Theorem: measurableSet_bddAbove_range
File: Mathlib/MeasureTheory/Constructions/BorelSpace/Order.lean

Proof steps:
state_before: α : Type u_1
β : Type u_2
γ : Type u_3
δ : Type u_4
ι✝ : Sort y
s t u : Set α
inst✝¹⁰ : TopologicalSpace α
inst✝⁹ : MeasurableSpace α
inst✝⁸ : BorelSpace α
inst✝⁷ : TopologicalSpace β
inst✝⁶ : MeasurableSpace β
inst✝⁵ : BorelSpace β
inst✝⁴ : 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
hf : ∀ (i : ι), Measurable (f i)
⊢ MeasurableSet {b | BddAbove (range fun i => f i b)}
state_after: case inl
α : Type u_1
β : Type u_2
γ : Type u_3
δ : Type u_4
ι✝ : Sort y
s t u : Set α
inst✝¹⁰ : TopologicalSpace α
inst✝⁹ : MeasurableSpace α
inst✝⁸ : BorelSpace α
inst✝⁷ : TopologicalSpace β
inst✝⁶ : MeasurableSpace β
inst✝⁵ : BorelSpace β
inst✝⁴ : 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
hf : ∀ (i : ι), Measurable (f i)
hα : IsEmpty α
⊢ MeasurableSet {b | BddAbove (range fun i => f i b)}

case inr
α : Type u_1
β : Type u_2
γ : Type u_3
δ : Type u_4
ι✝ : Sort y
s t u : Set α
inst✝¹⁰ : TopologicalSpace α
inst✝⁹ : MeasurableSpace α
inst✝⁸ : BorelSpace α
inst✝⁷ : TopologicalSpace β
inst✝⁶ : MeasurableSpace β
inst✝⁵ : BorelSpace β
inst✝⁴ : 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
hf : ∀ (i : ι), Measurable (f i)
hα : Nonempty α
⊢ MeasurableSet {b | BddAbove (range fun i => f i b)}
tactic: rcases isEmpty_or_nonempty α with hα|hα
state_before: case inr
α : Type u_1
β : Type u_2
γ : Type u_3
δ : Type u_4
ι✝ : Sort y
s t u : Set α
inst✝¹⁰ : TopologicalSpace α
inst✝⁹ : MeasurableSpace α
inst✝⁸ : BorelSpace α
inst✝⁷ : TopologicalSpace β
inst✝⁶ : MeasurableSpace β
inst✝⁵ : BorelSpace β
inst✝⁴ : 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
hf : ∀ (i : ι), Measurable (f i)
hα : Nonempty α
⊢ MeasurableSet {b | BddAbove (range fun i => f i b)}
state_after: case inr
α : Type u_1
β : Type u_2
γ : Type u_3
δ : Type u_4
ι✝ : Sort y
s t u : Set α
inst✝¹⁰ : TopologicalSpace α
inst✝⁹ : MeasurableSpace α
inst✝⁸ : BorelSpace α
inst✝⁷ : TopologicalSpace β
inst✝⁶ : MeasurableSpace β
inst✝⁵ : BorelSpace β
inst✝⁴ : 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
hf : ∀ (i : ι), Measurable (f i)
hα : Nonempty α
A : ∀ (i : ι) (c : α), MeasurableSet {x | f i x ≤ c}
⊢ MeasurableSet {b | BddAbove (range fun i => f i b)}
tactic: have A : ∀ (i : ι) (c : α), MeasurableSet {x | f i x ≤ c} := by
    intro i c
    exact measurableSet_le (hf i) measurable_const
state_before: case inr
α : Type u_1
β : Type u_2
γ : Type u_3
δ : Type u_4
ι✝ : Sort y
s t u : Set α
inst✝¹⁰ : TopologicalSpace α
inst✝⁹ : MeasurableSpace α
inst✝⁸ : BorelSpace α
inst✝⁷ : TopologicalSpace β
inst✝⁶ : MeasurableSpace β
inst✝⁵ : BorelSpace β
inst✝⁴ : 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
hf : ∀ (i : ι), Measurable (f i)
hα : Nonempty α
A : ∀ (i : ι) (c : α), MeasurableSet {x | f i x ≤ c}
⊢ MeasurableSet {b | BddAbove (range fun i => f i b)}
state_after: case inr
α : Type u_1
β : Type u_2
γ : Type u_3
δ : Type u_4
ι✝ : Sort y
s t u : Set α
inst✝¹⁰ : TopologicalSpace α
inst✝⁹ : MeasurableSpace α
inst✝⁸ : BorelSpace α
inst✝⁷ : TopologicalSpace β
inst✝⁶ : MeasurableSpace β
inst✝⁵ : BorelSpace β
inst✝⁴ : 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
hf : ∀ (i : ι), Measurable (f i)
hα : Nonempty α
A : ∀ (i : ι) (c : α), MeasurableSet {x | f i x ≤ c}
B : ∀ (c : α), MeasurableSet {x | ∀ (i : ι), f i x ≤ c}
⊢ MeasurableSet {b | BddAbove (range fun i => f i b)}
tactic: have B : ∀ (c : α), MeasurableSet {x | ∀ i, f i x ≤ c} := by
    intro c
    rw [setOf_forall]
    exact MeasurableSet.iInter (fun i ↦ A i c)
state_before: case inr
α : Type u_1
β : Type u_2
γ : Type u_3
δ : Type u_4
ι✝ : Sort y
s t u : Set α
inst✝¹⁰ : TopologicalSpace α
inst✝⁹ : MeasurableSpace α
inst✝⁸ : BorelSpace α
inst✝⁷ : TopologicalSpace β
inst✝⁶ : MeasurableSpace β
inst✝⁵ : BorelSpace β
inst✝⁴ : 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
hf : ∀ (i : ι), Measurable (f i)
hα : Nonempty α
A : ∀ (i : ι) (c : α), MeasurableSet {x | f i x ≤ c}
B : ∀ (c : α), MeasurableSet {x | ∀ (i : ι), f i x ≤ c}
⊢ MeasurableSet {b | BddAbove (range fun i => f i b)}
state_after: case inr.intro
α : Type u_1
β : Type u_2
γ : Type u_3
δ : Type u_4
ι✝ : Sort y
s t u✝ : Set α
inst✝¹⁰ : TopologicalSpace α
inst✝⁹ : MeasurableSpace α
inst✝⁸ : BorelSpace α
inst✝⁷ : TopologicalSpace β
inst✝⁶ : MeasurableSpace β
inst✝⁵ : BorelSpace β
inst✝⁴ : 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
hf : ∀ (i : ι), Measurable (f i)
hα : Nonempty α
A : ∀ (i : ι) (c : α), MeasurableSet {x | f i x ≤ c}
B : ∀ (c : α), MeasurableSet {x | ∀ (i : ι), f i x ≤ c}
u : ℕ → α
hu : Tendsto u atTop atTop
⊢ MeasurableSet {b | BddAbove (range fun i => f i b)}
tactic: obtain ⟨u, hu⟩ : ∃ (u : ℕ → α), Tendsto u atTop atTop := exists_seq_tendsto (atTop : Filter α)
state_before: case inr.intro
α : Type u_1
β : Type u_2
γ : Type u_3
δ : Type u_4
ι✝ : Sort y
s t u✝ : Set α
inst✝¹⁰ : TopologicalSpace α
inst✝⁹ : MeasurableSpace α
inst✝⁸ : BorelSpace α
inst✝⁷ : TopologicalSpace β
inst✝⁶ : MeasurableSpace β
inst✝⁵ : BorelSpace β
inst✝⁴ : 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
hf : ∀ (i : ι), Measurable (f i)
hα : Nonempty α
A : ∀ (i : ι) (c : α), MeasurableSet {x | f i x ≤ c}
B : ∀ (c : α), MeasurableSet {x | ∀ (i : ι), f i x ≤ c}
u : ℕ → α
hu : Tendsto u atTop atTop
this : {b | BddAbove (range fun i => f i b)} = {x | ∃ n, ∀ (i : ι), f i x ≤ u n}
⊢ MeasurableSet {b | BddAbove (range fun i => f i b)}
state_after: case inr.intro
α : Type u_1
β : Type u_2
γ : Type u_3
δ : Type u_4
ι✝ : Sort y
s t u✝ : Set α
inst✝¹⁰ : TopologicalSpace α
inst✝⁹ : MeasurableSpace α
inst✝⁸ : BorelSpace α
inst✝⁷ : TopologicalSpace β
inst✝⁶ : MeasurableSpace β
inst✝⁵ : BorelSpace β
inst✝⁴ : 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
hf : ∀ (i : ι), Measurable (f i)
hα : Nonempty α
A : ∀ (i : ι) (c : α), MeasurableSet {x | f i x ≤ c}
B : ∀ (c : α), MeasurableSet {x | ∀ (i : ι), f i x ≤ c}
u : ℕ → α
hu : Tendsto u atTop atTop
this : {b | BddAbove (range fun i => f i b)} = {x | ∃ n, ∀ (i : ι), f i x ≤ u n}
⊢ MeasurableSet (⋃ i, {x | ∀ (i_1 : ι), f i_1 x ≤ u i})
tactic: rw [this, setOf_exists]
state_before: case inr.intro
α : Type u_1
β : Type u_2
γ : Type u_3
δ : Type u_4
ι✝ : Sort y
s t u✝ : Set α
inst✝¹⁰ : TopologicalSpace α
inst✝⁹ : MeasurableSpace α
inst✝⁸ : BorelSpace α
inst✝⁷ : TopologicalSpace β
inst✝⁶ : MeasurableSpace β
inst✝⁵ : BorelSpace β
inst✝⁴ : 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
hf : ∀ (i : ι), Measurable (f i)
hα : Nonempty α
A : ∀ (i : ι) (c : α), MeasurableSet {x | f i x ≤ c}
B : ∀ (c : α), MeasurableSet {x | ∀ (i : ι), f i x ≤ c}
u : ℕ → α
hu : Tendsto u atTop atTop
this : {b | BddAbove (range fun i => f i b)} = {x | ∃ n, ∀ (i : ι), f i x ≤ u n}
⊢ MeasurableSet (⋃ i, {x | ∀ (i_1 : ι), f i_1 x ≤ u i})
state_after: no goals
tactic: exact MeasurableSet.iUnion (fun n ↦ B (u n))