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

Goal state before:
pp: case refine_1.mpr
α : Type u_3
β : Type u_4
g : β → Set (Set α)
s : Set β
h_pi : ∀ b ∈ s, IsPiSystem (g b)
T : Finset ↑s
f : ↑s → Set α
h_t' : ∀ b ∈ T, f b ∈ (g ∘ Subtype.val) b
h_t : ⋂ b ∈ T, f b ∈ generatePiSystem (⋃ b ∈ s, g b)
this : ⋂ b ∈ T, f b ∈ generatePiSystem (⋃ b, (g ∘ Subtype.val) b)
a : α
⊢ (∀ (a_1 : β) (b : a_1 ∈ s), ⟨a_1, b⟩ ∈ T → a ∈ Function.extend (fun x ↦ ↑x) f (fun x ↦ ∅) ↑⟨a_1, b⟩) →
    ∀ (a_2 : β) (b : a_2 ∈ s), ⟨a_2, b⟩ ∈ T → a ∈ f ⟨a_2, b⟩

Tactic:
intro h1

Goal state after:
case refine_1.mpr
α : Type u_3
β : Type u_4
g : β → Set (Set α)
s : Set β
h_pi : ∀ b ∈ s, IsPiSystem (g b)
T : Finset ↑s
f : ↑s → Set α
h_t' : ∀ b ∈ T, f b ∈ (g ∘ Subtype.val) b
h_t : ⋂ b ∈ T, f b ∈ generatePiSystem (⋃ b ∈ s, g b)
this : ⋂ b ∈ T, f b ∈ generatePiSystem (⋃ b, (g ∘ Subtype.val) b)
a : α
h1 : ∀ (a_1 : β) (b : a_1 ∈ s), ⟨a_1, b⟩ ∈ T → a ∈ Function.extend (fun x ↦ ↑x) f (fun x ↦ ∅) ↑⟨a_1, b⟩
⊢ ∀ (a_1 : β) (b : a_1 ∈ s), ⟨a_1, b⟩ ∈ T → a ∈ f ⟨a_1, b⟩
Module: Mathlib.MeasureTheory.OuterMeasure.Induced

Goal state before:
pp: α : Type u_2
m : OuterMeasure α
m0 m1 : MeasurableSpace α
h : m0 ≤ m1
s : Set α
hs : MeasurableSet s
⊢ m.trim s ≤ m s

Tactic:
rw [trim_eq _ (h s hs)]

Goal state after:
Module: Mathlib.Order.Interval.Set.Monotone

Goal state before:
pp: α : Type u_1
inst✝³ : LinearOrder α
inst✝² : SuccOrder α
inst✝¹ : IsSuccArchimedean α
inst✝ : OrderBot α
n : α
φ : α → α
hφ : StrictMonoOn φ (Iic n)
⊢ ∀ m ≤ n, m ≤ φ m

Tactic:
revert hφ

Goal state after:
α : Type u_1
inst✝³ : LinearOrder α
inst✝² : SuccOrder α
inst✝¹ : IsSuccArchimedean α
inst✝ : OrderBot α
n : α
φ : α → α
⊢ StrictMonoOn φ (Iic n) → ∀ m ≤ n, m ≤ φ m
Module: Mathlib.MeasureTheory.Measure.Comap

Goal state before:
pp: case pos
α : Type u_1
β : Type u_2
s : Set α
mα : MeasurableSpace α
mβ : MeasurableSpace β
f : α → β
μ : Measure β
hs : NullMeasurableSet s (comap f μ)
hf : Injective f ∧ ∀ (t : Set α), MeasurableSet t → NullMeasurableSet (f '' t) μ
⊢ (comap f μ) s ≤ μ (f '' s)

Tactic:
rw [comap_apply₀ _ _ hf.1 hf.2 hs]

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

Goal state before:
pp: case refine_2
α : Type u_1
β : Type u_2
s : Set α
mα : MeasurableSpace α
mβ : MeasurableSpace β
f : α → β
μ : Measure β
hfi : Injective f
hf : ∀ (s : Set α), MeasurableSet s → NullMeasurableSet (f '' s) μ
hs : NullMeasurableSet s (comap f μ)
⊢ NullMeasurableSet (f '' toMeasurable (comap f μ) s) μ

pp: case refine_1
α : Type u_1
β : Type u_2
s : Set α
mα : MeasurableSpace α
mβ : MeasurableSpace β
f : α → β
μ : Measure β
hfi : Injective f
hf : ∀ (s : Set α), MeasurableSet s → NullMeasurableSet (f '' s) μ
hs : NullMeasurableSet s (comap f μ)
⊢ f '' s =ᵐ[μ] f '' toMeasurable (comap f μ) s

Tactic:
· exact hf _ (measurableSet_toMeasurable _ _)

Goal state after:
case refine_1
α : Type u_1
β : Type u_2
s : Set α
mα : MeasurableSpace α
mβ : MeasurableSpace β
f : α → β
μ : Measure β
hfi : Injective f
hf : ∀ (s : Set α), MeasurableSet s → NullMeasurableSet (f '' s) μ
hs : NullMeasurableSet s (comap f μ)
⊢ f '' s =ᵐ[μ] f '' toMeasurable (comap f μ) s
Module: Mathlib.MeasureTheory.Measure.Comap

Goal state before:
pp: α : Type u_1
β : Type u_2
mα : MeasurableSpace α
mβ : MeasurableSpace β
f : α → β
μ : Measure β
c : ℝ≥0∞
⊢ comap f (c • μ) = c • comap f μ

Tactic:
obtain rfl | hc := eq_or_ne c 0

Goal state after:
case inl
α : Type u_1
β : Type u_2
mα : MeasurableSpace α
mβ : MeasurableSpace β
f : α → β
μ : Measure β
⊢ comap f (0 • μ) = 0 • comap f μ

case inr
α : Type u_1
β : Type u_2
mα : MeasurableSpace α
mβ : MeasurableSpace β
f : α → β
μ : Measure β
c : ℝ≥0∞
hc : c ≠ 0
⊢ comap f (c • μ) = c • comap f μ
Module: Mathlib.MeasureTheory.Measure.Typeclasses.Finite

Goal state before:
pp: α : Type u_1
m0 : MeasurableSpace α
μ : Measure α
hμ : IsFiniteMeasure μ
f : ℕ → Set α
hf₁ : ∀ (i : ℕ), MeasurableSet (f i)
hf₂ : Pairwise (Disjoint on f)
⊢ Summable fun x ↦ μ.real (f x)

Tactic:
apply ENNReal.summable_toReal
  rw [← MeasureTheory.measure_iUnion hf₂ hf₁]
  exact ne_of_lt (measure_lt_top _ _)

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

Goal state before:
pp: 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)
n : ℕ
⊢ μ (w n) < ∞

Tactic:
w,

Goal state after:
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)
n : ℕ
⊢ μ (toMeasurable μ (t ∩ v n)) < ∞
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
inst✝² : TopologicalSpace α
inst✝¹ : SecondCountableTopology α
m : MeasurableSpace α
μ : Measure α
inst✝ : IsLocallyFiniteMeasure μ
h✝ : Nonempty α
inhabited_h : Inhabited α
S : Set (Set α) := {s | IsOpen[inst✝²] s ∧ μ s < ∞}
T : Set (Set α)
T_count : T.Countable
TS : T ⊆ S
hT : ⋃₀ T = univ
T_ne : T.Nonempty
f : ℕ → Set α
hf : T = range f
fS : ∀ (n : ℕ), f n ∈ S
x : α
⊢ x ∈ ⋃₀ T

Tactic:
simp only [hT, mem_univ]

Goal state after:
Module: Mathlib.Data.Set.MemPartition

Goal state before:
pp: case succ
α : Type u_1
f : ℕ → Set α
n : ℕ
ih : ∀ {u v : Set α}, u ∈ memPartition f n → v ∈ memPartition f n → u ≠ v → Disjoint u v
u v : Set α
hu : u ∈ memPartition f (n + 1)
hv : v ∈ memPartition f (n + 1)
huv : u ≠ v
⊢ Disjoint u v

Tactic:
rw [memPartition_succ] at hu hv

Goal state after:
case succ
α : Type u_1
f : ℕ → Set α
n : ℕ
ih : ∀ {u v : Set α}, u ∈ memPartition f n → v ∈ memPartition f n → u ≠ v → Disjoint u v
u v : Set α
hu : u ∈ {s | ∃ u ∈ memPartition f n, s = u ∩ f n ∨ s = u \ f n}
hv : v ∈ {s | ∃ u ∈ memPartition f n, s = u ∩ f n ∨ s = u \ f n}
huv : u ≠ v
⊢ Disjoint u v
Module: Mathlib.MeasureTheory.Measure.MeasureSpace

Goal state before:
pp: α : Type u_1
m0 : MeasurableSpace α
μ ν : Measure α
s t : Set α
h : (μ + ν) t ≠ ∞
h' : s ⊆ t
h'' : (μ + ν) s = (μ + ν) t
this : μ t + ν t ≤ μ s + ν t
⊢ ν t ≠ ∞

Tactic:
exact ne_top_of_le_ne_top h (le_add_left le_rfl)

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

Goal state before:
pp: α : Type u_2
ι : Type u_6
m0 : MeasurableSpace α
p : α → Prop
s : Finset ι
μ : ι → Measure α
⊢ (∀ᵐ (x : α) ∂∑ i ∈ s, μ i, p x) ↔ ∀ i ∈ s, ∀ᵐ (x : α) ∂μ i, p x

Tactic:
induction s using Finset.cons_induction

Goal state after:
case empty
α : Type u_2
ι : Type u_6
m0 : MeasurableSpace α
p : α → Prop
μ : ι → Measure α
⊢ (∀ᵐ (x : α) ∂∑ i ∈ ∅, μ i, p x) ↔ ∀ i ∈ ∅, ∀ᵐ (x : α) ∂μ i, p x

case cons
α : Type u_2
ι : Type u_6
m0 : MeasurableSpace α
p : α → Prop
μ : ι → Measure α
a✝¹ : ι
s✝ : Finset ι
h✝ : a✝¹ ∉ s✝
a✝ : (∀ᵐ (x : α) ∂∑ i ∈ s✝, μ i, p x) ↔ ∀ i ∈ s✝, ∀ᵐ (x : α) ∂μ i, p x
⊢ (∀ᵐ (x : α) ∂∑ i ∈ Finset.cons a✝¹ s✝ h✝, μ i, p x) ↔ ∀ i ∈ Finset.cons a✝¹ s✝ h✝, ∀ᵐ (x : α) ∂μ i, p x
Module: Mathlib.Order.Filter.CountableSeparatingOn

Goal state before:
pp: α : Type u_1
β : Type u_2
l : Filter α
inst✝ : CountableInterFilter l
f g : α → β
p : Set β → Prop
s : Set β
h' : HasCountableSeparatingOn β p s
hf : ∀ᶠ (x : α) in l, f x ∈ s
hg : ∀ᶠ (x : α) in l, g x ∈ s
h : ∀ (U : Set β), p U → ∀ᶠ (x : α) in l, f x ∈ U ↔ g x ∈ U
⊢ f =ᶠ[l] g

Tactic:
by
  rcases h'.1 with ⟨S, hSc, hSp, hS⟩
  have H : ∀ᶠ x in l, ∀ s ∈ S, f x ∈ s ↔ g x ∈ s :=
    (eventually_countable_ball hSc).2 fun s hs ↦ (h _ (hSp _ hs))
  filter_upwards [H, hf, hg] with x hx hxf hxg using hS _ hxf _ hxg hx

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

Goal state before:
pp: α : Type u_1
β : Type u_2
inst✝¹ : MeasurableSpace α
inst✝ : Countable α
s : Set α
hs : MeasurableSet s
this : s = ⋃ y ∈ s, measurableAtom y
⊢ MeasurableSet (⋃ y ∈ s, measurableAtom y)

Tactic:
apply MeasurableSet.biUnion (to_countable s) (fun x _hx ↦ ?_)

Goal state after:
α : Type u_1
β : Type u_2
inst✝¹ : MeasurableSpace α
inst✝ : Countable α
s : Set α
hs : MeasurableSet s
this : s = ⋃ y ∈ s, measurableAtom y
x : α
_hx : x ∈ s
⊢ MeasurableSet (measurableAtom x)
Module: Mathlib.MeasureTheory.MeasurableSpace.CountablyGenerated

Goal state before:
pp: case refine_3
α : Type u_1
mα : MeasurableSpace α
inst✝ : CountablyGenerated α
s : Set α
hs : MeasurableSet s
t : Set α
ht : MeasurableSet t
q : (ℕ → Prop) → Prop
htq : t = ⋃ p, if q p then countablyGeneratedAtom α p else ∅
⊢ ∃ q, tᶜ = ⋃ p, if q p then countablyGeneratedAtom α p else ∅

Tactic:
refine ⟨fun p ↦ ¬ q p, ?_⟩

Goal state after:
case refine_3
α : Type u_1
mα : MeasurableSpace α
inst✝ : CountablyGenerated α
s : Set α
hs : MeasurableSet s
t : Set α
ht : MeasurableSet t
q : (ℕ → Prop) → Prop
htq : t = ⋃ p, if q p then countablyGeneratedAtom α p else ∅
⊢ tᶜ = ⋃ p, if (fun p ↦ ¬q p) p then countablyGeneratedAtom α p else ∅
Module: Mathlib.MeasureTheory.Measure.Restrict

Goal state before:
pp: 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
i : ι
C : Finset ι
hiC : i ∈ C
x : α
hx : x ∈ P C
⊢ x ∈ s i

Tactic:
simp only [P, mem_inter_iff, mem_iInter] at hx

Goal state after:
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
i : ι
C : Finset ι
hiC : i ∈ C
x : α
hx : (∀ i ∈ C, x ∈ s i) ∧ ∀ i ∈ F \ C, x ∈ (s i)ᶜ
⊢ x ∈ s i
Module: Mathlib.MeasureTheory.MeasurableSpace.CountablyGenerated

Goal state before:
pp: case refine_1.succ
α : Type u_1
t : ℕ → Set α
n : ℕ
ih : ∀ u ∈ memPartition t n, MeasurableSet u
u : Set α
hun : ∃ u_1 ∈ memPartition t n, u = u_1 ∩ t n ∨ u = u_1 \ t n
⊢ MeasurableSet u

Tactic:
obtain ⟨v, hv, huv⟩ := hun

Goal state after:
case refine_1.succ
α : Type u_1
t : ℕ → Set α
n : ℕ
ih : ∀ u ∈ memPartition t n, MeasurableSet u
u v : Set α
hv : v ∈ memPartition t n
huv : u = v ∩ t n ∨ u = v \ t n
⊢ MeasurableSet u
Module: Mathlib.MeasureTheory.Order.Lattice

Goal state before:
pp: α : Type u_2
m : MeasurableSpace α
δ : Type u_3
inst✝² : MeasurableSpace δ
inst✝¹ : SemilatticeSup α
inst✝ : MeasurableSup₂ α
f : ℕ → δ → α
n : ℕ
hf : ∀ k ≤ n, Measurable (f k)
⊢ Measurable fun x ↦ (range (n + 1)).sup' ⋯ fun k ↦ f k x

Tactic:
convert! Finset.measurable_range_sup' hf using 1
  ext x
  simp

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

Goal state before:
pp: case refine_2.refine_2
α : Type u_1
m0 : MeasurableSpace α
μ ν : Measure α
s : Set α
hs : MeasurableSet s
t' : ℕ → Set α
ht' : s ⊆ iUnion t'
t : Set α := ⋃ n ∈ {k | μ (t' k) ≤ ν (t' k)}, t' n
ht : t = ⋃ n ∈ {k | μ (t' k) ≤ ν (t' k)}, t' n
hle₁ : μ (t ∩ s) ≤ ∑' (n : ↑{k | μ (t' k) ≤ ν (t' k)}), μ (t' ↑n)
hcap : tᶜ ∩ s ⊆ ⋃ n ∈ {k | ν (t' k) < μ (t' k)}, t' n
hle₂ : ν (tᶜ ∩ s) ≤ ∑' (n : ↑{k | ν (t' k) < μ (t' k)}), ν (t' ↑n)
heq : {k | μ (t' k) ≤ ν (t' k)} ∪ {k | ν (t' k) < μ (t' k)} = univ
n : ℕ
hn✝ : n ∈ {k | ν (t' k) < μ (t' k)}
hn : ν (t' n) < μ (t' n)
⊢ ν (t' ↑⟨n, hn✝⟩) = min (μ (t' ↑⟨n, hn✝⟩)) (ν (t' ↑⟨n, hn✝⟩))

Tactic:
simp [le_of_lt hn]

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

Goal state before:
pp: case refine_2
α : Type u_2
β : Type u_3
m0 : MeasurableSpace α
μ : Measure α
f : α → β
a✝ : Nontrivial β
inhabited_h : Inhabited β
S : Set (Set β)
hSc : S.Countable
hc : MeasurableSpace.CountablyGenerated β
h : NullMeasurable f μ
T : Set β → Set α
hTf : ∀ s ∈ S, T s ⊆ f ⁻¹' s
hTm : ∀ s ∈ S, MeasurableSet (T s)
hTeq : ∀ s ∈ S, T s =ᵐ[μ] f ⁻¹' s
U : Set β → Set α
hUf : ∀ s ∈ S, U s ⊇ f ⁻¹' s
hUm : ∀ s ∈ S, MeasurableSet (U s)
hUeq : ∀ s ∈ S, U s =ᵐ[μ] f ⁻¹' s
v : Set α := ⋃ s ∈ S, U s \ T s
hvm : MeasurableSet v
hvμ : μ v = 0
s : Set β
hs : s ∈ S
⊢ MeasurableSet (vᶜ ∩ f ⁻¹' s)

Tactic:
convert! (hTm s hs).diff hvm using 1

Goal state after:
α : Type u_2
β : Type u_3
m0 : MeasurableSpace α
μ : Measure α
f : α → β
a✝ : Nontrivial β
inhabited_h : Inhabited β
S : Set (Set β)
hSc : S.Countable
hc : MeasurableSpace.CountablyGenerated β
h : NullMeasurable f μ
T : Set β → Set α
hTf : ∀ s ∈ S, T s ⊆ f ⁻¹' s
hTm : ∀ s ∈ S, MeasurableSet (T s)
hTeq : ∀ s ∈ S, T s =ᵐ[μ] f ⁻¹' s
U : Set β → Set α
hUf : ∀ s ∈ S, U s ⊇ f ⁻¹' s
hUm : ∀ s ∈ S, MeasurableSet (U s)
hUeq : ∀ s ∈ S, U s =ᵐ[μ] f ⁻¹' s
v : Set α := ⋃ s ∈ S, U s \ T s
hvm : MeasurableSet v
hvμ : μ v = 0
s : Set β
hs : s ∈ S
⊢ vᶜ ∩ f ⁻¹' s = T s \ v
Module: Mathlib.MeasureTheory.Group.Arithmetic

Goal state before:
pp: α : Type u_1
G : Type u_2
inst✝³ : MeasurableSpace G
inst✝² : DivInvMonoid G
inst✝¹ : MeasurableMul G
inst✝ : MeasurableInv G
c : G
⊢ Measurable fun x ↦ x / c

Tactic:
convert! measurable_id.mul_const c⁻¹ using 1
    ext1
    apply div_eq_mul_inv

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

Goal state before:
pp: case sUnion
α : Type u_1
s : Set (Set α)
t : TopologicalSpace α
inst✝ : SecondCountableTopology α
hs : t = TopologicalSpace.generateFrom s
u : Set α
f : Set (Set α)
hf : ∀ s_1 ∈ f, GenerateOpen s s_1
ih : ∀ s_1 ∈ f, MeasurableSet s_1
⊢ MeasurableSet (⋃₀ f)

Tactic:
| sUnion f hf ih =>

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✝⁴ : Countable α
inst✝³ : MeasurableSpace α
inst✝² : MeasurableSingletonClass α
inst✝¹ : TopologicalSpace α
inst✝ : DiscreteTopology α
⊢ BorelSpace α

Tactic:
have : ∀ s, @MeasurableSet α inferInstance s := fun s ↦ s.to_countable.measurableSet

Goal state after:
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✝⁴ : Countable α
inst✝³ : MeasurableSpace α
inst✝² : MeasurableSingletonClass α
inst✝¹ : TopologicalSpace α
inst✝ : DiscreteTopology α
this : ∀ (s : Set α), MeasurableSet s
⊢ BorelSpace α
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✝
α : Type u_6
inst✝³ : TopologicalSpace α
inst✝² : MeasurableSpace α
inst✝¹ : BorelSpace α
inst✝ : SecondCountableTopology α
b : Set (Set α)
bct : b.Countable
hb : IsTopologicalBasis b
⊢ CountablyGenerated α

Tactic:
refine ⟨⟨b, bct, ?_⟩⟩

Goal state after:
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✝
α : Type u_6
inst✝³ : TopologicalSpace α
inst✝² : MeasurableSpace α
inst✝¹ : BorelSpace α
inst✝ : SecondCountableTopology α
b : Set (Set α)
bct : b.Countable
hb : IsTopologicalBasis b
⊢ inst✝² = MeasurableSpace.generateFrom b
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✝¹² : TopologicalSpace α
inst✝¹¹ : MeasurableSpace α
inst✝¹⁰ : OpensMeasurableSpace α
inst✝⁹ : TopologicalSpace β
inst✝⁸ : MeasurableSpace β
inst✝⁷ : OpensMeasurableSpace β
inst✝⁶ : TopologicalSpace γ
inst✝⁵ : MeasurableSpace γ
inst✝⁴ : BorelSpace γ
inst✝³ : TopologicalSpace γ₂
inst✝² : MeasurableSpace γ₂
inst✝¹ : BorelSpace γ₂
inst✝ : MeasurableSpace δ
a : α
⊢ (𝓝 a).IsMeasurablyGenerated

Tactic:
nhds,

Goal state after:
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✝¹² : TopologicalSpace α
inst✝¹¹ : MeasurableSpace α
inst✝¹⁰ : OpensMeasurableSpace α
inst✝⁹ : TopologicalSpace β
inst✝⁸ : MeasurableSpace β
inst✝⁷ : OpensMeasurableSpace β
inst✝⁶ : TopologicalSpace γ
inst✝⁵ : MeasurableSpace γ
inst✝⁴ : BorelSpace γ
inst✝³ : TopologicalSpace γ₂
inst✝² : MeasurableSpace γ₂
inst✝¹ : BorelSpace γ₂
inst✝ : MeasurableSpace δ
a : α
⊢ (⨅ s ∈ {s | a ∈ s ∧ IsOpen[inst✝¹²] s}, 𝓟 s).IsMeasurablyGenerated
Module: Mathlib.MeasureTheory.Constructions.BorelSpace.Order

Goal state before:
pp: case refine_1.inl
α : Type u_1
inst✝³ : TopologicalSpace α
inst✝² : SecondCountableTopology α
inst✝¹ : LinearOrder α
inst✝ : OrderTopology α
this : MeasurableSpace α := MeasurableSpace.generateFrom (range Iio)
H : ∀ (a : α), MeasurableSet (Iio a)
a : α
⊢ MeasurableSet (Ioi a)

pp: case refine_1.inr
α : Type u_1
inst✝³ : TopologicalSpace α
inst✝² : SecondCountableTopology α
inst✝¹ : LinearOrder α
inst✝ : OrderTopology α
this : MeasurableSpace α := MeasurableSpace.generateFrom (range Iio)
H : ∀ (a : α), MeasurableSet (Iio a)
a : α
⊢ MeasurableSet (Iio a)

Tactic:
· rcases em (∃ b, a ⋖ b) with ⟨b, hb⟩ | hcovBy
      · rw [hb.Ioi_eq, ← compl_Iio]
        exact (H _).compl
      · rcases isOpen_biUnion_countable (Ioi a) Ioi fun _ _ ↦ isOpen_Ioi with ⟨t, hat, htc, htU⟩
        have : Ioi a = ⋃ b ∈ t, Ici b := by
          refine Subset.antisymm ?_ <| iUnion₂_subset fun b hb ↦ Ici_subset_Ioi.2 (hat hb)
          refine Subset.trans ?_ <| iUnion₂_mono fun _ _ ↦ Ioi_subset_Ici_self
          simpa [CovBy, htU, subset_def] using hcovBy
        simp only [this, ← compl_Iio]
        exact .biUnion htc <| fun _ _ ↦ (H _).compl

Goal state after:
case refine_1.inr
α : Type u_1
inst✝³ : TopologicalSpace α
inst✝² : SecondCountableTopology α
inst✝¹ : LinearOrder α
inst✝ : OrderTopology α
this : MeasurableSpace α := MeasurableSpace.generateFrom (range Iio)
H : ∀ (a : α), MeasurableSet (Iio a)
a : α
⊢ MeasurableSet (Iio a)
Module: Mathlib.MeasureTheory.Constructions.BorelSpace.Order

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

Tactic:
· refine MeasurableSet.biUnion hc fun a ha => MeasurableSet.biUnion hc fun b hb => ?_
      refine MeasurableSet.iUnion fun hab => MeasurableSet.iUnion fun _ => ?_
      exact .basic _ ⟨a, hts ha, b, hts hb, hab.le, mem_singleton _⟩

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

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

Tactic:
have hbs : b ∈ s := hIoo b a ba hb

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

Goal state before:
pp: α : Type u_6
β : Type u_7
inst✝³ : MeasurableSpace α
inst✝² : TopologicalSpace α
inst✝¹ : MeasurableSpace β
inst✝ : TopologicalSpace β
hβ : BorelSpace β
e : α → β
h'e : MeasurableEmbedding e
h''e : IsInducing e
this : MeasurableSpace.comap e (borel β) = inst✝³
⊢ borel α = borel α

Tactic:
h''e.eq_induced

Goal state after:
α : Type u_6
β : Type u_7
inst✝³ : MeasurableSpace α
inst✝² : TopologicalSpace α
inst✝¹ : MeasurableSpace β
inst✝ : TopologicalSpace β
hβ : BorelSpace β
e : α → β
h'e : MeasurableEmbedding e
h''e : IsInducing e
this : MeasurableSpace.comap e (borel β) = inst✝³
⊢ borel α = borel α
Module: Mathlib.Topology.MetricSpace.Thickening

Goal state before:
pp: α : Type u
inst✝ : PseudoEMetricSpace α
s t : Set α
hst : Disjoint s t
hs : IsCompact s
ht : IsClosed[PseudoEMetricSpace.toUniformSpace.toTopologicalSpace] t
r : ℝ≥0
hr : 0 < r
h : ∀ x ∈ s, ∀ y ∈ t, ↑r < edist x y
z : α
hzs : z ∈ thickening (↑r / 2) s
hzt : z ∈ thickening (↑r / 2) t
⊢ z ∈ ⊥

Tactic:
mem_thickening_iff_exists_edist_lt

Goal state after:
α : Type u
inst✝ : PseudoEMetricSpace α
s t : Set α
hst : Disjoint s t
hs : IsCompact s
ht : IsClosed[PseudoEMetricSpace.toUniformSpace.toTopologicalSpace] t
r : ℝ≥0
hr : 0 < r
h : ∀ x ∈ s, ∀ y ∈ t, ↑r < edist x y
z : α
hzs : ∃ z_1 ∈ s, edist z z_1 < ENNReal.ofReal (↑r / 2)
hzt : ∃ z_1 ∈ t, edist z z_1 < ENNReal.ofReal (↑r / 2)
⊢ z ∈ ⊥
Module: Mathlib.Topology.MetricSpace.Thickening

Goal state before:
pp: α : Type u_2
inst✝ : PseudoMetricSpace α
x : α
E : Set α
hx : x ∈ E
δ : ℝ
⊢ closedBall x δ ⊆ cthickening δ E

Tactic:
by
  refine (closedBall_subset_cthickening_singleton _ _).trans (cthickening_subset_of_subset _ ?_)
  simpa using hx

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

Goal state before:
pp: case a
α : Type u_3
β : Type u_4
C : Set (Set α)
D : Set (Set β)
hC : IsCountablySpanning C
hD : IsCountablySpanning D
⊢ ∀ t ∈ image2 (fun x1 x2 ↦ x1 ×ˢ x2) C D, MeasurableSet t

Tactic:
rintro _ ⟨s, hs, t, ht, rfl⟩

Goal state after:
case a
α : Type u_3
β : Type u_4
C : Set (Set α)
D : Set (Set β)
hC : IsCountablySpanning C
hD : IsCountablySpanning D
s : Set α
hs : s ∈ C
t : Set β
ht : t ∈ D
⊢ MeasurableSet ((fun x1 x2 ↦ x1 ×ˢ x2) s t)
Module: Mathlib.MeasureTheory.Constructions.BorelSpace.Order

Goal state before:
pp: case inl.inr
α : Type u_1
δ : Type u_4
inst✝⁵ : TopologicalSpace α
mα : MeasurableSpace α
inst✝⁴ : BorelSpace α
mδ : MeasurableSpace δ
inst✝³ : LinearOrder α
inst✝² : OrderTopology α
inst✝¹ : SecondCountableTopology α
ι : Sort u_5
inst✝ : Countable ι
f : ι → δ → α
g g' : δ → α
hf : ∀ (i : ι), Measurable (f i)
s : Set δ
hs : MeasurableSet s
hg : ∀ b ∈ s, IsLUB {a | ∃ i, f i b = a} (g b)
hg' : EqOn g g' sᶜ
g'_meas : Measurable g'
hι : IsEmpty ι
x : δ
hx : x ∈ s
A : ∀ b ∈ s, IsBot (g b)
B : ∀ b ∈ s, g b = g x
this : g = s.piecewise (fun _y ↦ g x) g'
⊢ Measurable (s.piecewise (fun _y ↦ g x) g')

Tactic:
exact Measurable.piecewise hs measurable_const g'_meas

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

Goal state before:
pp: α : Type u_1
inst✝ : MeasurableSpace α
f : α → ℝ≥0∞
hf : Measurable f
a : α
⊢ ∑' (n : ℕ), ↑((eapproxDiff f n) a) = f a

Tactic:
ENNReal.tsum_eq_iSup_nat' (tendsto_add_atTop_nat 1),

Goal state after:
α : Type u_1
inst✝ : MeasurableSpace α
f : α → ℝ≥0∞
hf : Measurable f
a : α
⊢ ⨆ i, ∑ n ∈ Finset.range (i + 1), ↑((eapproxDiff f n) a) = f a
Module: Mathlib.MeasureTheory.Constructions.BorelSpace.Order

Goal state before:
pp: case pos
α : Type u_1
δ : Type u_4
inst✝⁵ : TopologicalSpace α
mα : MeasurableSpace α
inst✝⁴ : BorelSpace α
mδ : MeasurableSpace δ
inst✝³ : LinearOrder α
inst✝² : OrderTopology α
inst✝¹ : SecondCountableTopology α
ι : Sort u_5
μ : Measure δ
inst✝ : Countable ι
f : ι → δ → α
g : δ → α
hf : ∀ (i : ι), AEMeasurable (f i) μ
hg : ∀ᵐ (b : δ) ∂μ, IsLUB {a | ∃ i, f i b = a} (g b)
a✝ : Nontrivial α
hα : Nonempty α
hι : Nonempty ι
p : δ → (ι → α) → Prop := fun x f' ↦ IsLUB {a | ∃ i, f' i = a} (g x)
g_seq : δ → α := (aeSeqSet hf p).piecewise g fun x ↦ hα.some
b : δ
h : b ∈ aeSeqSet hf p
h_set_eq : {a | ∃ i, mk (f i) ⋯ b = a} = {a | ∃ i, f i b = a}
⊢ IsLUB {a | ∃ i, f i b = a} (g b)

Tactic:
exact aeSeq.fun_prop_of_mem_aeSeqSet hf h

Goal state after: