mathlib-initiative/mathlib-tactics huggingface dataset:
Module: Mathlib.MeasureTheory.Constructions.BorelSpace.Real

Goal state before:
pp: case inl
⊢ Measurable fun x ↦ 0 * x

pp: case inr
c : EReal
hc : c ≠ 0
⊢ Measurable fun x ↦ c * x

Tactic:
· simp

Goal state after:
case inr
c : EReal
hc : c ≠ 0
⊢ Measurable fun x ↦ c * x
Module: Mathlib.MeasureTheory.Function.SimpleFunc

Goal state before:
pp: α : Type u_1
mα : MeasurableSpace α
motive : (α → ℝ≥0∞) → Prop
indicator : ∀ (c : ℝ≥0∞) ⦃s : Set α⦄, MeasurableSet s → motive (s.indicator fun x ↦ c)
add :
  ∀ ⦃f g : α → ℝ≥0∞⦄,
    Disjoint (support f) (support g) → Measurable f → Measurable g → motive f → motive g → motive (f + g)
iSup :
  ∀ ⦃f : ℕ → α → ℝ≥0∞⦄,
    (∀ (n : ℕ), Measurable (f n)) → Monotone f → (∀ (n : ℕ), motive (f n)) → motive fun x ↦ ⨆ n, f n x
f : α → ℝ≥0∞
hf : Measurable f
⊢ motive f

Tactic:
by
  convert! iSup (fun n => (eapprox f n).measurable) (monotone_eapprox f) _ using 2
  · rw [iSup_eapprox_apply hf]
  · exact fun n =>
      SimpleFunc.induction (fun c s hs => indicator c hs)
        (fun f g hfg hf hg => add hfg f.measurable g.measurable hf hg) (eapprox f n)

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

Goal state before:
pp: case hbc
α : Type u_1
β : Type u_5
f : α → β
inst✝¹ : NormedAddCommGroup β
inst✝ : NormedSpace ℝ β
m : MeasurableSpace α
hf : StronglyMeasurable f
c : ℝ
x : α
hfx : ‖f x‖ ≤ c
h_tendsto : Tendsto (fun n ↦ (hf.approx n) x) atTop (𝓝 0)
hfx0 : f x = 0
h_tendsto_norm : Tendsto (fun n ↦ ‖(hf.approx n) x‖) atTop (𝓝 0)
n : ℕ
⊢ ‖min 1 (c / ‖(hf.approx n) x‖)‖ ≤ ‖1‖

Tactic:
norm_one,

Goal state after:
case hbc
α : Type u_1
β : Type u_5
f : α → β
inst✝¹ : NormedAddCommGroup β
inst✝ : NormedSpace ℝ β
m : MeasurableSpace α
hf : StronglyMeasurable f
c : ℝ
x : α
hfx : ‖f x‖ ≤ c
h_tendsto : Tendsto (fun n ↦ (hf.approx n) x) atTop (𝓝 0)
hfx0 : f x = 0
h_tendsto_norm : Tendsto (fun n ↦ ‖(hf.approx n) x‖) atTop (𝓝 0)
n : ℕ
⊢ ‖min 1 (c / ‖(hf.approx n) x‖)‖ ≤ 1
Module: Mathlib.MeasureTheory.Function.StronglyMeasurable.Basic

Goal state before:
pp: α : Type u_1
β : Type u_5
f : α → β
inst✝¹ : NormedAddCommGroup β
inst✝ : NormedSpace ℝ β
m : MeasurableSpace α
hf : StronglyMeasurable f
c : ℝ
x : α
hfx : ‖f x‖ ≤ c
h_tendsto : Tendsto (fun n ↦ (hf.approx n) x) atTop (𝓝 0)
hfx0 : f x = 0
h_tendsto_norm : Tendsto (fun n ↦ ‖(hf.approx n) x‖) atTop (𝓝 0)
n : ℕ
⊢ ‖1‖ * ‖(hf.approx n) x‖ = ‖(hf.approx n) x‖

Tactic:
norm_one,

Goal state after:
α : Type u_1
β : Type u_5
f : α → β
inst✝¹ : NormedAddCommGroup β
inst✝ : NormedSpace ℝ β
m : MeasurableSpace α
hf : StronglyMeasurable f
c : ℝ
x : α
hfx : ‖f x‖ ≤ c
h_tendsto : Tendsto (fun n ↦ (hf.approx n) x) atTop (𝓝 0)
hfx0 : f x = 0
h_tendsto_norm : Tendsto (fun n ↦ ‖(hf.approx n) x‖) atTop (𝓝 0)
n : ℕ
⊢ 1 * ‖(hf.approx n) x‖ = ‖(hf.approx n) x‖
Module: Mathlib.MeasureTheory.Integral.Lebesgue.Basic

Goal state before:

Tactic:
(⨅ x ∈ s, f x) * μ s
  _ = ∫⁻ y in s, ⨅ x ∈ s, f x ∂μ := by simp
  _ ≤ ∫⁻ x in s, f x ∂μ := setLIntegral_mono' hs fun x hx ↦ iInf₂_le x hx

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

Goal state before:
pp: case mp
α : Type u_1
m : MeasurableSpace α
μ : Measure α
f : α → ℝ≥0∞
hf : AEMeasurable f μ
h : ∫⁻ (a : α), f a ∂μ = 0
meas_levels_0 : ∀ ε > 0, μ {x | ε ≤ f x} = 0
u : ℕ → ℝ≥0∞
bu : ∀ (n : ℕ), u n ∈ Ioo 0 1
tu : ∀ ε > 0, ∃ N, ∀ n ≥ N, u n ≤ ε
x : α
h' : 0 < f x
⊢ ∃ i, x ∈ {x | u i ≤ f x}

Tactic:
obtain ⟨n, hn⟩ := tu _ h'; use n, hn _ le_rfl

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

Goal state before:
pp: α : Type u_1
mα : MeasurableSpace α
μ : Measure α
s t : Set α
hs : MeasurableSet s
f : α → ℝ≥0∞
hf : ∀ a ∈ s, a ∈ t → f a ≤ 1
hf' : ∀ a ∈ s, a ∉ t → f a = 0
⊢ ∫⁻ (a : α) in s, f a ∂μ ≤ μ t

Tactic:
← lintegral_indicator hs

Goal state after:
α : Type u_1
mα : MeasurableSpace α
μ : Measure α
s t : Set α
hs : MeasurableSet s
f : α → ℝ≥0∞
hf : ∀ a ∈ s, a ∈ t → f a ≤ 1
hf' : ∀ a ∈ s, a ∉ t → f a = 0
⊢ ∫⁻ (a : α), s.indicator f a ∂μ ≤ μ t
Module: Mathlib.MeasureTheory.Integral.Lebesgue.Add

Goal state before:
pp: case intro.inl
α : Type u_1
β : Type u_2
m : MeasurableSpace α
μ : Measure α
inst✝ : Countable β
f : β → α → ℝ≥0∞
hf : ∀ (b : β), Measurable (f b)
h_directed : Directed (fun x1 x2 ↦ x1 ≤ x2) f
val✝ : Encodable β
h✝ : IsEmpty β
⊢ ∫⁻ (a : α), ⨆ b, f b a ∂μ = ⨆ b, ∫⁻ (a : α), f b a ∂μ

pp: case intro.inr
α : Type u_1
β : Type u_2
m : MeasurableSpace α
μ : Measure α
inst✝ : Countable β
f : β → α → ℝ≥0∞
hf : ∀ (b : β), Measurable (f b)
h_directed : Directed (fun x1 x2 ↦ x1 ≤ x2) f
val✝ : Encodable β
h✝ : Nonempty β
⊢ ∫⁻ (a : α), ⨆ b, f b a ∂μ = ⨆ b, ∫⁻ (a : α), f b a ∂μ

Tactic:
· simp

Goal state after:
case intro.inr
α : Type u_1
β : Type u_2
m : MeasurableSpace α
μ : Measure α
inst✝ : Countable β
f : β → α → ℝ≥0∞
hf : ∀ (b : β), Measurable (f b)
h_directed : Directed (fun x1 x2 ↦ x1 ≤ x2) f
val✝ : Encodable β
h✝ : Nonempty β
⊢ ∫⁻ (a : α), ⨆ b, f b a ∂μ = ⨆ b, ∫⁻ (a : α), f b a ∂μ
Module: Mathlib.MeasureTheory.Function.StronglyMeasurable.Basic

Goal state before:
pp: α : Type u_1
β : Type u_2
f g : α → β
mα : MeasurableSpace α
inst✝⁴ : TopologicalSpace β
inst✝³ : GroupWithZero β
inst✝² : ContinuousMul β
inst✝¹ : ContinuousInv₀ β
inst✝ : MetrizableSpace β
hf : StronglyMeasurable f
hg : StronglyMeasurable g
this✝¹ : MeasurableSpace β := borel β
this✝ : BorelSpace β
x : α
⊢ Tendsto (fun n ↦ ((fun n ↦ hf.approx n / (hg.approx n).restrict {x | g x ≠ 0}) n) x) atTop (𝓝 ((f / g) x))

Tactic:
have : MeasurableSet {x | g x ≠ 0} := ((MeasurableSet.singleton 0).preimage hg.measurable).compl

Goal state after:
α : Type u_1
β : Type u_2
f g : α → β
mα : MeasurableSpace α
inst✝⁴ : TopologicalSpace β
inst✝³ : GroupWithZero β
inst✝² : ContinuousMul β
inst✝¹ : ContinuousInv₀ β
inst✝ : MetrizableSpace β
hf : StronglyMeasurable f
hg : StronglyMeasurable g
this✝¹ : MeasurableSpace β := borel β
this✝ : BorelSpace β
x : α
this : MeasurableSet {x | g x ≠ 0}
⊢ Tendsto (fun n ↦ ((fun n ↦ hf.approx n / (hg.approx n).restrict {x | g x ≠ 0}) n) x) atTop (𝓝 ((f / g) x))
Module: Mathlib.MeasureTheory.Function.StronglyMeasurable.Basic

Goal state before:
pp: α : Type u_5
E : Type u_6
x✝ : MeasurableSpace α
inst✝⁵ : AddCancelMonoid E
inst✝⁴ : TopologicalSpace E
inst✝³ : MeasurableSpace E
inst✝² : BorelSpace E
inst✝¹ : ContinuousAdd E
inst✝ : PseudoMetrizableSpace E
g f : α → E
hg : Measurable g
hf : StronglyMeasurable f
⊢ Measurable (g + f)

Tactic:
rcases hf with ⟨φ, hφ⟩

Goal state after:
α : Type u_5
E : Type u_6
x✝ : MeasurableSpace α
inst✝⁵ : AddCancelMonoid E
inst✝⁴ : TopologicalSpace E
inst✝³ : MeasurableSpace E
inst✝² : BorelSpace E
inst✝¹ : ContinuousAdd E
inst✝ : PseudoMetrizableSpace E
g f : α → E
hg : Measurable g
φ : ℕ → α →ₛ E
hφ : ∀ (x : α), Tendsto (fun n ↦ (φ n) x) atTop (𝓝 (f x))
⊢ Measurable (g + f)
Module: Mathlib.MeasureTheory.Function.StronglyMeasurable.Basic

Goal state before:
pp: α : Type u_5
E : Type u_6
x✝ : MeasurableSpace α
inst✝⁵ : AddCancelMonoid E
inst✝⁴ : TopologicalSpace E
inst✝³ : MeasurableSpace E
inst✝² : BorelSpace E
inst✝¹ : ContinuousAdd E
inst✝ : PseudoMetrizableSpace E
g f : α → E
hg : Measurable g
hf : StronglyMeasurable f
⊢ Measurable (f + g)

Tactic:
rcases hf with ⟨φ, hφ⟩

Goal state after:
α : Type u_5
E : Type u_6
x✝ : MeasurableSpace α
inst✝⁵ : AddCancelMonoid E
inst✝⁴ : TopologicalSpace E
inst✝³ : MeasurableSpace E
inst✝² : BorelSpace E
inst✝¹ : ContinuousAdd E
inst✝ : PseudoMetrizableSpace E
g f : α → E
hg : Measurable g
φ : ℕ → α →ₛ E
hφ : ∀ (x : α), Tendsto (fun n ↦ (φ n) x) atTop (𝓝 (f x))
⊢ Measurable (f + g)
Module: Mathlib.MeasureTheory.Function.StronglyMeasurable.Basic

Goal state before:
pp: α : Type u_1
β : Type u_2
inst✝⁵ : MeasurableSpace α
inst✝⁴ : TopologicalSpace α
inst✝³ : OpensMeasurableSpace α
inst✝² : MeasurableSingletonClass α
inst✝¹ : TopologicalSpace β
inst✝ : PseudoMetrizableSpace β
h : SecondCountableTopologyEither α β
f : α → β
s : Set α
hf : ContinuousOn f s
hs : sᶜ.Countable
h's : MeasurableSet s
this✝ : f = fun x ↦ if hx : x ∈ s then f ↑⟨x, hx⟩ else f ↑⟨x, hx⟩
this : Countable ↑sᶜ
⊢ StronglyMeasurable fun x ↦ f ↑x

Tactic:
exact MeasureTheory.StronglyMeasurable.of_discrete

Goal state after:
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
⊢ MeasurableSet s

Tactic:
have : MeasurableSet (s ∩ univ) := hs univ (by simpa)

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
this : MeasurableSet (s ∩ univ)
⊢ MeasurableSet s
Module: Mathlib.Topology.Perfect

Goal state before:
pp: 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}

pp: 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})

Tactic:
· simp

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
⊢ {x} ∪ U \ {x} ⊆ {x} ∪ closure[inst✝¹] (U \ {x})
Module: Mathlib.Analysis.Normed.Group.InfiniteSum

Goal state before:
pp: ι : Type u_1
E : Type u_3
inst✝¹ : SeminormedAddCommGroup E
inst✝ : CompleteSpace E
f : ι → E
⊢ Summable f ↔ ∀ ε > 0, ∃ s, ∀ (t : Finset ι), Disjoint t s → ‖∑ i ∈ t, f i‖ < ε

Tactic:
rw [summable_iff_cauchySeq_finset, cauchySeq_finset_iff_vanishing_norm]

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

Goal state before:
pp: case refine_1
α : Type u_5
β : Type u_6
ι : Type u_7
inst✝⁷ : TopologicalSpace ι
inst✝⁶ : MetrizableSpace ι
inst✝⁵ : MeasurableSpace ι
inst✝⁴ : SecondCountableTopology ι
inst✝³ : OpensMeasurableSpace ι
inst✝² : TopologicalSpace β
inst✝¹ : PseudoMetrizableSpace β
inst✝ : MeasurableSpace α
u : ι → α → β
hu_cont : ∀ (x : α), Continuous[inst✝⁷, inst✝²] fun i ↦ u i x
h : ∀ (i : ι), StronglyMeasurable (u i)
this✝¹ : MeasurableSpace β := borel β
this✝ : BorelSpace β
t_sf : ℕ → ι →ₛ ι
ht_sf : ∀ (j : ι) (x : α), Tendsto (fun n ↦ u ((t_sf n) j) x) atTop (𝓝 (u j x))
U : ℕ → ι × α → β := fun n p ↦ u ((t_sf n) p.1) p.2
h_tendsto : Tendsto U atTop (𝓝 fun p ↦ u p.1 p.2)
n : ℕ
this : (fun p ↦ u (↑p.1) p.2) = (fun p ↦ u (↑p.2) p.1) ∘ Prod.swap
⊢ Measurable fun p ↦ u (↑p.1) p.2

Tactic:
rw [this, measurable_swap_iff]

Goal state after:
case refine_1
α : Type u_5
β : Type u_6
ι : Type u_7
inst✝⁷ : TopologicalSpace ι
inst✝⁶ : MetrizableSpace ι
inst✝⁵ : MeasurableSpace ι
inst✝⁴ : SecondCountableTopology ι
inst✝³ : OpensMeasurableSpace ι
inst✝² : TopologicalSpace β
inst✝¹ : PseudoMetrizableSpace β
inst✝ : MeasurableSpace α
u : ι → α → β
hu_cont : ∀ (x : α), Continuous[inst✝⁷, inst✝²] fun i ↦ u i x
h : ∀ (i : ι), StronglyMeasurable (u i)
this✝¹ : MeasurableSpace β := borel β
this✝ : BorelSpace β
t_sf : ℕ → ι →ₛ ι
ht_sf : ∀ (j : ι) (x : α), Tendsto (fun n ↦ u ((t_sf n) j) x) atTop (𝓝 (u j x))
U : ℕ → ι × α → β := fun n p ↦ u ((t_sf n) p.1) p.2
h_tendsto : Tendsto U atTop (𝓝 fun p ↦ u p.1 p.2)
n : ℕ
this : (fun p ↦ u (↑p.1) p.2) = (fun p ↦ u (↑p.2) p.1) ∘ Prod.swap
⊢ Measurable fun p ↦ u (↑p.2) p.1
Module: Mathlib.Topology.Metrizable.CompletelyMetrizable

Goal state before:
pp: X : Type u_3
ht : TopologicalSpace X
h : IsCompletelyMetrizableSpace X
⊢ CompleteSpace X

Tactic:
by
  convert! h.complete.choose_spec.2
  exact MetricSpace.replaceTopology_eq _ _

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

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

Tactic:
· simp

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

Goal state before:
pp: case inr.inl
E : ℕ → Type u_1
x z : (n : ℕ) → E n
hxz : x ≠ z
⊢ dist x z ≤ max (dist x x) (dist x z)

pp: case inr.inr
E : ℕ → Type u_1
x y z : (n : ℕ) → E n
hxz : x ≠ z
hxy : x ≠ y
⊢ dist x z ≤ max (dist x y) (dist y z)

Tactic:
· simp

Goal state after:
case inr.inr
E : ℕ → Type u_1
x y z : (n : ℕ) → E n
hxz : x ≠ z
hxy : x ≠ y
⊢ dist x z ≤ max (dist x y) (dist y z)
Module: Mathlib.Topology.MetricSpace.PiNat

Goal state before:
pp: case inr.inr.inl
E : ℕ → Type u_1
x y : (n : ℕ) → E n
hxy hxz : x ≠ y
⊢ dist x y ≤ max (dist x y) (dist y y)

pp: case inr.inr.inr
E : ℕ → Type u_1
x y z : (n : ℕ) → E n
hxz : x ≠ z
hxy : x ≠ y
hyz : y ≠ z
⊢ dist x z ≤ max (dist x y) (dist y z)

Tactic:
· simp

Goal state after:
case inr.inr.inr
E : ℕ → Type u_1
x y z : (n : ℕ) → E n
hxz : x ≠ z
hxy : x ≠ y
hyz : y ≠ z
⊢ dist x z ≤ max (dist x y) (dist y z)
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)
y : (n : ℕ) × X n
hy : y.fst ≤ 0
i : ℕ
x : X i
hx : ⟨i, x⟩.fst ≤ 0
⊢ inductiveLimitDist f ⟨i, x⟩ y = dist (leRecOn hx (fun {k} ↦ f k) ⟨i, x⟩.snd) (leRecOn hy (fun {k} ↦ f k) y.snd)

Tactic:
obtain ⟨j, y⟩ := y

Goal state after:
X : ℕ → Type u
inst✝ : (n : ℕ) → MetricSpace (X n)
f : (n : ℕ) → X n → X (n + 1)
I : ∀ (n : ℕ), Isometry (f n)
i : ℕ
x : X i
hx : ⟨i, x⟩.fst ≤ 0
j : ℕ
y : X j
hy : ⟨j, y⟩.fst ≤ 0
⊢ inductiveLimitDist f ⟨i, x⟩ ⟨j, y⟩ =
    dist (leRecOn hx (fun {k} ↦ f k) ⟨i, x⟩.snd) (leRecOn hy (fun {k} ↦ f k) ⟨j, y⟩.snd)
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)
x y : (n : ℕ) × X n
m : ℕ := max x.fst y.fst
hx : x.fst ≤ m
hy : y.fst ≤ m
⊢ inductiveLimitDist f x y = inductiveLimitDist f y x

Tactic:
rw [inductiveLimitDist_eq_dist I x y m hx hy, inductiveLimitDist_eq_dist I y x m hy hx,
      dist_comm]

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

Goal state before:
pp: case refine_2.inl
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 : (n : ℕ) → E n
⊢ dist (f x) (f x) ≤ dist x x

pp: case refine_2.inr
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
⊢ dist (f x) (f y) ≤ dist x y

Tactic:
· simp

Goal state after:
case refine_2.inr
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
⊢ dist (f x) (f y) ≤ dist x y
Module: Mathlib.MeasureTheory.Measure.MutuallySingular

Goal state before:
pp: α : Type u_1
m0 : MeasurableSpace α
μ : Measure α
s : Set α
hs : MeasurableSet s
hμs : μ s = 0
hμs_compl : μ sᶜ = 0
⊢ μ = 0

Tactic:
suffices μ Set.univ = 0 by rwa [measure_univ_eq_zero] at this

Goal state after:
α : Type u_1
m0 : MeasurableSpace α
μ : Measure α
s : Set α
hs : MeasurableSet s
hμs : μ s = 0
hμs_compl : μ sᶜ = 0
⊢ μ univ = 0
Module: Mathlib.MeasureTheory.Measure.Typeclasses.Probability

Goal state before:
pp: case inl
α : Type u_1
m0 : MeasurableSpace α
s : Set α
p : ℝ≥0∞
s_mble : MeasurableSet s
inst✝ : IsZeroOrProbabilityMeasure 0
hμs : p ≤ 0 s
⊢ 0 sᶜ ≤ 1 - p

pp: case inr
α : Type u_1
m0 : MeasurableSpace α
μ : Measure α
s : Set α
inst✝ : IsZeroOrProbabilityMeasure μ
p : ℝ≥0∞
hμs : p ≤ μ s
s_mble : MeasurableSet s
h : IsProbabilityMeasure μ
⊢ μ sᶜ ≤ 1 - p

Tactic:
· simp

Goal state after:
case inr
α : Type u_1
m0 : MeasurableSpace α
μ : Measure α
s : Set α
inst✝ : IsZeroOrProbabilityMeasure μ
p : ℝ≥0∞
hμs : p ≤ μ s
s_mble : MeasurableSet s
h : IsProbabilityMeasure μ
⊢ μ sᶜ ≤ 1 - p
Module: Mathlib.MeasureTheory.Measure.Dirac

Goal state before:
pp: case pos
α : Type u_1
inst✝¹ : MeasurableSpace α
inst✝ : MeasurableSingletonClass α
a : α
s : Set α
h : a ∈ s
⊢ (dirac a) s = s.indicator 1 a

pp: case neg
α : Type u_1
inst✝¹ : MeasurableSpace α
inst✝ : MeasurableSingletonClass α
a : α
s : Set α
h : a ∉ s
⊢ (dirac a) s = s.indicator 1 a

Tactic:
· rw [dirac_apply_of_mem h, indicator_of_mem h, Pi.one_apply]

Goal state after:
case neg
α : Type u_1
inst✝¹ : MeasurableSpace α
inst✝ : MeasurableSingletonClass α
a : α
s : Set α
h : a ∉ s
⊢ (dirac a) s = s.indicator 1 a
Module: Mathlib.MeasureTheory.Measure.MutuallySingular

Goal state before:
pp: α : Type u_1
m0 : MeasurableSpace α
μ ν : Measure α
h : Disjoint μ ν
s : ℕ → Set α
hs₂ : ∀ (n : ℕ), μ (s n) = 0
hs₃ : ∀ (n : ℕ), ν (s n)ᶜ ≤ (1 / 2) ^ n
⊢ μ ⟂ₘ ν

Tactic:
refine Measure.MutuallySingular.mk (t := (⋃ n, s n)ᶜ) (measure_iUnion_null hs₂) ?_ ?_

Goal state after:
case refine_1
α : Type u_1
m0 : MeasurableSpace α
μ ν : Measure α
h : Disjoint μ ν
s : ℕ → Set α
hs₂ : ∀ (n : ℕ), μ (s n) = 0
hs₃ : ∀ (n : ℕ), ν (s n)ᶜ ≤ (1 / 2) ^ n
⊢ ν (⋃ n, s n)ᶜ = 0

case refine_2
α : Type u_1
m0 : MeasurableSpace α
μ ν : Measure α
h : Disjoint μ ν
s : ℕ → Set α
hs₂ : ∀ (n : ℕ), μ (s n) = 0
hs₃ : ∀ (n : ℕ), ν (s n)ᶜ ≤ (1 / 2) ^ n
⊢ univ ⊆ (⋃ i, s i) ∪ (⋃ n, s n)ᶜ
Module: Mathlib.MeasureTheory.Constructions.Polish.Basic

Goal state before:
pp: case h₂
α : Type u_1
ι : Type u_2
inst✝² : TopologicalSpace α
inst✝¹ : Countable ι
inst✝ : T2Space α
s : ι → Set α
hs : ∀ (n : ι), AnalyticSet (s n)
i₀ : ι
β : ι → Type
hβ : (n : ι) → TopologicalSpace (β n)
h'β : ∀ (n : ι), PolishSpace (β n)
f : (n : ι) → β n → α
f_cont : ∀ (n : ι), Continuous[hβ n, inst✝²] (f n)
f_range : ∀ (n : ι), range (f n) = s n
γ : Type u_2 := (n : ι) → β n
t : Set γ := ⋂ n, {x | f n (x n) = f i₀ (x i₀)}
t_closed : IsClosed[Pi.topologicalSpace] t
this : PolishSpace ↑t
F : ↑t → α := fun x ↦ f i₀ (↑x i₀)
F_cont : Continuous[instTopologicalSpaceSubtype, inst✝²] F
y : α
hy : y ∈ ⋂ n, s n
x : (n : ι) → β n
hx : ∀ (n : ι), f n (x n) = y
xt : x ∈ t
⊢ F ⟨x, xt⟩ = y

Tactic:
exact hx i₀

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

Goal state before:
pp: α : Type u_1
m0 : MeasurableSpace α
μ ν : Measure α
h : μ ⟂ₘ ν
h_bot_iff : ∀ (ξ : Measure α), ξ ≤ ⊥ ↔ ξ = 0
ξ : Measure α
⊢ ξ ≤ μ → ξ ≤ ν → ξ ≤ ⊥

Tactic:
hξμ

Goal state after:
α : Type u_1
m0 : MeasurableSpace α
μ ν : Measure α
h : μ ⟂ₘ ν
h_bot_iff : ∀ (ξ : Measure α), ξ ≤ ⊥ ↔ ξ = 0
ξ : Measure α
hξμ : ξ ≤ μ
⊢ ξ ≤ ν → ξ ≤ ⊥
Module: Mathlib.MeasureTheory.Measure.Count

Goal state before:
pp: α : Type u_1
β : Type u_2
inst✝¹ : MeasurableSpace α
inst✝ : MeasurableSpace β
f : α → β
hf : Function.Injective f
h2f : Measurable f
s : Set β
hs : MeasurableSet s
x✝ : s.Nonempty
⊢ ↑(f ⁻¹' s).encard ≤ ↑s.encard

Tactic:
← hf.encard_image

Goal state after:
α : Type u_1
β : Type u_2
inst✝¹ : MeasurableSpace α
inst✝ : MeasurableSpace β
f : α → β
hf : Function.Injective f
h2f : Measurable f
s : Set β
hs : MeasurableSet s
x✝ : s.Nonempty
⊢ ↑(f '' f ⁻¹' s).encard ≤ ↑s.encard
Module: Mathlib.MeasureTheory.Measure.Dirac

Goal state before:
pp: case neg
α : Type u_1
inst✝ : MeasurableSpace α
x y : α
h : ∀ (x_1 : Set α), MeasurableSet x_1 → x ∈ x_1 → y ∈ x_1
A : Set α
A_mble : MeasurableSet A
x_in_A : x ∉ A
⊢ x ∈ A ↔ y ∈ A

Tactic:
· simpa only [x_in_A, false_iff] using! h Aᶜ (MeasurableSet.compl_iff.mpr A_mble) x_in_A

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

Goal state before:
pp: α : Type u_1
inst✝ : MeasurableSpace α
x y : α
⊢ dirac x ≠ dirac y ↔ ∃ A, MeasurableSet A ∧ x ∈ A ∧ y ∉ A

Tactic:
apply not_iff_not.mp
  simp only [ne_eq, not_not, not_exists, not_and, dirac_eq_dirac_iff_forall_mem_iff_mem]
  refine ⟨fun h A A_mble ↦ by simp only [h A A_mble, imp_self], fun h A A_mble ↦ ?_⟩
  by_cases x_in_A : x ∈ A
  · simp only [x_in_A, h A A_mble x_in_A]
  · simpa only [x_in_A, false_iff] using! h Aᶜ (MeasurableSet.compl_iff.mpr A_mble) x_in_A

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

Goal state before:
pp: case inl
α : Type u_2
inst✝³ : MetricSpace α
inst✝² : CompleteSpace α
inst✝¹ : SecondCountableTopology α
inst✝ : Nonempty α
this : MetricSpace (ℕ → ℕ) := metricSpaceNatNat
I0 : 0 < 1 / 2
I1 : 1 / 2 < 1
u : ℕ → α
hu : DenseRange u
s : Set (ℕ → ℕ) := {x | (⋂ n, closedBall (u (x n)) ((1 / 2) ^ n)).Nonempty}
g : ↑s → α := fun x ↦ Set.Nonempty.some ⋯
A : ∀ (x : ↑s) (n : ℕ), dist (g x) (u (↑x n)) ≤ (1 / 2) ^ n
x : ↑s
hxy : dist x x < 1
⊢ dist (g x) (g x) ≤ 4 * dist x x

pp: case inr
α : Type u_2
inst✝³ : MetricSpace α
inst✝² : CompleteSpace α
inst✝¹ : SecondCountableTopology α
inst✝ : Nonempty α
this : MetricSpace (ℕ → ℕ) := metricSpaceNatNat
I0 : 0 < 1 / 2
I1 : 1 / 2 < 1
u : ℕ → α
hu : DenseRange u
s : Set (ℕ → ℕ) := {x | (⋂ n, closedBall (u (x n)) ((1 / 2) ^ n)).Nonempty}
g : ↑s → α := fun x ↦ Set.Nonempty.some ⋯
A : ∀ (x : ↑s) (n : ℕ), dist (g x) (u (↑x n)) ≤ (1 / 2) ^ n
y x : ↑s
hxy : dist x y < 1
hne : x ≠ y
⊢ dist (g x) (g y) ≤ 4 * dist x y

Tactic:
· simp

Goal state after:
case inr
α : Type u_2
inst✝³ : MetricSpace α
inst✝² : CompleteSpace α
inst✝¹ : SecondCountableTopology α
inst✝ : Nonempty α
this : MetricSpace (ℕ → ℕ) := metricSpaceNatNat
I0 : 0 < 1 / 2
I1 : 1 / 2 < 1
u : ℕ → α
hu : DenseRange u
s : Set (ℕ → ℕ) := {x | (⋂ n, closedBall (u (x n)) ((1 / 2) ^ n)).Nonempty}
g : ↑s → α := fun x ↦ Set.Nonempty.some ⋯
A : ∀ (x : ↑s) (n : ℕ), dist (g x) (u (↑x n)) ≤ (1 / 2) ^ n
y x : ↑s
hxy : dist x y < 1
hne : x ≠ y
⊢ dist (g x) (g y) ≤ 4 * dist x y
Module: Mathlib.MeasureTheory.Measure.GiryMonad

Goal state before:
pp: α : Type u_1
mα : MeasurableSpace α
⊢ Measurable dirac

Tactic:
refine measurable_of_measurable_coe _ fun s hs => ?_
  simp_rw [dirac_apply' _ hs]
  exact measurable_one.indicator hs

Goal state after: