Theorem: MeasureTheory.AnalyticSet.iUnion
File: Mathlib/MeasureTheory/Constructions/Polish/Basic.lean

Proof steps:
state_before: α : Type u_1
ι : Type u_2
inst✝¹ : TopologicalSpace α
inst✝ : Countable ι
s : ι → Set α
hs : ∀ (n : ι), AnalyticSet (s n)
⊢ AnalyticSet (⋃ n, s n)
state_after: α : Type u_1
ι : Type u_2
inst✝¹ : TopologicalSpace α
inst✝ : Countable ι
s : ι → Set α
hs : ∀ (n : ι), AnalyticSet (s n)
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 (f n)
f_range : ∀ (n : ι), range (f n) = s n
⊢ AnalyticSet (⋃ n, s n)
tactic: choose β hβ h'β f f_cont f_range using fun n =>
    analyticSet_iff_exists_polishSpace_range.1 (hs n)
state_before: α : Type u_1
ι : Type u_2
inst✝¹ : TopologicalSpace α
inst✝ : Countable ι
s : ι → Set α
hs : ∀ (n : ι), AnalyticSet (s n)
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 (f n)
f_range : ∀ (n : ι), range (f n) = s n
⊢ AnalyticSet (⋃ n, s n)
state_after: α : Type u_1
ι : Type u_2
inst✝¹ : TopologicalSpace α
inst✝ : Countable ι
s : ι → Set α
hs : ∀ (n : ι), AnalyticSet (s n)
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 (f n)
f_range : ∀ (n : ι), range (f n) = s n
γ : Type u_2 := (n : ι) × β n
⊢ AnalyticSet (⋃ n, s n)
tactic: let γ := Σn, β n
state_before: α : Type u_1
ι : Type u_2
inst✝¹ : TopologicalSpace α
inst✝ : Countable ι
s : ι → Set α
hs : ∀ (n : ι), AnalyticSet (s n)
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 (f n)
f_range : ∀ (n : ι), range (f n) = s n
γ : Type u_2 := (n : ι) × β n
⊢ AnalyticSet (⋃ n, s n)
state_after: α : Type u_1
ι : Type u_2
inst✝¹ : TopologicalSpace α
inst✝ : Countable ι
s : ι → Set α
hs : ∀ (n : ι), AnalyticSet (s n)
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 (f n)
f_range : ∀ (n : ι), range (f n) = s n
γ : Type u_2 := (n : ι) × β n
F : γ → α :=
  fun x =>
    match x with
    | ⟨n, x⟩ => f n x
⊢ AnalyticSet (⋃ n, s n)
tactic: let F : γ → α := fun ⟨n, x⟩ ↦ f n x
state_before: α : Type u_1
ι : Type u_2
inst✝¹ : TopologicalSpace α
inst✝ : Countable ι
s : ι → Set α
hs : ∀ (n : ι), AnalyticSet (s n)
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 (f n)
f_range : ∀ (n : ι), range (f n) = s n
γ : Type u_2 := (n : ι) × β n
F : γ → α :=
  fun x =>
    match x with
    | ⟨n, x⟩ => f n x
⊢ AnalyticSet (⋃ n, s n)
state_after: α : Type u_1
ι : Type u_2
inst✝¹ : TopologicalSpace α
inst✝ : Countable ι
s : ι → Set α
hs : ∀ (n : ι), AnalyticSet (s n)
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 (f n)
f_range : ∀ (n : ι), range (f n) = s n
γ : Type u_2 := (n : ι) × β n
F : γ → α :=
  fun x =>
    match x with
    | ⟨n, x⟩ => f n x
F_cont : Continuous F
⊢ AnalyticSet (⋃ n, s n)
tactic: have F_cont : Continuous F := continuous_sigma f_cont
state_before: α : Type u_1
ι : Type u_2
inst✝¹ : TopologicalSpace α
inst✝ : Countable ι
s : ι → Set α
hs : ∀ (n : ι), AnalyticSet (s n)
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 (f n)
f_range : ∀ (n : ι), range (f n) = s n
γ : Type u_2 := (n : ι) × β n
F : γ → α :=
  fun x =>
    match x with
    | ⟨n, x⟩ => f n x
F_cont : Continuous F
⊢ AnalyticSet (⋃ n, s n)
state_after: α : Type u_1
ι : Type u_2
inst✝¹ : TopologicalSpace α
inst✝ : Countable ι
s : ι → Set α
hs : ∀ (n : ι), AnalyticSet (s n)
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 (f n)
f_range : ∀ (n : ι), range (f n) = s n
γ : Type u_2 := (n : ι) × β n
F : γ → α :=
  fun x =>
    match x with
    | ⟨n, x⟩ => f n x
F_cont : Continuous F
F_range : range F = ⋃ n, s n
⊢ AnalyticSet (⋃ n, s n)
tactic: have F_range : range F = ⋃ n, s n := by
    simp only [γ, range_sigma_eq_iUnion_range, f_range]
state_before: α : Type u_1
ι : Type u_2
inst✝¹ : TopologicalSpace α
inst✝ : Countable ι
s : ι → Set α
hs : ∀ (n : ι), AnalyticSet (s n)
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 (f n)
f_range : ∀ (n : ι), range (f n) = s n
γ : Type u_2 := (n : ι) × β n
F : γ → α :=
  fun x =>
    match x with
    | ⟨n, x⟩ => f n x
F_cont : Continuous F
F_range : range F = ⋃ n, s n
⊢ AnalyticSet (⋃ n, s n)
state_after: α : Type u_1
ι : Type u_2
inst✝¹ : TopologicalSpace α
inst✝ : Countable ι
s : ι → Set α
hs : ∀ (n : ι), AnalyticSet (s n)
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 (f n)
f_range : ∀ (n : ι), range (f n) = s n
γ : Type u_2 := (n : ι) × β n
F : γ → α :=
  fun x =>
    match x with
    | ⟨n, x⟩ => f n x
F_cont : Continuous F
F_range : range F = ⋃ n, s n
⊢ AnalyticSet (range F)
tactic: rw [← F_range]
state_before: α : Type u_1
ι : Type u_2
inst✝¹ : TopologicalSpace α
inst✝ : Countable ι
s : ι → Set α
hs : ∀ (n : ι), AnalyticSet (s n)
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 (f n)
f_range : ∀ (n : ι), range (f n) = s n
γ : Type u_2 := (n : ι) × β n
F : γ → α :=
  fun x =>
    match x with
    | ⟨n, x⟩ => f n x
F_cont : Continuous F
F_range : range F = ⋃ n, s n
⊢ AnalyticSet (range F)
state_after: no goals
tactic: exact analyticSet_range_of_polishSpace F_cont