-- Mathlib/Topology/UniformSpace/Ascoli.lean
theorem Equicontinuous.tendsto_uniformFun_iff_pi [CompactSpace X]
    (F_eqcont : Equicontinuous F) (ℱ : Filter ι) (f : X → α) :
    Tendsto (UniformFun.ofFun ∘ F) ℱ (𝓝 <| UniformFun.ofFun f) ↔
    Tendsto F ℱ (𝓝 f)

Proof state:
ι : Type u_1
X : Type u_2
α : Type u_3
inst✝² : TopologicalSpace X
inst✝¹ : UniformSpace α
F : ι → X → α
inst✝ : CompactSpace X
F_eqcont : Equicontinuous F
ℱ : Filter ι
f : X → α
ℱ_ne : ℱ.NeBot
H : Tendsto F ℱ (𝓝 f)
S : Set (X → α) := closure (range F)
𝒢 : Filter ↑S := comap Subtype.val (map F ℱ)
⊢ Equicontinuous (id ∘ Subtype.val)

Tactic:
rwa [equicontinuous_iff_range] at F_eqcont

Result:
no goals

Proof state:
case inr.mpr
ι : Type u_1
X : Type u_2
α : Type u_3
inst✝² : TopologicalSpace X
inst✝¹ : UniformSpace α
F : ι → X → α
inst✝ : CompactSpace X
F_eqcont : Equicontinuous F
ℱ : Filter ι
f : X → α
ℱ_ne : ℱ.NeBot
H : Tendsto F ℱ (𝓝 f)
S : Set (X → α) := closure (range F)
𝒢 : Filter ↑S := comap Subtype.val (map F ℱ)
⊢ Tendsto (⇑UniformFun.ofFun ∘ F) ℱ (𝓝 (UniformFun.ofFun f))

Tactic:
have hS : S.Equicontinuous := closure' (by rwa [equicontinuous_iff_range] at F_eqcont)
  continuous_id

Result:
case inr.mpr
ι : Type u_1
X : Type u_2
α : Type u_3
inst✝² : TopologicalSpace X
inst✝¹ : UniformSpace α
F : ι → X → α
inst✝ : CompactSpace X
F_eqcont : Equicontinuous F
ℱ : Filter ι
f : X → α
ℱ_ne : ℱ.NeBot
H : Tendsto F ℱ (𝓝 f)
S : Set (X → α) := closure (range F)
𝒢 : Filter ↑S := comap Subtype.val (map F ℱ)
hS : S.Equicontinuous
⊢ Tendsto (⇑UniformFun.ofFun ∘ F) ℱ (𝓝 (UniformFun.ofFun f))

Proof state:
case inr.mpr
ι : Type u_1
X : Type u_2
α : Type u_3
inst✝² : TopologicalSpace X
inst✝¹ : UniformSpace α
F : ι → X → α
inst✝ : CompactSpace X
F_eqcont : Equicontinuous F
ℱ : Filter ι
f : X → α
ℱ_ne : ℱ.NeBot
H : Tendsto F ℱ (𝓝 f)
S : Set (X → α) := closure (range F)
⊢ Tendsto (⇑UniformFun.ofFun ∘ F) ℱ (𝓝 (UniformFun.ofFun f))

Tactic:
set 𝒢 : Filter S := comap (↑) (map F ℱ)

Result:
case inr.mpr
ι : Type u_1
X : Type u_2
α : Type u_3
inst✝² : TopologicalSpace X
inst✝¹ : UniformSpace α
F : ι → X → α
inst✝ : CompactSpace X
F_eqcont : Equicontinuous F
ℱ : Filter ι
f : X → α
ℱ_ne : ℱ.NeBot
H : Tendsto F ℱ (𝓝 f)
S : Set (X → α) := closure (range F)
𝒢 : Filter ↑S := comap Subtype.val (map F ℱ)
⊢ Tendsto (⇑UniformFun.ofFun ∘ F) ℱ (𝓝 (UniformFun.ofFun f))

Proof state:
case inl
ι : Type u_1
X : Type u_2
α : Type u_3
inst✝² : TopologicalSpace X
inst✝¹ : UniformSpace α
F : ι → X → α
inst✝ : CompactSpace X
F_eqcont : Equicontinuous F
f : X → α
⊢ Tendsto (⇑UniformFun.ofFun ∘ F) ⊥ (𝓝 (UniformFun.ofFun f)) ↔ Tendsto F ⊥ (𝓝 f)

Tactic:
simp

Result:
no goals

Proof state:
case inr
ι : Type u_1
X : Type u_2
α : Type u_3
inst✝² : TopologicalSpace X
inst✝¹ : UniformSpace α
F : ι → X → α
inst✝ : CompactSpace X
F_eqcont : Equicontinuous F
ℱ : Filter ι
f : X → α
ℱ_ne : ℱ.NeBot
⊢ Tendsto (⇑UniformFun.ofFun ∘ F) ℱ (𝓝 (UniformFun.ofFun f)) ↔ Tendsto F ℱ (𝓝 f)

Tactic:
constructor <;> intro H

Result:
case inr.mp
ι : Type u_1
X : Type u_2
α : Type u_3
inst✝² : TopologicalSpace X
inst✝¹ : UniformSpace α
F : ι → X → α
inst✝ : CompactSpace X
F_eqcont : Equicontinuous F
ℱ : Filter ι
f : X → α
ℱ_ne : ℱ.NeBot
H : Tendsto (⇑UniformFun.ofFun ∘ F) ℱ (𝓝 (UniformFun.ofFun f))
⊢ Tendsto F ℱ (𝓝 f)

case inr.mpr
ι : Type u_1
X : Type u_2
α : Type u_3
inst✝² : TopologicalSpace X
inst✝¹ : UniformSpace α
F : ι → X → α
inst✝ : CompactSpace X
F_eqcont : Equicontinuous F
ℱ : Filter ι
f : X → α
ℱ_ne : ℱ.NeBot
H : Tendsto F ℱ (𝓝 f)
⊢ Tendsto (⇑UniformFun.ofFun ∘ F) ℱ (𝓝 (UniformFun.ofFun f))

Proof state:
case inr.mpr
ι : Type u_1
X : Type u_2
α : Type u_3
inst✝² : TopologicalSpace X
inst✝¹ : UniformSpace α
F : ι → X → α
inst✝ : CompactSpace X
F_eqcont : Equicontinuous F
ℱ : Filter ι
f : X → α
ℱ_ne : ℱ.NeBot
H : Tendsto F ℱ (𝓝 f)
S : Set (X → α) := closure (range F)
𝒢 : Filter ↑S := comap Subtype.val (map F ℱ)
hS : S.Equicontinuous
ind : IsInducing (⇑UniformFun.ofFun ∘ Subtype.val)
f_mem : f ∈ S
h𝒢ℱ : map Subtype.val 𝒢 = map F ℱ
H' : Tendsto id 𝒢 (𝓝 ⟨f, f_mem⟩)
⊢ Tendsto (⇑UniformFun.ofFun ∘ F) ℱ (𝓝 (UniformFun.ofFun f))

Tactic:
rwa [ind.tendsto_nhds_iff, comp_id, ← tendsto_map'_iff, h𝒢ℱ] at H'

Result:
no goals

Proof state:
ι : Type u_1
X : Type u_2
α : Type u_3
inst✝² : TopologicalSpace X
inst✝¹ : UniformSpace α
F : ι → X → α
inst✝ : CompactSpace X
F_eqcont : Equicontinuous F
ℱ : Filter ι
f : X → α
⊢ Tendsto (⇑UniformFun.ofFun ∘ F) ℱ (𝓝 (UniformFun.ofFun f)) ↔ Tendsto F ℱ (𝓝 f)

Tactic:
rcases ℱ.eq_or_neBot with rfl | ℱ_ne

Result:
case inl
ι : Type u_1
X : Type u_2
α : Type u_3
inst✝² : TopologicalSpace X
inst✝¹ : UniformSpace α
F : ι → X → α
inst✝ : CompactSpace X
F_eqcont : Equicontinuous F
f : X → α
⊢ Tendsto (⇑UniformFun.ofFun ∘ F) ⊥ (𝓝 (UniformFun.ofFun f)) ↔ Tendsto F ⊥ (𝓝 f)

case inr
ι : Type u_1
X : Type u_2
α : Type u_3
inst✝² : TopologicalSpace X
inst✝¹ : UniformSpace α
F : ι → X → α
inst✝ : CompactSpace X
F_eqcont : Equicontinuous F
ℱ : Filter ι
f : X → α
ℱ_ne : ℱ.NeBot
⊢ Tendsto (⇑UniformFun.ofFun ∘ F) ℱ (𝓝 (UniformFun.ofFun f)) ↔ Tendsto F ℱ (𝓝 f)

Proof state:
case inr.mpr
ι : Type u_1
X : Type u_2
α : Type u_3
inst✝² : TopologicalSpace X
inst✝¹ : UniformSpace α
F : ι → X → α
inst✝ : CompactSpace X
F_eqcont : Equicontinuous F
ℱ : Filter ι
f : X → α
ℱ_ne : ℱ.NeBot
H : Tendsto F ℱ (𝓝 f)
S : Set (X → α) := closure (range F)
𝒢 : Filter ↑S := comap Subtype.val (map F ℱ)
hS : S.Equicontinuous
ind : IsInducing (⇑UniformFun.ofFun ∘ Subtype.val)
f_mem : f ∈ S
h𝒢ℱ : map Subtype.val 𝒢 = map F ℱ
⊢ Tendsto (⇑UniformFun.ofFun ∘ F) ℱ (𝓝 (UniformFun.ofFun f))

Tactic:
have H' : Tendsto id 𝒢 (𝓝 ⟨f, f_mem⟩) := by
  rwa [tendsto_id', nhds_induced, ← map_le_iff_le_comap, h𝒢ℱ]

Result:
case inr.mpr
ι : Type u_1
X : Type u_2
α : Type u_3
inst✝² : TopologicalSpace X
inst✝¹ : UniformSpace α
F : ι → X → α
inst✝ : CompactSpace X
F_eqcont : Equicontinuous F
ℱ : Filter ι
f : X → α
ℱ_ne : ℱ.NeBot
H : Tendsto F ℱ (𝓝 f)
S : Set (X → α) := closure (range F)
𝒢 : Filter ↑S := comap Subtype.val (map F ℱ)
hS : S.Equicontinuous
ind : IsInducing (⇑UniformFun.ofFun ∘ Subtype.val)
f_mem : f ∈ S
h𝒢ℱ : map Subtype.val 𝒢 = map F ℱ
H' : Tendsto id 𝒢 (𝓝 ⟨f, f_mem⟩)
⊢ Tendsto (⇑UniformFun.ofFun ∘ F) ℱ (𝓝 (UniformFun.ofFun f))

Proof state:
case inr.mp
ι : Type u_1
X : Type u_2
α : Type u_3
inst✝² : TopologicalSpace X
inst✝¹ : UniformSpace α
F : ι → X → α
inst✝ : CompactSpace X
F_eqcont : Equicontinuous F
ℱ : Filter ι
f : X → α
ℱ_ne : ℱ.NeBot
H : Tendsto (⇑UniformFun.ofFun ∘ F) ℱ (𝓝 (UniformFun.ofFun f))
⊢ Tendsto F ℱ (𝓝 f)

Tactic:
exact UniformFun.uniformContinuous_toFun.continuous.tendsto _|>.comp H

Result:
no goals

Proof state:
ι : Type u_1
X : Type u_2
α : Type u_3
inst✝² : TopologicalSpace X
inst✝¹ : UniformSpace α
F : ι → X → α
inst✝ : CompactSpace X
F_eqcont : Equicontinuous F
ℱ : Filter ι
f : X → α
ℱ_ne : ℱ.NeBot
H : Tendsto F ℱ (𝓝 f)
S : Set (X → α) := closure (range F)
𝒢 : Filter ↑S := comap Subtype.val (map F ℱ)
hS : S.Equicontinuous
ind : IsInducing (⇑UniformFun.ofFun ∘ Subtype.val)
f_mem : f ∈ S
h𝒢ℱ : map Subtype.val 𝒢 = map F ℱ
⊢ Tendsto id 𝒢 (𝓝 ⟨f, f_mem⟩)

Tactic:
rwa [tendsto_id', nhds_induced, ← map_le_iff_le_comap, h𝒢ℱ]

Result:
no goals