mathlib-initiative/mathlib-tactics huggingface dataset:
Module: Mathlib.Topology.IndicatorConstPointwise

Goal state before:
pp: α : Type u_1
A : Set α
β : Type u_2
inst✝¹ : Zero β
inst✝ : TopologicalSpace β
ι : Type u_3
L : Filter ι
As : ι → Set α
b : β
nhds_b : {0}ᶜ ∈ 𝓝 b
nhds_o : {b}ᶜ ∈ 𝓝 0
x : α
⊢ Tendsto (fun i ↦ (As i).indicator (fun x ↦ b) x) L (𝓝 (A.indicator (fun x ↦ b) x)) ↔ ∀ᶠ (i : ι) in L, x ∈ As i ↔ x ∈ A

Tactic:
by
  classical
  have heart := @tendsto_ite ι L β (fun i ↦ x ∈ As i) _ (x ∈ A) _ b 0 (𝓝 b) (𝓝 (0 : β))
                nhds_o nhds_b ?_ ?_
  · convert! heart
    by_cases hxA : x ∈ A <;> simp [hxA]
  · simp only [principal_singleton, le_def, mem_pure]
    exact fun s s_nhds ↦ mem_of_mem_nhds s_nhds
  · simp only [principal_singleton, le_def, mem_pure]
    exact fun s s_nhds ↦ mem_of_mem_nhds s_nhds

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

Goal state before:
pp: ⊢ borel ℝ = generateFrom (⋃ a, {Ici ↑a})

Tactic:
by
  rw [borel_eq_generateFrom_Iio_rat, iUnion_singleton_eq_range, iUnion_singleton_eq_range]
  refine le_antisymm (generateFrom_le ?_) (generateFrom_le ?_) <;>
  rintro _ ⟨q, rfl⟩ <;>
  dsimp only <;>
  [rw [← compl_Ici]; rw [← compl_Iio]] <;>
  exact MeasurableSet.compl (GenerateMeasurable.basic _ (mem_range_self q))

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

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
μ : Measure ℝ
inst✝ : IsLocallyFiniteMeasure μ
n : ℕ
⊢ Ioo (-(↑n + 1)) (↑n + 1) ∈ ⋃ a, ⋃ b, ⋃ (_ : a < b), {Ioo ↑a ↑b}

Tactic:
by
    simp only [mem_iUnion, mem_singleton_iff]
    refine ⟨-(n + 1 : ℕ), n + 1, ?_, by simp⟩
    -- TODO: norm_cast fails here?
    push_cast
    exact neg_lt_self n.cast_add_one_pos

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

Goal state before:
pp: ⊢ Measurable fun p ↦ (↑p).toReal

Tactic:
simpa using! measurable_id

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

Goal state before:
pp: case refine_1
β : Type u_6
mβ : MeasurableSpace β
f : EReal × EReal → β
h_real : Measurable fun p ↦ f (↑p.1, ↑p.2)
h_bot_left : Measurable fun r ↦ f (⊥, ↑r)
h_top_left : Measurable fun r ↦ f (⊤, ↑r)
h_bot_right : Measurable fun r ↦ f (↑r, ⊥)
h_top_right : Measurable fun r ↦ f (↑r, ⊤)
⊢ Measurable fun p ↦ ((fun p ↦ f (↑p.1, p.2)) ∘ Prod.swap) (↑p.1, p.2)

Tactic:
exact h_real.comp measurable_swap

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

Goal state before:
pp: case refine_1
α : Type u_1
β : Type u_2
inst✝³ : TopologicalSpace β
m₀ : MeasurableSpace α
μ : Measure α
ι : Type u_5
inst✝² : PseudoMetrizableSpace β
u : Filter ι
inst✝¹ : u.NeBot
inst✝ : u.IsCountablyGenerated
f : ι → α → β
g : α → β
hf : ∀ (i : ι), AEStronglyMeasurable (f i) μ
lim : ∀ᵐ (x : α) ∂μ, Tendsto (fun n ↦ f n x) u (𝓝 (g x))
this✝¹ : MeasurableSpace β := borel β
this✝ : BorelSpace β
⊢ AEMeasurable g μ

Tactic:
exact aemeasurable_of_tendsto_metrizable_ae _ (fun n => (hf n).aemeasurable) lim

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

Goal state before:
pp: α : Type u_5
β : Type u_6
inst✝² : TopologicalSpace β
inst✝¹ : PseudoMetrizableSpace β
mb : MeasurableSpace β
inst✝ : BorelSpace β
m : MeasurableSpace α
μ : Measure α
f : α → β
hf : AEStronglyMeasurable f μ
s : Set β
hs : MeasurableSet s
h_nonempty : s.Nonempty
h_mem : ∀ᵐ (x : α) ∂μ, f x ∈ s
⊢ ∃ g, StronglyMeasurable g ∧ (∀ (x : α), g x ∈ s) ∧ f =ᵐ[μ] g

Tactic:
by
  obtain ⟨f', hf', hff'⟩ := hf
  classical
  refine ⟨(f' ⁻¹' s).piecewise f' (fun _ ↦ h_nonempty.some), ?meas, ?subset, ?ae_eq⟩
  case meas => exact hf'.piecewise (hf'.measurable hs) stronglyMeasurable_const
  case subset =>
    rw [← Set.range_subset_iff]
    simpa [Set.range_piecewise] using! fun _ _ ↦ h_nonempty.some_mem
  case ae_eq =>
    apply hff'.trans
    filter_upwards [h_mem, hff'] with x hx hx'
    exact Eq.symm <| (f' ⁻¹' s).piecewise_eq_of_mem f' _ (by simpa [hx'] using! hx)

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

Goal state before:
pp: case refine_1
α : Type u_1
β : Type u_2
inst✝¹ : TopologicalSpace β
m₀ : MeasurableSpace α
μ : Measure α
f g : α → β
s : Set α
inst✝ : DecidablePred fun x ↦ x ∈ s
hs : MeasurableSet s
hf : AEStronglyMeasurable f (μ.restrict s)
hg : AEStronglyMeasurable g (μ.restrict sᶜ)
⊢ ∀ᵐ (x : α) ∂μ.restrict s,
    s.piecewise f g x = s.piecewise (AEStronglyMeasurable.mk f hf) (AEStronglyMeasurable.mk g hg) x

Tactic:
have h := hf.ae_eq_mk
    rw [Filter.EventuallyEq, ae_restrict_iff' hs] at h
    rw [ae_restrict_iff' hs]
    filter_upwards [h] with x hx
    intro hx_mem
    simp only [hx_mem, Set.piecewise_eq_of_mem, hx hx_mem]

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 : ∀ (m : ℕ), n ≤ m → x ∈ S m ∩ t
m : ℕ
hnm : n ≤ m
⊢ (fs m) x = (f_approx m) x

Tactic:
simp_rw [fs, SimpleFunc.restrict_apply _ ((hS_meas m).inter ht),
        Set.indicator_of_mem (hn m hnm)]

Goal state after:
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∞
hf : Measurable f
hg : Measurable g
hm : MeasurableSet {x | f x ≤ g x}
⊢ ∫⁻ (x : α) in {x | f x ≤ g x}, max (f x) (g x) ∂μ + ∫⁻ (x : α) in {x | f x ≤ g x}ᶜ, max (f x) (g x) ∂μ =
    ∫⁻ (x : α) in {x | f x ≤ g x}, g x ∂μ + ∫⁻ (x : α) in {x | g x < f x}, f x ∂μ

Tactic:
simp only [← compl_ofPred, ← not_le]

Goal state after:
α : Type u_1
m : MeasurableSpace α
μ : Measure α
f g : α → ℝ≥0∞
hf : Measurable f
hg : Measurable g
hm : MeasurableSet {x | f x ≤ g x}
⊢ ∫⁻ (x : α) in {x | f x ≤ g x}, max (f x) (g x) ∂μ + ∫⁻ (x : α) in {x | f x ≤ g x}ᶜ, max (f x) (g x) ∂μ =
    ∫⁻ (x : α) in {x | f x ≤ g x}, g x ∂μ + ∫⁻ (x : α) in {a | f a ≤ g a}ᶜ, f x ∂μ
Module: Mathlib.MeasureTheory.Function.StronglyMeasurable.Basic

Goal state before:
pp: case neg
α : Type u_1
β : Type u_2
f g : α → β
m : MeasurableSpace α
inst✝ : TopologicalSpace β
s : Set α
x✝ : DecidablePred fun x ↦ x ∈ s
hs : MeasurableSet s
hf : StronglyMeasurable f
hg : StronglyMeasurable g
x : α
hx : x ∉ s
⊢ Tendsto (fun n ↦ ((fun n ↦ SimpleFunc.piecewise s hs (hf.approx n) (hg.approx n)) n) x) atTop (𝓝 (s.piecewise f g x))

Tactic:
simpa [@Set.piecewise_eq_of_notMem _ _ _ _ _ (fun _ => Classical.propDecidable _) _ hx,
      hx] using hg.tendsto_approx x

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 : MeasurableSet s
hs_subset : s ⊆ (μ.sigmaFiniteSetWRT' ν)ᶜ
hνs : ν s ≠ 0
⊢ μ s = ∞

Tactic:
suffices ¬ SigmaFinite (μ.restrict s) by
    by_contra h
    have h_lt_top : Fact (μ s < ∞) := ⟨Ne.lt_top h⟩
    exact this inferInstance

Goal state after:
α : Type u_1
mα : MeasurableSpace α
μ ν : Measure α
s : Set α
inst✝ : IsFiniteMeasure ν
hs : MeasurableSet s
hs_subset : s ⊆ (μ.sigmaFiniteSetWRT' ν)ᶜ
hνs : ν s ≠ 0
⊢ ¬SigmaFinite (μ.restrict s)
Module: Mathlib.MeasureTheory.Measure.Decomposition.Exhaustion

Goal state before:
pp: α : Type u_1
mα : MeasurableSpace α
μ ν : Measure α
hμν : μ ≪ ν
inst✝¹ : SigmaFinite μ
inst✝ : SFinite ν
h : ν (μ.sigmaFiniteSetWRT ν)ᶜ ≠ 0 → μ (μ.sigmaFiniteSetWRT ν)ᶜ = ∞
h0 : ¬ν (μ.sigmaFiniteSetWRT ν)ᶜ = 0
⊢ ⨆ i, (μ.restrict (spanningSets μ i)) (μ.sigmaFiniteSetWRT ν)ᶜ = 0

Tactic:
Measure.restrict_apply' (measurableSet_spanningSets μ _),

Goal state after:
α : Type u_1
mα : MeasurableSpace α
μ ν : Measure α
hμν : μ ≪ ν
inst✝¹ : SigmaFinite μ
inst✝ : SFinite ν
h : ν (μ.sigmaFiniteSetWRT ν)ᶜ ≠ 0 → μ (μ.sigmaFiniteSetWRT ν)ᶜ = ∞
h0 : ¬ν (μ.sigmaFiniteSetWRT ν)ᶜ = 0
⊢ ⨆ i, μ ((μ.sigmaFiniteSetWRT ν)ᶜ ∩ spanningSets μ i) = 0
Module: Mathlib.MeasureTheory.Integral.Lebesgue.DominatedConvergence

Goal state before:
pp: α : Type u_2
mα : MeasurableSpace α
f : ℕ → α → ℝ≥0∞
F : α → ℝ≥0∞
μ : Measure α
hf_meas : ∀ (n : ℕ), AEMeasurable (f n) μ
hF_meas : AEMeasurable F μ
hf_tendsto : Tendsto (fun i ↦ ∫⁻ (a : α), f i a ∂μ) atTop (𝓝 (∫⁻ (a : α), F a ∂μ))
hf_mono : ∀ᵐ (a : α) ∂μ, Monotone fun i ↦ f i a
h_bound : ∀ᵐ (a : α) ∂μ, ∀ (i : ℕ), f i a ≤ F a
h_int_finite : ∫⁻ (a : α), F a ∂μ ≠ ∞
h_bound_finite : ∀ᵐ (a : α) ∂μ, F a ≠ ∞
h_exists : ∀ᵐ (a : α) ∂μ, ∃ l, Tendsto (fun i ↦ f i a) atTop (𝓝 l)
F' : α → ℝ≥0∞ := fun a ↦ if h : ∃ l, Tendsto (fun i ↦ f i a) atTop (𝓝 l) then h.choose else ∞
hF'_tendsto : ∀ᵐ (a : α) ∂μ, Tendsto (fun i ↦ f i a) atTop (𝓝 (F' a))
⊢ ∀ᵐ (a : α) ∂μ, Tendsto (fun i ↦ f i a) atTop (𝓝 (F a))

Tactic:
suffices F' =ᵐ[μ] F by
    filter_upwards [this, hF'_tendsto] with a h_eq h_tendsto using h_eq ▸ h_tendsto

Goal state after:
α : Type u_2
mα : MeasurableSpace α
f : ℕ → α → ℝ≥0∞
F : α → ℝ≥0∞
μ : Measure α
hf_meas : ∀ (n : ℕ), AEMeasurable (f n) μ
hF_meas : AEMeasurable F μ
hf_tendsto : Tendsto (fun i ↦ ∫⁻ (a : α), f i a ∂μ) atTop (𝓝 (∫⁻ (a : α), F a ∂μ))
hf_mono : ∀ᵐ (a : α) ∂μ, Monotone fun i ↦ f i a
h_bound : ∀ᵐ (a : α) ∂μ, ∀ (i : ℕ), f i a ≤ F a
h_int_finite : ∫⁻ (a : α), F a ∂μ ≠ ∞
h_bound_finite : ∀ᵐ (a : α) ∂μ, F a ≠ ∞
h_exists : ∀ᵐ (a : α) ∂μ, ∃ l, Tendsto (fun i ↦ f i a) atTop (𝓝 l)
F' : α → ℝ≥0∞ := fun a ↦ if h : ∃ l, Tendsto (fun i ↦ f i a) atTop (𝓝 l) then h.choose else ∞
hF'_tendsto : ∀ᵐ (a : α) ∂μ, Tendsto (fun i ↦ f i a) atTop (𝓝 (F' a))
⊢ F' =ᵐ[μ] F
Module: Mathlib.Topology.Perfect

Goal state before:
pp: case specialize_1
α : Type u_1
inst✝¹ : TopologicalSpace α
inst✝ : T1Space α
U : Set α
hu : U.Nontrivial
h :
  ∀ (t t' : Set α),
    IsClosed[inst✝¹] t →
      IsClosed[inst✝¹] t' → U ⊆ t ∪ t' → (U ∩ t).Nonempty → (U ∩ t').Nonempty → (U ∩ (t ∩ t')).Nonempty
x : α
hx : x ∈ U
⊢ U ⊆ {x} ∪ closure[inst✝¹] (U \ {x})

Tactic:
trans {x} ∪ (U \ {x})

Goal state after:
α : Type u_1
inst✝¹ : TopologicalSpace α
inst✝ : T1Space α
U : Set α
hu : U.Nontrivial
h :
  ∀ (t t' : Set α),
    IsClosed[inst✝¹] t →
      IsClosed[inst✝¹] t' → U ⊆ t ∪ t' → (U ∩ t).Nonempty → (U ∩ t').Nonempty → (U ∩ (t ∩ t')).Nonempty
x : α
hx : x ∈ U
⊢ U ⊆ {x} ∪ U \ {x}

α : Type u_1
inst✝¹ : TopologicalSpace α
inst✝ : T1Space α
U : Set α
hu : U.Nontrivial
h :
  ∀ (t t' : Set α),
    IsClosed[inst✝¹] t →
      IsClosed[inst✝¹] t' → U ⊆ t ∪ t' → (U ∩ t).Nonempty → (U ∩ t').Nonempty → (U ∩ (t ∩ t')).Nonempty
x : α
hx : x ∈ U
⊢ {x} ∪ U \ {x} ⊆ {x} ∪ closure[inst✝¹] (U \ {x})
Module: Mathlib.Topology.Perfect

Goal state before:
pp: case refine_2
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
⊢ Preperfect D

Tactic:
rw [preperfect_iff_nhds]
    intro x xD E xE
    have : ¬(E ∩ D).Countable := by
      intro h
      obtain ⟨U, hUb, xU, hU⟩ : ∃ U ∈ b, x ∈ U ∧ U ⊆ E :=
        (IsTopologicalBasis.mem_nhds_iff bbasis).mp xE
      have hU_cnt : (U ∩ C).Countable := by
        apply @Countable.mono _ _ (E ∩ D ∪ V ∩ C)
        · rintro y ⟨yU, yC⟩
          by_cases h : y ∈ V
          · exact mem_union_right _ (mem_inter h yC)
          · exact mem_union_left _ (mem_inter (hU yU) ⟨yC, h⟩)
        exact Countable.union h Vct
      have : U ∈ v := ⟨hUb, hU_cnt⟩
      apply xD.2
      exact mem_biUnion this xU
    by_contra! h
    exact absurd (Countable.mono h (Set.countable_singleton _)) this

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

Goal state before:
pp: α : Type u_2
mα : MeasurableSpace α
f : ℕ → α → ℝ≥0∞
F : α → ℝ≥0∞
μ : Measure α
hf_meas : ∀ (n : ℕ), AEMeasurable (f n) μ
hf_tendsto : Tendsto (fun i ↦ ∫⁻ (a : α), f i a ∂μ) atTop (𝓝 (∫⁻ (a : α), F a ∂μ))
hf_mono : ∀ᵐ (a : α) ∂μ, Antitone fun i ↦ f i a
h_bound : ∀ᵐ (a : α) ∂μ, ∀ (i : ℕ), F a ≤ f i a
h0 : ∫⁻ (a : α), f 0 a ∂μ ≠ ∞
h_int_finite : ∫⁻ (a : α), F a ∂μ ≠ ∞
h_exists : ∀ᵐ (a : α) ∂μ, ∃ l, Tendsto (fun i ↦ f i a) atTop (𝓝 l)
F' : α → ℝ≥0∞ := fun a ↦ if h : ∃ l, Tendsto (fun i ↦ f i a) atTop (𝓝 l) then h.choose else ∞
hF'_tendsto : ∀ᵐ (a : α) ∂μ, Tendsto (fun i ↦ f i a) atTop (𝓝 (F' a))
⊢ ∀ᵐ (a : α) ∂μ, Tendsto (fun i ↦ f i a) atTop (𝓝 (F a))

Tactic:
suffices F' =ᵐ[μ] F by
    filter_upwards [this, hF'_tendsto] with a h_eq h_tendsto using h_eq ▸ h_tendsto

Goal state after:
α : Type u_2
mα : MeasurableSpace α
f : ℕ → α → ℝ≥0∞
F : α → ℝ≥0∞
μ : Measure α
hf_meas : ∀ (n : ℕ), AEMeasurable (f n) μ
hf_tendsto : Tendsto (fun i ↦ ∫⁻ (a : α), f i a ∂μ) atTop (𝓝 (∫⁻ (a : α), F a ∂μ))
hf_mono : ∀ᵐ (a : α) ∂μ, Antitone fun i ↦ f i a
h_bound : ∀ᵐ (a : α) ∂μ, ∀ (i : ℕ), F a ≤ f i a
h0 : ∫⁻ (a : α), f 0 a ∂μ ≠ ∞
h_int_finite : ∫⁻ (a : α), F a ∂μ ≠ ∞
h_exists : ∀ᵐ (a : α) ∂μ, ∃ l, Tendsto (fun i ↦ f i a) atTop (𝓝 l)
F' : α → ℝ≥0∞ := fun a ↦ if h : ∃ l, Tendsto (fun i ↦ f i a) atTop (𝓝 l) then h.choose else ∞
hF'_tendsto : ∀ᵐ (a : α) ∂μ, Tendsto (fun i ↦ f i a) atTop (𝓝 (F' a))
⊢ F' =ᵐ[μ] F
Module: Mathlib.Topology.MetricSpace.CantorScheme

Goal state before:
pp: β : Type u_1
α : Type u_2
A : List β → Set α
hA : CantorScheme.Disjoint A
x y : ↑(inducedMap A).fst
hxy : (inducedMap A).snd x = (inducedMap A).snd y
n : ℕ
⊢ res (↑x) n = res (↑y) n

Tactic:
induction n with
  | zero => simp
  | succ n ih =>
    simp only [res_succ, cons.injEq]
    refine ⟨?_, ih⟩
    contrapose hA
    simp only [CantorScheme.Disjoint, _root_.Pairwise, Ne, not_forall, exists_prop]
    refine ⟨res x n, _, _, hA, ?_⟩
    rw [not_disjoint_iff]
    refine ⟨(inducedMap A).2 x, ?_, ?_⟩
    · rw [← res_succ]
      apply map_mem
    rw [hxy, ih, ← res_succ]
    apply map_mem

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

Goal state before:
pp: case a
E✝ : ℕ → Type u_1
inst✝² : (n : ℕ) → TopologicalSpace (E✝ n)
inst✝¹ : ∀ (n : ℕ), DiscreteTopology (E✝ n)
E : ℕ → Type u_2
inst✝ : (n : ℕ) → UniformSpace (E n)
h : ∀ (n : ℕ), uniformity (E n) = 𝓟 SetRel.id
this : ∀ (n : ℕ), DiscreteTopology (E n)
ε : ℝ
εpos : ε > 0
n : ℕ
hn : (1 / 2) ^ n < ε
⊢ {p | dist p.1 p.2 < ε} ∈ ⨅ i, 𝓟 {a | a.1 i = a.2 i}

Tactic:
apply
          @mem_iInf_of_iInter _ _ _ _ _ (Finset.range n).finite_toSet fun i =>
            { p : (∀ n : ℕ, E n) × ∀ n : ℕ, E n | p.fst i = p.snd i }

Goal state after:
case a.hV
E✝ : ℕ → Type u_1
inst✝² : (n : ℕ) → TopologicalSpace (E✝ n)
inst✝¹ : ∀ (n : ℕ), DiscreteTopology (E✝ n)
E : ℕ → Type u_2
inst✝ : (n : ℕ) → UniformSpace (E n)
h : ∀ (n : ℕ), uniformity (E n) = 𝓟 SetRel.id
this : ∀ (n : ℕ), DiscreteTopology (E n)
ε : ℝ
εpos : ε > 0
n : ℕ
hn : (1 / 2) ^ n < ε
⊢ ∀ (i : ↑↑(Finset.range n)), {p | p.1 ↑i = p.2 ↑i} ∈ 𝓟 {a | a.1 ↑i = a.2 ↑i}

case a.hU
E✝ : ℕ → Type u_1
inst✝² : (n : ℕ) → TopologicalSpace (E✝ n)
inst✝¹ : ∀ (n : ℕ), DiscreteTopology (E✝ n)
E : ℕ → Type u_2
inst✝ : (n : ℕ) → UniformSpace (E n)
h : ∀ (n : ℕ), uniformity (E n) = 𝓟 SetRel.id
this : ∀ (n : ℕ), DiscreteTopology (E n)
ε : ℝ
εpos : ε > 0
n : ℕ
hn : (1 / 2) ^ n < ε
⊢ ⋂ i, {p | p.1 ↑i = p.2 ↑i} ⊆ {p | dist p.1 p.2 < ε}
Module: Mathlib.Topology.MetricSpace.PiNat

Goal state before:
pp: E✝ : ℕ → Type u_1
inst✝² : (n : ℕ) → TopologicalSpace (E✝ n)
inst✝¹ : ∀ (n : ℕ), DiscreteTopology (E✝ n)
E : ℕ → Type u_2
inst✝ : (n : ℕ) → UniformSpace (E n)
h : ∀ (n : ℕ), uniformity (E n) = 𝓟 SetRel.id
this : ∀ (n : ℕ), DiscreteTopology (E n)
ε : ℝ
εpos : ε > 0
n : ℕ
hn : (1 / 2) ^ n < ε
x y : (n : ℕ) → E n
hxy : ∀ i < n, x i = y i
⊢ dist (x, y).1 (x, y).2 ≤ (1 / 2) ^ n

Tactic:
← mem_cylinder_iff_dist_le,

Goal state after:
E✝ : ℕ → Type u_1
inst✝² : (n : ℕ) → TopologicalSpace (E✝ n)
inst✝¹ : ∀ (n : ℕ), DiscreteTopology (E✝ n)
E : ℕ → Type u_2
inst✝ : (n : ℕ) → UniformSpace (E n)
h : ∀ (n : ℕ), uniformity (E n) = 𝓟 SetRel.id
this : ∀ (n : ℕ), DiscreteTopology (E n)
ε : ℝ
εpos : ε > 0
n : ℕ
hn : (1 / 2) ^ n < ε
x y : (n : ℕ) → E n
hxy : ∀ i < n, x i = y i
⊢ (x, y).1 ∈ cylinder (x, y).2 n
Module: Mathlib.Topology.MetricSpace.PiNat

Goal state before:
pp: case neg
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 : IsClosed[Pi.topologicalSpace] s
hne : s.Nonempty
f : ((n : ℕ) → E n) → (n : ℕ) → E n := fun x ↦ if x ∈ s then x else ⋯.some
fs : ∀ x ∈ s, f x = x
x y : (n : ℕ) → E n
hxy : x ≠ y
hfxfy : x ≠ f y
I2 : cylinder x (firstDiff x y) = cylinder y (firstDiff x y)
xs : x ∈ s
ys : y ∉ s
A : (s ∩ cylinder y (longestPrefix y s)).Nonempty
fy : f y = A.some
⊢ firstDiff x y ≤ firstDiff x (f y)

Tactic:
have I : cylinder A.some (firstDiff x y) = cylinder y (firstDiff x y) := by
        rw [← mem_cylinder_iff_eq, firstDiff_comm]
        apply cylinder_anti y _ A.some_mem.2
        exact firstDiff_le_longestPrefix hs ys xs

Goal state after:
case neg
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 : IsClosed[Pi.topologicalSpace] s
hne : s.Nonempty
f : ((n : ℕ) → E n) → (n : ℕ) → E n := fun x ↦ if x ∈ s then x else ⋯.some
fs : ∀ x ∈ s, f x = x
x y : (n : ℕ) → E n
hxy : x ≠ y
hfxfy : x ≠ f y
I2 : cylinder x (firstDiff x y) = cylinder y (firstDiff x y)
xs : x ∈ s
ys : y ∉ s
A : (s ∩ cylinder y (longestPrefix y s)).Nonempty
fy : f y = A.some
I : cylinder A.some (firstDiff x y) = cylinder y (firstDiff x y)
⊢ firstDiff x y ≤ firstDiff x (f y)
Module: Mathlib.MeasureTheory.Measure.MutuallySingular

Goal state before:
pp: α : Type u_1
m0 : MeasurableSpace α
μ ν₁ ν₂ : Measure α
h : μ ≪ ν₁ + ν₂
h_ms : μ ⟂ₘ ν₂
s : Set α
hs : MeasurableSet s
hs_zero : ν₁ s = 0
⊢ μ s = 0

Tactic:
let t := h_ms.nullSet

Goal state after:
α : Type u_1
m0 : MeasurableSpace α
μ ν₁ ν₂ : Measure α
h : μ ≪ ν₁ + ν₂
h_ms : μ ⟂ₘ ν₂
s : Set α
hs : MeasurableSet s
hs_zero : ν₁ s = 0
t : Set α := h_ms.nullSet
⊢ μ s = 0
Module: Mathlib.MeasureTheory.Measure.MutuallySingular

Goal state before:
pp: α : Type u_1
m0 : MeasurableSpace α
μ ν : Measure α
h : Disjoint μ ν
ε : ℝ≥0
hε : 0 < ε
h₁ : sInf {m | ∃ t, m = μ t + ν tᶜ} = 0
n : ℕ
⊢ ¬ε = 0

Tactic:
exact hε.ne.symm

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

Goal state before:
pp: α : Type u_1
inst✝ : MeasurableSpace α
s : Set α
a : α
⊢ (toMeasurable (dirac a) s).indicator 1 a = 0 ∨ (toMeasurable (dirac a) s).indicator 1 a = 1

Tactic:
indicator

Goal state after:
α : Type u_1
inst✝ : MeasurableSpace α
s : Set α
a : α
⊢ (if a ∈ toMeasurable (dirac a) s then 1 a else 0) = 0 ∨ (if a ∈ toMeasurable (dirac a) s then 1 a else 0) = 1
Module: Mathlib.MeasureTheory.Measure.Count

Goal state before:
pp: case neg
α : Type u_1
inst✝ : MeasurableSpace α
s : Set α
s_mble : MeasurableSet s
hs : ¬s.Finite
⊢ count s = ∞ ↔ s.Infinite

Tactic:
change s.Infinite at hs

Goal state after:
case neg
α : Type u_1
inst✝ : MeasurableSpace α
s : Set α
s_mble : MeasurableSet s
hs : s.Infinite
⊢ count s = ∞ ↔ s.Infinite
Module: Mathlib.MeasureTheory.Measure.Count

Goal state before:
pp: case neg
α : Type u_1
inst✝¹ : MeasurableSpace α
s : Set α
inst✝ : MeasurableSingletonClass α
hs : ¬s.Finite
⊢ count s = ∞ ↔ s.Infinite

Tactic:
change s.Infinite at hs

Goal state after:
case neg
α : Type u_1
inst✝¹ : MeasurableSpace α
s : Set α
inst✝ : MeasurableSingletonClass α
hs : s.Infinite
⊢ count s = ∞ ↔ s.Infinite
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)
s : Set ((n : ℕ) → E n)
hs : IsClosed[Pi.topologicalSpace] s
hne : s.Nonempty
⊢ ∃ f, (∀ (x : ↑s), f ↑x = x) ∧ Surjective f ∧ Continuous[Pi.topologicalSpace, instTopologicalSpaceSubtype] f

Tactic:
obtain ⟨f, fs, rfl, f_cont⟩ :
    ∃ f : (∀ n, E n) → ∀ n, E n, (∀ x ∈ s, f x = x) ∧ range f = s ∧ Continuous f :=
    exists_retraction_of_isClosed hs hne
  have A : ∀ x : range f, rangeFactorization f x = x := fun x ↦ Subtype.ext <| fs x x.2
  exact ⟨rangeFactorization f, A, fun x => ⟨x, A x⟩, f_cont.subtype_mk _⟩

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

Goal state before:
pp: α : Type u_1
β : Type u_2
mα : MeasurableSpace α
mβ : MeasurableSpace β
f : β → Measure α
h : ∀ (s : Set α), MeasurableSet s → Measurable fun b ↦ (f b) s
s : Set α
hs : MeasurableSet s
⊢ borel ℝ≥0∞ ≤ MeasurableSpace.map (fun μ ↦ μ s) (MeasurableSpace.map f mβ)

Tactic:
MeasurableSpace.map_comp

Goal state after:
α : Type u_1
β : Type u_2
mα : MeasurableSpace α
mβ : MeasurableSpace β
f : β → Measure α
h : ∀ (s : Set α), MeasurableSet s → Measurable fun b ↦ (f b) s
s : Set α
hs : MeasurableSet s
⊢ borel ℝ≥0∞ ≤ MeasurableSpace.map ((fun μ ↦ μ s) ∘ f) mβ
Module: Mathlib.MeasureTheory.Integral.Lebesgue.Countable

Goal state before:
pp: case hfg
α : Type u_1
inst✝¹ : MeasurableSpace α
μ✝ : Measure α
f : α → ℝ≥0∞
μ : Measure α
inst✝ : SFinite μ
h : IsFiniteMeasure μ
g : ℕ → α → ℝ≥0∞
hgm : ∀ (n : ℕ), Measurable (g n)
hgf : ∀ (n : ℕ), g n ≤ f
hgle : ∀ (n : ℕ), g n ≤ ↑n
hgint : ∀ (n : ℕ), ∫⁻ (a : α), min (f a) ↑n ∂μ = ∫⁻ (a : α), g n a ∂μ
φ : α → ℝ≥0∞ := fun x ↦ ⨆ n, g n x
hφm : Measurable φ
hφle : φ ≤ f
s : Set α
ψ : SimpleFunc α ℝ≥0
hψ : ∀ (x : α), ↑(ψ x) ≤ f x
n : ℕ
hn : ∀ (x : α), ψ x ≤ ↑n
this : ∫⁻ (a : α) in (toMeasurable μ s)ᶜ, min (f a) ↑n ∂μ ≠ ∞
hsm : MeasurableSet (toMeasurable μ s)
x : α
⊢ g n x ≤ min (f x) ↑n

Tactic:
exact le_min (hgf n x) (hgle n x)

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

Goal state before:
pp: X : Type u_1
Y : Type u_2
inst✝³ : TopologicalSpace X
m : MeasurableSpace X
inst✝² : TopologicalSpace Y
inst✝¹ : T2Space Y
μ : Measure X
inst✝ : μ.IsOpenPosMeasure
U : Set X
f g : X → Y
hU : IsOpen[inst✝³] U
hf : ContinuousOn f U
hg : ContinuousOn g U
h : μ {a | a ∈ U ∧ ¬f a = g a} = 0
this : U ∩ {a | f a ≠ g a} ⊆ ∅
⊢ EqOn f g U

Tactic:
exact fun x hx => Classical.not_not.1 fun h => this ⟨hx, h⟩

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

Goal state before:
pp: case refine_3
α : Type u_1
β : Type u_2
inst✝² : MeasurableSpace α
inst✝¹ : MeasurableSpace β
ν : Measure β
inst✝ : SFinite ν
m : ∀ {α : Type u_1} {β : Type u_2} {m : MeasurableSpace α} {mβ : MeasurableSpace β} {x : α}, Measurable (Prod.mk x)
f : ℕ → α × β → ℝ≥0∞
hf : ∀ (n : ℕ), Measurable (f n)
h2f : Monotone f
h3f : ∀ (n : ℕ), Measurable fun x ↦ ∫⁻ (y : β), f n (x, y) ∂ν
this : ∀ (x : α), Monotone fun n y ↦ f n (x, y)
⊢ Measurable fun x ↦ ∫⁻ (y : β), (fun x ↦ ⨆ n, f n x) (x, y) ∂ν

Tactic:
conv => enter [1, x]; erw [lintegral_iSup (fun n => (hf n).comp m) (this x)]

Goal state after:
case refine_3
α : Type u_1
β : Type u_2
inst✝² : MeasurableSpace α
inst✝¹ : MeasurableSpace β
ν : Measure β
inst✝ : SFinite ν
m : ∀ {α : Type u_1} {β : Type u_2} {m : MeasurableSpace α} {mβ : MeasurableSpace β} {x : α}, Measurable (Prod.mk x)
f : ℕ → α × β → ℝ≥0∞
hf : ∀ (n : ℕ), Measurable (f n)
h2f : Monotone f
h3f : ∀ (n : ℕ), Measurable fun x ↦ ∫⁻ (y : β), f n (x, y) ∂ν
this : ∀ (x : α), Monotone fun n y ↦ f n (x, y)
⊢ Measurable fun x ↦ ⨆ n, ∫⁻ (a : β), (f n ∘ Prod.mk x) a ∂ν
Module: Mathlib.GroupTheory.Complement

Goal state before:
pp: G : Type u_1
inst✝ : Group G
H K : Subgroup G
h : H.IsComplement' K
⊢ K.IsComplement' H

Tactic:
let ϕ : H × K ≃ K × H :=
    Equiv.mk (fun x => ⟨x.2⁻¹, x.1⁻¹⟩) (fun x => ⟨x.2⁻¹, x.1⁻¹⟩)
      (fun x => Prod.ext (inv_inv _) (inv_inv _)) fun x => Prod.ext (inv_inv _) (inv_inv _)
  let ψ : G ≃ G := Equiv.mk (fun g : G => g⁻¹) (fun g : G => g⁻¹) inv_inv inv_inv
  suffices hf : (ψ ∘ fun x : H × K => x.1.1 * x.2.1) = (fun x : K × H => x.1.1 * x.2.1) ∘ ϕ by
    rwa [isComplement'_def, isComplement_iff_bijective, ← Equiv.bijective_comp ϕ, ← hf,
      ψ.comp_bijective]
  exact funext fun x => mul_inv_rev _ _

Goal state after: