Theorem: ContinuousMap.summable_of_locally_summable_norm
File: Mathlib/Topology/ContinuousFunction/Compact.lean

Proof steps:
state_before: X : Type u_1
inst✝⁴ : TopologicalSpace X
inst✝³ : T2Space X
inst✝² : LocallyCompactSpace X
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : CompleteSpace E
ι : Type u_3
F : ι → C(X, E)
hF : ∀ (K : Compacts X), Summable fun i => ‖restrict (↑K) (F i)‖
⊢ Summable F
state_after: X : Type u_1
inst✝⁴ : TopologicalSpace X
inst✝³ : T2Space X
inst✝² : LocallyCompactSpace X
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : CompleteSpace E
ι : Type u_3
F : ι → C(X, E)
hF : ∀ (K : Compacts X), Summable fun i => ‖restrict (↑K) (F i)‖
K : Set X
hK : IsCompact K
⊢ ∃ f, Tendsto (fun i => restrict K (∑ b ∈ i, F b)) atTop (𝓝 f)
tactic: refine (ContinuousMap.exists_tendsto_compactOpen_iff_forall _).2 fun K hK => ?_
state_before: X : Type u_1
inst✝⁴ : TopologicalSpace X
inst✝³ : T2Space X
inst✝² : LocallyCompactSpace X
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : CompleteSpace E
ι : Type u_3
F : ι → C(X, E)
hF : ∀ (K : Compacts X), Summable fun i => ‖restrict (↑K) (F i)‖
K : Set X
hK : IsCompact K
⊢ ∃ f, Tendsto (fun i => restrict K (∑ b ∈ i, F b)) atTop (𝓝 f)
state_after: case intro
X : Type u_1
inst✝⁴ : TopologicalSpace X
inst✝³ : T2Space X
inst✝² : LocallyCompactSpace X
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : CompleteSpace E
ι : Type u_3
F : ι → C(X, E)
hF : ∀ (K : Compacts X), Summable fun i => ‖restrict (↑K) (F i)‖
K : Compacts X
⊢ ∃ f, Tendsto (fun i => restrict (↑K) (∑ b ∈ i, F b)) atTop (𝓝 f)
tactic: lift K to Compacts X using hK
state_before: case intro
X : Type u_1
inst✝⁴ : TopologicalSpace X
inst✝³ : T2Space X
inst✝² : LocallyCompactSpace X
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : CompleteSpace E
ι : Type u_3
F : ι → C(X, E)
hF : ∀ (K : Compacts X), Summable fun i => ‖restrict (↑K) (F i)‖
K : Compacts X
⊢ ∃ f, Tendsto (fun i => restrict (↑K) (∑ b ∈ i, F b)) atTop (𝓝 f)
state_after: case intro
X : Type u_1
inst✝⁴ : TopologicalSpace X
inst✝³ : T2Space X
inst✝² : LocallyCompactSpace X
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : CompleteSpace E
ι : Type u_3
F : ι → C(X, E)
hF : ∀ (K : Compacts X), Summable fun i => ‖restrict (↑K) (F i)‖
K : Compacts X
A : ∀ (s : Finset ι), restrict (↑K) (∑ i ∈ s, F i) = ∑ i ∈ s, restrict (↑K) (F i)
⊢ ∃ f, Tendsto (fun i => restrict (↑K) (∑ b ∈ i, F b)) atTop (𝓝 f)
tactic: have A : ∀ s : Finset ι, restrict (↑K) (∑ i ∈ s, F i) = ∑ i ∈ s, restrict K (F i) := by
    intro s
    ext1 x
    simp
    -- This used to be the end of the proof before leanprover/lean4#2644
    erw [restrict_apply, restrict_apply, restrict_apply, restrict_apply]
    simp? says simp only [coe_sum, Finset.sum_apply]
    congr!
state_before: case intro
X : Type u_1
inst✝⁴ : TopologicalSpace X
inst✝³ : T2Space X
inst✝² : LocallyCompactSpace X
E : Type u_2
inst✝¹ : NormedAddCommGroup E
inst✝ : CompleteSpace E
ι : Type u_3
F : ι → C(X, E)
hF : ∀ (K : Compacts X), Summable fun i => ‖restrict (↑K) (F i)‖
K : Compacts X
A : ∀ (s : Finset ι), restrict (↑K) (∑ i ∈ s, F i) = ∑ i ∈ s, restrict (↑K) (F i)
⊢ ∃ f, Tendsto (fun i => restrict (↑K) (∑ b ∈ i, F b)) atTop (𝓝 f)
state_after: no goals
tactic: simpa only [HasSum, A] using (hF K).of_norm