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

Goal state before:
pp: case pos.mp
X : Type u_1
inst✝² : LinearOrder X
inst✝¹ : TopologicalSpace X
inst✝ : OrderTopology X
s : Set X
b : X
hsne : s.Nonempty
this : Nonempty ↑s
hsub : s ⊆ Iio b
⊢ comap Subtype.val (𝓝[<] b) = atTop → ∀ a < b, (s ∩ Ioo a b).Nonempty

Tactic:
intro h a ha

Goal state after:
case pos.mp
X : Type u_1
inst✝² : LinearOrder X
inst✝¹ : TopologicalSpace X
inst✝ : OrderTopology X
s : Set X
b : X
hsne : s.Nonempty
this : Nonempty ↑s
hsub : s ⊆ Iio b
h : comap Subtype.val (𝓝[<] b) = atTop
a : X
ha : a < b
⊢ (s ∩ Ioo a b).Nonempty
Module: Mathlib.MeasureTheory.Measure.Typeclasses.Finite

Goal state before:
pp: α : Type u_1
β : Type u_2
δ : Type u_3
ι : Type u_4
m0 : MeasurableSpace α
mβ : MeasurableSpace β
μ✝ ν ν₁ ν₂ : Measure α
s✝ t : Set α
s : Finset ι
μ : ι → Measure α
inst✝ : ∀ (i : ι), IsFiniteMeasure (μ i)
⊢ (∑ i ∈ s, μ i) univ < ∞

Tactic:
by simp [measure_lt_top]

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

Goal state before:
pp: α : Type u_1
m0 : MeasurableSpace α
inst✝¹ : TopologicalSpace α
μ : Measure α
inst✝ : IsLocallyFiniteMeasure μ
x : α
s : Set α
⊢ x ∈ s → IsOpen[inst✝¹] s → ∃ v ∈ {s | IsOpen[inst✝¹] s ∧ μ s < ∞}, x ∈ v ∧ v ⊆ s

Tactic:
xs

Goal state after:
α : Type u_1
m0 : MeasurableSpace α
inst✝¹ : TopologicalSpace α
μ : Measure α
inst✝ : IsLocallyFiniteMeasure μ
x : α
s : Set α
xs : x ∈ s
⊢ IsOpen[inst✝¹] s → ∃ v ∈ {s | IsOpen[inst✝¹] s ∧ μ s < ∞}, x ∈ v ∧ v ⊆ s
Module: Mathlib.MeasureTheory.Measure.Typeclasses.SFinite

Goal state before:
pp: case neg
α : Type u_1
m0 : MeasurableSpace α
μ : Measure α
s : Set α
hs : MeasurableSet s
t : Set α
m : ℕ → Measure α
hv : ∀ (n : ℕ), (m n) t ≠ ∞
hμ : μ = sum m
A : ∃ t' ⊇ t, MeasurableSet t' ∧ ∀ (u : Set α), MeasurableSet u → μ (t' ∩ u) = μ (t ∩ u)
ht : ¬∃ t_1 ⊇ t, MeasurableSet t_1 ∧ t_1 =ᵐ[μ] t
⊢ μ (A.choose ∩ s) = μ (t ∩ s)

Tactic:
· exact A.choose_spec.2.2 s hs

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

Goal state before:
pp: case e_f
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)
hw : ∀ (n : ℕ), μ (w n) < ∞
t' : Set α := ⋃ n, toMeasurable μ (t ∩ disjointed w n)
ht' : t' = ⋃ n, toMeasurable μ (t ∩ disjointed w n)
tt' : t ⊆ t'
u : Set α
hu : MeasurableSet u
n : ℕ
⊢ μ (disjointed w n ∩ t ∩ u) = μ (disjointed w n ∩ (t ∩ u))

pp: case e_f
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)
hw : ∀ (n : ℕ), μ (w n) < ∞
t' : Set α := ⋃ n, toMeasurable μ (t ∩ disjointed w n)
ht' : t' = ⋃ n, toMeasurable μ (t ∩ disjointed w n)
tt' : t ⊆ t'
u : Set α
hu : MeasurableSet u
n : ℕ
⊢ MeasurableSet (disjointed w n)

Tactic:
inter_assoc

Goal state after:
case e_f
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)
hw : ∀ (n : ℕ), μ (w n) < ∞
t' : Set α := ⋃ n, toMeasurable μ (t ∩ disjointed w n)
ht' : t' = ⋃ n, toMeasurable μ (t ∩ disjointed w n)
tt' : t ⊆ t'
u : Set α
hu : MeasurableSet u
n : ℕ
⊢ μ (disjointed w n ∩ (t ∩ u)) = μ (disjointed w n ∩ (t ∩ u))

case e_f
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)
hw : ∀ (n : ℕ), μ (w n) < ∞
t' : Set α := ⋃ n, toMeasurable μ (t ∩ disjointed w n)
ht' : t' = ⋃ n, toMeasurable μ (t ∩ disjointed w n)
tt' : t ⊆ t'
u : Set α
hu : MeasurableSet u
n : ℕ
⊢ MeasurableSet (disjointed w n)
Module: Mathlib.MeasureTheory.Measure.Restrict

Goal state before:
pp: case refine_2
α : Type u_2
m0 : MeasurableSpace α
μ : Measure α
β : Type u_7
inst✝ : Group β
f g : α → β
h : f =ᵐ[μ] g
x : α
hx : f x = g x
⊢ (f / g) x = 1 x

Tactic:
rwa [Pi.div_apply, Pi.one_apply, div_eq_one]

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

Goal state before:
pp: case neg
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) ≠ ∞
A : ∃ t' ⊇ t, MeasurableSet t' ∧ ∀ (u : Set α), MeasurableSet u → μ (t' ∩ u) = μ (t ∩ u)
ht : ¬∃ t_1 ⊇ t, MeasurableSet t_1 ∧ t_1 =ᵐ[μ] t
⊢ μ (A.choose ∩ s) = μ (t ∩ s)

Tactic:
· exact A.choose_spec.2.2 s hs

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

Goal state before:
pp: δ : Type u_4
u : Set δ
inst✝ : MeasureSpace δ
hu : NullMeasurableSet u volume
⊢ volume (Subtype.val '' univ) = volume u

Tactic:
simp only [image_univ, Subtype.range_coe_subtype, ofPred_mem_eq]

Goal state after:
Module: Mathlib.MeasureTheory.MeasurableSpace.CountablyGenerated

Goal state before:
pp: case refine_1.refine_2
α : Type u_1
mα : MeasurableSpace α
inst✝ : CountablyGenerated α
s : Set α
hs : MeasurableSet s
n : ℕ
x✝ : MeasurableSet (natGeneratingSequence α n)
x : α
p : ℕ → Prop
hpn : p n
hpx : x ∈ if p n then natGeneratingSequence α n else (natGeneratingSequence α n)ᶜ
⊢ x ∈ natGeneratingSequence α n

Tactic:
simpa [hpn] using hpx

Goal state after:
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) ∩ ((fun x ↦ 0) ⁻¹' t \ s)ᶜ) = 0 ↔ μ ((f ⁻¹' t)ᶜ ∩ s) = 0

Tactic:
simp only [ht, ← Set.compl_eq_univ_sdiff, compl_compl, if_true,
    Set.preimage_const]

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
inst✝ : MeasurableSpace α
s : Set α
⊢ CountablySeparated ↑s ↔ HasCountableSeparatingOn α MeasurableSet s

Tactic:
by
  rw [countablySeparated_def]
  exact HasCountableSeparatingOn.subtype_iff

Goal state after:
Module: Mathlib.MeasureTheory.MeasurableSpace.CountablyGenerated

Goal state before:
pp: α : Type u_1
inst✝² : MeasurableSpace α
inst✝¹ : CountablyGenerated α
inst✝ : SeparatesPoints α
⊢ ∃ s, Nonempty (α ≃ᵐ ↑s)

Tactic:
use range (mapNatBool α), Equiv.ofInjective _ <|
    injective_mapNatBool _,
    Measurable.subtype_mk <| measurable_mapNatBool _
  simp_rw +instances [← generateFrom_natGeneratingSequence α]
  apply measurable_generateFrom
  rintro _ ⟨n, rfl⟩
  rw [← Equiv.image_eq_preimage_symm _ _]
  refine ⟨{y | y n}, by measurability, ?_⟩
  rw [← Equiv.preimage_eq_iff_eq_image]
  simp [mapNatBool]

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

Goal state before:
pp: ι : Type u_1
α : Type u_2
β : Type u_3
m0 : MeasurableSpace α
inst✝¹ : MeasurableSpace β
f : α → β
inst✝ : Countable ι
μ : ι → Measure α
h : ∀ (i : ι), AEMeasurable f (μ i)
a✝ : Nontrivial β
inhabited_h : Inhabited β
s : ι → Set α := fun i ↦ toMeasurable (μ i) {x | f x ≠ mk f ⋯ x}
⊢ AEMeasurable f (sum μ)

Tactic:
have hsμ : ∀ i, μ i (s i) = 0 := by
    intro i
    rw [measure_toMeasurable]
    exact (h i).ae_eq_mk

Goal state after:
ι : Type u_1
α : Type u_2
β : Type u_3
m0 : MeasurableSpace α
inst✝¹ : MeasurableSpace β
f : α → β
inst✝ : Countable ι
μ : ι → Measure α
h : ∀ (i : ι), AEMeasurable f (μ i)
a✝ : Nontrivial β
inhabited_h : Inhabited β
s : ι → Set α := fun i ↦ toMeasurable (μ i) {x | f x ≠ mk f ⋯ x}
hsμ : ∀ (i : ι), (μ i) (s i) = 0
⊢ AEMeasurable f (sum μ)
Module: Mathlib.Topology.MetricSpace.HausdorffDistance

Goal state before:
pp: α : Type u
inst✝ : PseudoEMetricSpace α
x y : α
⊢ max (infEDist x {y}) (infEDist y {x}) = edist x y

Tactic:
infEDist_singleton

Goal state after:
α : Type u
inst✝ : PseudoEMetricSpace α
x y : α
⊢ max (edist x y) (edist y x) = edist x y
Module: Mathlib.Topology.MetricSpace.HausdorffDistance

Goal state before:
pp: case H1
α : Type u
inst✝ : PseudoMetricSpace α
s t : Set α
bs : Bornology.IsBounded s
bt : Bornology.IsBounded t
cs : α
hcs : cs ∈ s
ct : α
hct : ct ∈ t
rs : ℝ
hrs : s ⊆ closedBall ct rs
rt : ℝ
hrt : t ⊆ closedBall cs rt
x : α
⊢ x ∈ s → ∃ y ∈ t, edist x y ≤ ENNReal.ofReal (max rs rt)

Tactic:
xs

Goal state after:
case H1
α : Type u
inst✝ : PseudoMetricSpace α
s t : Set α
bs : Bornology.IsBounded s
bt : Bornology.IsBounded t
cs : α
hcs : cs ∈ s
ct : α
hct : ct ∈ t
rs : ℝ
hrs : s ⊆ closedBall ct rs
rt : ℝ
hrt : t ⊆ closedBall cs rt
x : α
xs : x ∈ s
⊢ ∃ y ∈ t, edist x y ≤ ENNReal.ofReal (max rs rt)
Module: Mathlib.Topology.MetricSpace.HausdorffDistance

Goal state before:
pp: case H1
α : Type u
inst✝ : PseudoMetricSpace α
s t : Set α
r : ℝ
hr : 0 ≤ r
H1 : ∀ x ∈ s, ∃ y ∈ t, dist x y ≤ r
H2 : ∀ x ∈ t, ∃ y ∈ s, dist x y ≤ r
x : α
⊢ x ∈ s → infDist x t ≤ r

Tactic:
xs

Goal state after:
case H1
α : Type u
inst✝ : PseudoMetricSpace α
s t : Set α
r : ℝ
hr : 0 ≤ r
H1 : ∀ x ∈ s, ∃ y ∈ t, dist x y ≤ r
H2 : ∀ x ∈ t, ∃ y ∈ s, dist x y ≤ r
x : α
xs : x ∈ s
⊢ infDist x t ≤ r
Module: Mathlib.MeasureTheory.Function.SimpleFunc

Goal state before:
pp: α : Type u_1
β : Type u_2
γ : Type u_3
inst✝² : MeasurableSpace α
inst✝¹ : Zero β
inst✝ : Zero γ
g : β → γ
hg : g 0 = 0
f : α →ₛ β
s : Set α
x : α
hs : MeasurableSet s
⊢ (map g (f.restrict s)) x = ((map g f).restrict s) x

Tactic:
simp [hs, Set.indicator_comp_of_zero hg]

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

Goal state before:
pp: case pos
α : Type u_1
inst✝⁴ : TopologicalSpace α
mα : MeasurableSpace α
inst✝³ : BorelSpace α
inst✝² : LinearOrder α
inst✝¹ : OrderTopology α
inst✝ : SecondCountableTopology α
s : Set α
h : ∀ x ∈ s, s ∈ 𝓝[>] x
x₀ : α
x₀s : x₀ ∈ s
h₀ : IsTop x₀
⊢ MeasurableSet s

Tactic:
have : s = { x₀ } ∪ s \ { x₀ } := by rw [union_sdiff_cancel (singleton_subset_iff.2 x₀s)]

Goal state after:
case pos
α : Type u_1
inst✝⁴ : TopologicalSpace α
mα : MeasurableSpace α
inst✝³ : BorelSpace α
inst✝² : LinearOrder α
inst✝¹ : OrderTopology α
inst✝ : SecondCountableTopology α
s : Set α
h : ∀ x ∈ s, s ∈ 𝓝[>] x
x₀ : α
x₀s : x₀ ∈ s
h₀ : IsTop x₀
this : s = {x₀} ∪ s \ {x₀}
⊢ MeasurableSet s
Module: Mathlib.MeasureTheory.Function.SimpleFunc

Goal state before:
pp: α : Type u_1
m : MeasurableSpace α
μ : Measure α
f : α →ₛ ℝ≥0∞
s : Set α
hs : MeasurableSet s
b : α
hb : f b = 0
⊢ f b * μ (⇑(f.restrict s) ⁻¹' {f b}) = f b * μ (⇑f ⁻¹' {f b} ∩ s)

Tactic:
by simp only [hb, zero_mul]

Goal state after:
Module: Mathlib.Topology.Instances.Real.Lemmas

Goal state before:
pp: x ε : ℝ
⊢ TotallyBounded (ball x ε)

Tactic:
rw [Real.ball_eq_Ioo]

Goal state after:
x ε : ℝ
⊢ TotallyBounded (Ioo (x - ε) (x + ε))
Module: Mathlib.Topology.Instances.Real.Lemmas

Goal state before:
pp: K : Subfield ℝ
hc : IsClosed ↑K
⊢ closure ↑K = univ

Tactic:
refine Rat.denseRange_cast.mono ?_ |>.closure_eq

Goal state after:
K : Subfield ℝ
hc : IsClosed ↑K
⊢ range Rat.cast ⊆ ↑K
Module: Mathlib.MeasureTheory.Function.SimpleFuncDense

Goal state before:
pp: case succ
α : Type u_1
inst✝² : MeasurableSpace α
inst✝¹ : PseudoEMetricSpace α
inst✝ : OpensMeasurableSpace α
e : ℕ → α
x : α
N : ℕ
ihN : ∀ {k : ℕ}, k ≤ N → edist ((nearestPt e N) x) x ≤ edist (e k) x
k : ℕ
hk : k ≤ N + 1
⊢ edist ((nearestPt e (N + 1)) x) x ≤ edist (e k) x

Tactic:
simp only [nearestPt, nearestPtInd_succ, map_apply]

Goal state after:
case succ
α : Type u_1
inst✝² : MeasurableSpace α
inst✝¹ : PseudoEMetricSpace α
inst✝ : OpensMeasurableSpace α
e : ℕ → α
x : α
N : ℕ
ihN : ∀ {k : ℕ}, k ≤ N → edist ((nearestPt e N) x) x ≤ edist (e k) x
k : ℕ
hk : k ≤ N + 1
⊢ edist (e (if ∀ k ≤ N, edist (e (N + 1)) x < edist (e k) x then N + 1 else (nearestPtInd e N) x)) x ≤ edist (e k) x
Module: Mathlib.MeasureTheory.Function.SimpleFuncDense

Goal state before:
pp: α : Type u_1
inst✝² : MeasurableSpace α
inst✝¹ : PseudoEMetricSpace α
inst✝ : OpensMeasurableSpace α
e : ℕ → α
x : α
k N : ℕ
hk : k ≤ N
⊢ edist ((nearestPt e N) x) x ≤ edist (e k) x

Tactic:
induction N generalizing k with

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

Goal state before:
pp: case right
μ : Measure ℝ
inst✝¹ : IsFiniteMeasureOnCompacts μ
inst✝ : NullSingletonClass μ
b : ℝ
⊢ Tendsto (fun δ ↦ μ (Icc (b - δ) (b + δ))) (𝓝[≥] 0) (𝓝 0)

Tactic:
simpa only [measure_singleton] using tendsto_measure_Icc_nhdsWithin_right μ b

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

Goal state before:
pp: α : Type u_1
β : Type u_2
inst✝ : TopologicalSpace β
m₀ : MeasurableSpace α
μ : Measure α
f : α → β
hf : AEStronglyMeasurable f μ
⊢ ∃ t, IsSeparable t ∧ ∀ᵐ (x : α) ∂μ, f x ∈ t

Tactic:
refine ⟨range (hf.mk f), hf.stronglyMeasurable_mk.isSeparable_range, ?_⟩
  filter_upwards [hf.ae_eq_mk] with x hx
  simp [hx]

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

Goal state before:
pp: case inr
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 : Set β
t_sep : IsSeparable t
ht : ∀ᵐ (x : α) ∂μ, f x ∈ t
h₀ : t.Nonempty
⊢ AEStronglyMeasurable f μ

Tactic:
obtain ⟨g, g_meas, gt, fg⟩ : ∃ g : α → β, Measurable g ∧ range g ⊆ t ∧ f =ᵐ[μ] g :=
      H.exists_ae_eq_range_subset ht h₀
    refine ⟨g, ?_, fg⟩
    exact stronglyMeasurable_iff_measurable_separable.2 ⟨g_meas, t_sep.mono gt⟩

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 : c ≤ ‖(hf.approx n) x‖
⊢ c / ‖(hf.approx n) x‖ ≤ 1

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

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

Goal state before:
pp: case pos
α : Type u_1
mα : MeasurableSpace α
μ : Measure α
s : Set α
f : α → ℝ≥0∞
hf : ∀ (a : α), f a ≤ 1
h'f : ∀ a ∈ sᶜ, f a = 0
x : α
hx : x ∈ s
⊢ f x ≤ s.indicator 1 x

Tactic:
simpa [hx] using hf x

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
⊢ ∃ n, ∀ (m_1 : ℕ), n ≤ m_1 → (fs m_1) x = (f_approx m_1) x

Tactic:
refine ⟨n, fun m hnm => ?_⟩

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)
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
Module: Mathlib.MeasureTheory.Integral.Lebesgue.Sub

Goal state before:
pp: case right
α : Type u_1
inst✝ : MeasurableSpace α
μ : Measure α
f : α → ℝ≥0∞
hf : ∫⁻ (a : α), f a ∂μ ≠ ∞
g : α → ℝ≥0∞
hmg : Measurable g
hgf : g ≤ f
hifg : ∫⁻ (a : α), f a ∂μ = ∫⁻ (a : α), g a ∂μ
s : Set α
hms : MeasurableSet s
⊢ ∫⁻ (x : α) in sᶜ, g x ∂μ ≠ ∞

Tactic:
rw [hifg] at hf

Goal state after:
case right
α : Type u_1
inst✝ : MeasurableSpace α
μ : Measure α
f g : α → ℝ≥0∞
hf : ∫⁻ (a : α), g a ∂μ ≠ ∞
hmg : Measurable g
hgf : g ≤ f
hifg : ∫⁻ (a : α), f a ∂μ = ∫⁻ (a : α), g a ∂μ
s : Set α
hms : MeasurableSet s
⊢ ∫⁻ (x : α) in sᶜ, g x ∂μ ≠ ∞
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 : AEMeasurable f μ
⊢ ∫⁻ (a : α), f a * r ∂μ = (∫⁻ (a : α), f a ∂μ) * r

Tactic:
simp_rw [mul_comm, lintegral_const_mul'' r hf]

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

Goal state before:
pp: case refine_2
α : Type u_1
m m0 : MeasurableSpace α
μ : Measure α
hm : m ≤ m0
f✝ : α → ℝ≥0∞
hf✝ : Measurable f✝
f g : α → ℝ≥0∞
a✝¹ : Disjoint (Function.support f) (Function.support g)
hf : Measurable f
a✝ : Measurable g
hf_prop : ∫⁻ (a : α), f a ∂μ.trim hm = ∫⁻ (a : α), f a ∂μ
hg_prop : ∫⁻ (a : α), g a ∂μ.trim hm = ∫⁻ (a : α), g a ∂μ
h_m : ∫⁻ (a : α), f a + g a ∂μ.trim hm = ∫⁻ (a : α), f a ∂μ + ∫⁻ (a : α), g a ∂μ.trim hm
h_m0 : ∫⁻ (a : α), f a + g a ∂μ = ∫⁻ (a : α), f a ∂μ + ∫⁻ (a : α), g a ∂μ
⊢ ∫⁻ (a : α), (f + g) a ∂μ.trim hm = ∫⁻ (a : α), (f + g) a ∂μ

Tactic:
hg_prop,

Goal state after:
case refine_2
α : Type u_1
m m0 : MeasurableSpace α
μ : Measure α
hm : m ≤ m0
f✝ : α → ℝ≥0∞
hf✝ : Measurable f✝
f g : α → ℝ≥0∞
a✝¹ : Disjoint (Function.support f) (Function.support g)
hf : Measurable f
a✝ : Measurable g
hf_prop : ∫⁻ (a : α), f a ∂μ.trim hm = ∫⁻ (a : α), f a ∂μ
hg_prop : ∫⁻ (a : α), g a ∂μ.trim hm = ∫⁻ (a : α), g a ∂μ
h_m : ∫⁻ (a : α), f a + g a ∂μ.trim hm = ∫⁻ (a : α), f a ∂μ + ∫⁻ (a : α), g a ∂μ
h_m0 : ∫⁻ (a : α), f a + g a ∂μ = ∫⁻ (a : α), f a ∂μ + ∫⁻ (a : α), g a ∂μ
⊢ ∫⁻ (a : α), (f + g) a ∂μ.trim hm = ∫⁻ (a : α), (f + g) a ∂μ
Module: Mathlib.MeasureTheory.Function.StronglyMeasurable.Basic

Goal state before:
pp: α : Type u_1
β : Type u_2
inst✝² : MeasurableSpace α
inst✝¹ : AddZeroClass β
inst✝ : TopologicalSpace β
P : (f : α → β) → StronglyMeasurable f → Prop
ind : ∀ (c : β) ⦃s : Set α⦄ (hs : MeasurableSet s), P (s.indicator fun x ↦ c) ⋯
add :
  ∀ ⦃f g : α → β⦄ (hf : StronglyMeasurable f) (hg : StronglyMeasurable g) (hfg : StronglyMeasurable (f + g)),
    Disjoint (support f) (support g) → P f hf → P g hg → P (f + g) hfg
lim :
  ∀ ⦃f : ℕ → α → β⦄ ⦃g : α → β⦄ (hf : ∀ (n : ℕ), StronglyMeasurable (f n)) (hg : StronglyMeasurable g),
    (∀ (n : ℕ), P (f n) ⋯) → (∀ (x : α), Tendsto (fun x_1 ↦ f x_1 x) atTop (𝓝 (g x))) → P g hg
f : α → β
hf : StronglyMeasurable f
⊢ P f hf

Tactic:
let s := hf.approx

Goal state after:
α : Type u_1
β : Type u_2
inst✝² : MeasurableSpace α
inst✝¹ : AddZeroClass β
inst✝ : TopologicalSpace β
P : (f : α → β) → StronglyMeasurable f → Prop
ind : ∀ (c : β) ⦃s : Set α⦄ (hs : MeasurableSet s), P (s.indicator fun x ↦ c) ⋯
add :
  ∀ ⦃f g : α → β⦄ (hf : StronglyMeasurable f) (hg : StronglyMeasurable g) (hfg : StronglyMeasurable (f + g)),
    Disjoint (support f) (support g) → P f hf → P g hg → P (f + g) hfg
lim :
  ∀ ⦃f : ℕ → α → β⦄ ⦃g : α → β⦄ (hf : ∀ (n : ℕ), StronglyMeasurable (f n)) (hg : StronglyMeasurable g),
    (∀ (n : ℕ), P (f n) ⋯) → (∀ (x : α), Tendsto (fun x_1 ↦ f x_1 x) atTop (𝓝 (g x))) → P g hg
f : α → β
hf : StronglyMeasurable f
s : ℕ → α →ₛ β := hf.approx
⊢ P f hf
Module: Mathlib.MeasureTheory.Function.StronglyMeasurable.Basic

Goal state before:
pp: α : Type u_1
β : Type u_2
inst✝² : MeasurableSpace α
inst✝¹ : Nonempty β
inst✝ : TopologicalSpace β
P : (f : α → β) → StronglyMeasurable f → Prop
const : ∀ (c : β), P (fun x ↦ c) ⋯
pcw :
  ∀ ⦃f g : α → β⦄ {s : Set α} (hf : StronglyMeasurable f) (hg : StronglyMeasurable g) (hs : MeasurableSet s),
    P f hf → P g hg → P (s.piecewise f g) ⋯
lim :
  ∀ ⦃f : ℕ → α → β⦄ ⦃g : α → β⦄ (hf : ∀ (n : ℕ), StronglyMeasurable (f n)) (hg : StronglyMeasurable g),
    (∀ (n : ℕ), P (f n) ⋯) → (∀ (x : α), Tendsto (fun x_1 ↦ f x_1 x) atTop (𝓝 (g x))) → P g hg
f : α → β
hf : StronglyMeasurable f
⊢ P f hf

Tactic:
let s := hf.approx

Goal state after:
α : Type u_1
β : Type u_2
inst✝² : MeasurableSpace α
inst✝¹ : Nonempty β
inst✝ : TopologicalSpace β
P : (f : α → β) → StronglyMeasurable f → Prop
const : ∀ (c : β), P (fun x ↦ c) ⋯
pcw :
  ∀ ⦃f g : α → β⦄ {s : Set α} (hf : StronglyMeasurable f) (hg : StronglyMeasurable g) (hs : MeasurableSet s),
    P f hf → P g hg → P (s.piecewise f g) ⋯
lim :
  ∀ ⦃f : ℕ → α → β⦄ ⦃g : α → β⦄ (hf : ∀ (n : ℕ), StronglyMeasurable (f n)) (hg : StronglyMeasurable g),
    (∀ (n : ℕ), P (f n) ⋯) → (∀ (x : α), Tendsto (fun x_1 ↦ f x_1 x) atTop (𝓝 (g x))) → P g hg
f : α → β
hf : StronglyMeasurable f
s : ℕ → α →ₛ β := hf.approx
⊢ P f hf
Module: Mathlib.Topology.Perfect

Goal state before:
pp: case left
α : Type u_1
inst✝¹ : TopologicalSpace α
C : Set α
inst✝ : SecondCountableTopology α
hclosed : IsClosed[inst✝¹] C
hunc : ¬C.Countable
V D : Set α
Vct : V.Countable
Dperf : Perfect D
VD : C = V
h : D = ∅
⊢ False

Tactic:
rw [VD] at hunc

Goal state after:
case left
α : Type u_1
inst✝¹ : TopologicalSpace α
C : Set α
inst✝ : SecondCountableTopology α
hclosed : IsClosed[inst✝¹] C
V : Set α
hunc : ¬V.Countable
D : Set α
Vct : V.Countable
Dperf : Perfect D
VD : C = V
h : D = ∅
⊢ False
Module: Mathlib.Analysis.Normed.Group.InfiniteSum

Goal state before:
pp: E : Type u_3
inst✝ : SeminormedAddCommGroup E
f : ℕ → E
g : ℕ → ℝ
hg✝ : CauchySeq fun n ↦ ∑ i ∈ range n, g i
hf : ∀ (i : ℕ), ‖f i‖ ≤ g i
ε : ℝ
hε : ε > 0
N n : ℕ
hg : ‖∑ k ∈ Ico N n, g k‖ < ε
hn : n ≥ N
⊢ ‖∑ k ∈ Ico N n, f k‖ < ε

Tactic:
calc
    ‖∑ k ∈ Ico N n, f k‖ ≤ ∑ k ∈ _, ‖f k‖ := norm_sum_le _ _
    _ ≤ ∑ k ∈ _, g k := sum_le_sum fun x _ => hf x
    _ ≤ ‖∑ k ∈ _, g k‖ := le_abs_self _
    _ < ε := hg

Goal state after:
Module: Mathlib.Topology.UnitInterval

Goal state before:
pp: α : Type u_1
inst✝² : AddCommGroup α
inst✝¹ : LinearOrder α
inst✝ : IsOrderedAddMonoid α
a b c✝ d✝ : α
h : a ≤ b
c d : α
hdc : d ≤ c
⊢ |↑(projIcc a b h c) - ↑(projIcc a b h d)| ≤ |c - d|

Tactic:
rw [abs_eq_self.2 (sub_nonneg.2 hdc),
    abs_eq_self.2 (sub_nonneg.2 <| mod_cast monotone_projIcc h hdc)]

Goal state after:
α : Type u_1
inst✝² : AddCommGroup α
inst✝¹ : LinearOrder α
inst✝ : IsOrderedAddMonoid α
a b c✝ d✝ : α
h : a ≤ b
c d : α
hdc : d ≤ c
⊢ ↑(projIcc a b h c) - ↑(projIcc a b h d) ≤ c - d
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
ε0 : 0 < ε
x : X
y : Y
h : glueDist Φ Ψ ε (Sum.inl x) (Sum.inr y) = 0
⊢ Sum.inl x = Sum.inr y

Tactic:
exfalso

Goal state after:
X : Type u
Y : Type v
Z : Type w
inst✝¹ : MetricSpace X
inst✝ : MetricSpace Y
Φ : Z → X
Ψ : Z → Y
ε : ℝ
ε0 : 0 < ε
x : X
y : Y
h : glueDist Φ Ψ ε (Sum.inl x) (Sum.inr y) = 0
⊢ False
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
ε0 : 0 < ε
x : Y
y : X
h : glueDist Φ Ψ ε (Sum.inr x) (Sum.inl y) = 0
⊢ Sum.inr x = Sum.inl y

Tactic:
exfalso

Goal state after:
X : Type u
Y : Type v
Z : Type w
inst✝¹ : MetricSpace X
inst✝ : MetricSpace Y
Φ : Z → X
Ψ : Z → Y
ε : ℝ
ε0 : 0 < ε
x : Y
y : X
h : glueDist Φ Ψ ε (Sum.inr x) (Sum.inl y) = 0
⊢ False
Module: Mathlib.Topology.MetricSpace.PiNat

Goal state before:
pp: case mpr
E : ℕ → Type u_1
x : (n : ℕ) → E n
n : ℕ
y : (n : ℕ) → E n
H : ∀ i < n, y i = x i
⊢ ∃ i, ∀ i_1 < n + 1, y i_1 = update x n i i_1

Tactic:
refine ⟨y n, fun i hi => ?_⟩

Goal state after:
case mpr
E : ℕ → Type u_1
x : (n : ℕ) → E n
n : ℕ
y : (n : ℕ) → E n
H : ∀ i < n, y i = x i
i : ℕ
hi : i < n + 1
⊢ y i = update x n (y n) i