goal state before:
pp: case refine_3
α : Type u_1
inst✝¹ : TopologicalSpace α
C : Set α
inst✝ : SecondCountableTopology α
hclosed : IsClosed[inst✝¹] C
b : Set (Set α)
bct : b.Countable
left✝ : ∅ ∉ b
bbasis : IsTopologicalBasis b
v : Set (Set α) := {U | U ∈ b ∧ (U ∩ C).Countable}
V : Set α := ⋃ U ∈ v, U
D : Set α := C \ V
Vct : (V ∩ C).Countable
⊢ C = C ∩ V ∪ D

Tactic:
inter_union_sdiff

Goal state after:
case refine_3
α : Type u_1
inst✝¹ : TopologicalSpace α
C : Set α
inst✝ : SecondCountableTopology α
hclosed : IsClosed[inst✝¹] C
b : Set (Set α)
bct : b.Countable
left✝ : ∅ ∉ b
bbasis : IsTopologicalBasis b
v : Set (Set α) := {U | U ∈ b ∧ (U ∩ C).Countable}
V : Set α := ⋃ U ∈ v, U
D : Set α := C \ V
Vct : (V ∩ C).Countable
⊢ C = C
Module: Mathlib.Analysis.Normed.Group.InfiniteSum

Goal state before:
pp: ι : Type u_1
E : Type u_3
inst✝ : SeminormedAddCommGroup E
f : ι → E
g : ι → ℝ
hg : Summable g
h : ∀ᶠ (i : ι) in cofinite, ‖f i‖ ≤ g i
ε : ℝ
hε : ε > 0
s : Finset ι
hs : ∀ (t : Finset ι), Disjoint t s → ‖∑ i ∈ t, g i‖ < ε
⊢ ∃ s, ∀ (t : Finset ι), Disjoint t s → ‖∑ i ∈ t, f i‖ < ε

Tactic:
refine ⟨s ∪ h.toFinset, fun t ht => ?_⟩
  have : ∀ i ∈ t, ‖f i‖ ≤ g i := by
    intro i hi
    simp only [disjoint_left, mem_union, not_or, h.mem_toFinset, Set.mem_compl_iff,
      Classical.not_not] at ht
    exact (ht hi).2
  calc
    ‖∑ i ∈ t, f i‖ ≤ ∑ i ∈ t, g i := norm_sum_le_of_le _ this
    _ ≤ ‖∑ i ∈ t, g i‖ := le_abs_self _
    _ < ε := hs _ (ht.mono_right le_sup_left)

Goal state after:
Module: Mathlib.Analysis.Normed.Group.FunctionSeries

Goal state before:
pp: α : Type u_1
β : Type u_2
F : Type u_3
inst✝¹ : NormedAddCommGroup F
inst✝ : CompleteSpace F
u : α → ℝ
f : α → β → F
hu : Summable u
s : Set β
hfu : ∀ (n : α), ∀ x ∈ s, ‖f n x‖ ≤ u n
ε : ℝ
εpos : ε > 0
t : Finset α
⊢ ∑' (a : { x // x ∉ t }), u ↑a < ε → ∀ x ∈ s, dist (∑' (n : α), f n x) (∑ n ∈ t, f n x) < ε

Tactic:
ht

Goal state after:
α : Type u_1
β : Type u_2
F : Type u_3
inst✝¹ : NormedAddCommGroup F
inst✝ : CompleteSpace F
u : α → ℝ
f : α → β → F
hu : Summable u
s : Set β
hfu : ∀ (n : α), ∀ x ∈ s, ‖f n x‖ ≤ u n
ε : ℝ
εpos : ε > 0
t : Finset α
ht : ∑' (a : { x // x ∉ t }), u ↑a < ε
⊢ ∀ x ∈ s, dist (∑' (n : α), f n x) (∑ n ∈ t, f n x) < ε
Module: Mathlib.Analysis.Normed.Group.InfiniteSum

Goal state before:
pp: case pos
ι : Type u_1
E : Type u_3
inst✝ : SeminormedAddCommGroup E
f : ι → E
g : ι → ℝ
a : ℝ
hg : HasSum g a
h : ∀ (i : ι), ‖f i‖ ≤ g i
hf : Summable f
⊢ ‖∑' (i : ι), f i‖ ≤ a

Tactic:
exact hf.hasSum.norm_le_of_bounded hg h

Goal state after:
Module: Mathlib.Topology.MetricSpace.Gluing

Goal state before:
pp: X : Type u
Y : Type v
Z : Type w
inst✝¹ : MetricSpace X
inst✝ : MetricSpace Y
Φ : Z → X
Ψ : Z → Y
ε : ℝ
val✝¹ : X
val✝ : Y
⊢ glueDist Ψ Φ ε (Sum.inl val✝¹).swap (Sum.inr val✝).swap = glueDist Φ Ψ ε (Sum.inl val✝¹) (Sum.inr val✝)

Tactic:
simp only [glueDist, Sum.swap_inl, Sum.swap_inr, add_comm]

Goal state after:
Module: Mathlib.Topology.MetricSpace.Gluing

Goal state before:
pp: X : Type u
Y : Type v
Z : Type w
inst✝¹ : MetricSpace X
inst✝ : MetricSpace Y
Φ : Z → X
Ψ : Z → Y
ε : ℝ
val✝¹ : Y
val✝ : X
⊢ glueDist Ψ Φ ε (Sum.inr val✝¹).swap (Sum.inl val✝).swap = glueDist Φ Ψ ε (Sum.inr val✝¹) (Sum.inl val✝)

Tactic:
simp only [glueDist, Sum.swap_inl, Sum.swap_inr, add_comm]

Goal state after:
Module: Mathlib.Topology.MetricSpace.Polish

Goal state before:
pp: α : Type u_1
ι : Type u_3
inst✝ : Countable ι
t : ι → TopologicalSpace α
ht : ∀ (i : ι), PolishSpace α
i₀ : ι
hi₀ : ∀ (i : ι), t i ≤ t i₀
u : UniformSpace α
hcomp : CompleteSpace α
hcount : (𝓤 α).IsCountablyGenerated
htop : u.toTopologicalSpace = ⨅ i, t i
this : SecondCountableTopology α
⊢ T1Space α

Tactic:
by let := t i₀; have := ht i₀; infer_instance

Goal state after:
Module: Mathlib.Topology.MetricSpace.Polish

Goal state before:
pp: case refine_4
α : Type u_1
β : Type u_2
inst✝ : MetricSpace α
s : Opens α
t : Set s.CompleteCopy
⊢ IsOpen t ↔ ∀ x ∈ t, ∃ ε > 0, ∀ (y : s.CompleteCopy), dist x y < ε → y ∈ t

Tactic:
refine ⟨fun h x hx ↦ ?_, fun h ↦ isOpen_iff_mem_nhds.2 fun x hx ↦ ?_⟩

Goal state after:
case refine_4.refine_1
α : Type u_1
β : Type u_2
inst✝ : MetricSpace α
s : Opens α
t : Set s.CompleteCopy
h : IsOpen t
x : s.CompleteCopy
hx : x ∈ t
⊢ ∃ ε > 0, ∀ (y : s.CompleteCopy), dist x y < ε → y ∈ t

case refine_4.refine_2
α : Type u_1
β : Type u_2
inst✝ : MetricSpace α
s : Opens α
t : Set s.CompleteCopy
h : ∀ x ∈ t, ∃ ε > 0, ∀ (y : s.CompleteCopy), dist x y < ε → y ∈ t
x : s.CompleteCopy
hx : x ∈ t
⊢ t ∈ 𝓝 x
Module: Mathlib.Topology.MetricSpace.PiNat

Goal state before:
pp: E : ℕ → Type u_1
inst✝¹ : (n : ℕ) → TopologicalSpace (E n)
inst✝ : ∀ (n : ℕ), DiscreteTopology (E n)
⊢ IsTopologicalBasis {s | ∃ x n, s = cylinder x n}

Tactic:
apply isTopologicalBasis_of_isOpen_of_nhds
  · rintro u ⟨x, n, rfl⟩
    apply isOpen_cylinder
  · intro x u hx u_open
    obtain ⟨v, ⟨U, F, -, rfl⟩, xU, Uu⟩ :
        ∃ v ∈ { S : Set (∀ i : ℕ, E i) | ∃ (U : ∀ i : ℕ, Set (E i)) (F : Finset ℕ),
          (∀ i : ℕ, i ∈ F → U i ∈ { s : Set (E i) | IsOpen s }) ∧ S = (F : Set ℕ).pi U },
        x ∈ v ∧ v ⊆ u :=
      (isTopologicalBasis_pi fun n : ℕ => isTopologicalBasis_opens).exists_subset_of_mem_open hx
        u_open
    rcases Finset.bddAbove F with ⟨n, hn⟩
    refine ⟨cylinder x (n + 1), ⟨x, n + 1, rfl⟩, self_mem_cylinder _ _, Subset.trans ?_ Uu⟩
    intro y hy
    suffices ∀ i : ℕ, i ∈ F → y i ∈ U i by simpa
    intro i hi
    have : y i = x i := mem_cylinder_iff.1 hy i ((hn hi).trans_lt (lt_add_one n))
    rw [this]
    simp only [Set.mem_pi, Finset.mem_coe] at xU
    exact xU i hi

Goal state after:
Module: Mathlib.Topology.MetricSpace.PiNat

Goal state before:
pp: case mp
E : ℕ → Type u_1
inst✝¹ : (n : ℕ) → TopologicalSpace (E n)
inst✝ : ∀ (n : ℕ), DiscreteTopology (E n)
s : Set ((n : ℕ) → E n)
⊢ IsOpen[Pi.topologicalSpace] s → ∀ x ∈ s, ∃ ε > 0, ∀ (y : (n : ℕ) → E n), dist x y < ε → y ∈ s

Tactic:
intro hs x hx

Goal state after:
case mp
E : ℕ → Type u_1
inst✝¹ : (n : ℕ) → TopologicalSpace (E n)
inst✝ : ∀ (n : ℕ), DiscreteTopology (E n)
s : Set ((n : ℕ) → E n)
hs : IsOpen[Pi.topologicalSpace] s
x : (n : ℕ) → E n
hx : x ∈ s
⊢ ∃ ε > 0, ∀ (y : (n : ℕ) → E n), dist x y < ε → y ∈ s
Module: Mathlib.Topology.MetricSpace.Gluing

Goal state before:
pp: ι : Type u_1
E : ι → Type u_2
inst✝ : (i : ι) → MetricSpace (E i)
⊢ MetricSpace ((i : ι) × E i)

Tactic:
refine MetricSpace.ofDistTopology Sigma.dist ?_ ?_ Sigma.dist_triangle Sigma.isOpen_iff ?_
  · rintro ⟨i, x⟩
    simp [Sigma.dist]
  · rintro ⟨i, x⟩ ⟨j, y⟩
    rcases eq_or_ne i j with (rfl | h)
    · simp [Sigma.dist, dist_comm]
    · simp only [Sigma.dist, dist_comm, h, h.symm, not_false_iff, dif_neg]
      abel
  · rintro ⟨i, x⟩ ⟨j, y⟩
    rcases eq_or_ne i j with (rfl | hij)
    · simp [Sigma.dist]
    · intro h
      apply (lt_irrefl (1 : ℝ) _).elim
      calc
        1 ≤ Sigma.dist (⟨i, x⟩ : Σ k, E k) ⟨j, y⟩ := Sigma.one_le_dist_of_ne hij _ _
        _ < 1 := by rw [h]; exact zero_lt_one

Goal state after:
Module: Mathlib.Topology.MetricSpace.Gluing

Goal state before:
pp: X : ℕ → Type u
inst✝ : (n : ℕ) → MetricSpace (X n)
f : (n : ℕ) → X n → X (n + 1)
I : ∀ (n : ℕ), Isometry (f n)
n : ℕ
x y : X n
⊢ dist (toInductiveLimit I n x) (toInductiveLimit I n y) = dist x y

Tactic:
change inductiveLimitDist f ⟨n, x⟩ ⟨n, y⟩ = dist x y
    rw [inductiveLimitDist_eq_dist I ⟨n, x⟩ ⟨n, y⟩ n (le_refl n) (le_refl n), leRecOn_self,
      leRecOn_self]

Goal state after: