l3lab/ntp-mathlib huggingface dataset:
/-- A uniformly Cauchy sequence converges uniformly to its limit -/
theorem UniformCauchySeqOnFilter.tendstoUniformlyOnFilter_of_tendsto [NeBot p]
    (hF : UniformCauchySeqOnFilter F p p')
    (hF' : ∀ᶠ x : α in p', Tendsto (fun n => F n x) p (𝓝 (f x))) :
    TendstoUniformlyOnFilter F f p p' := by
  -- Proof idea: |f_n(x) - f(x)| ≤ |f_n(x) - f_m(x)| + |f_m(x) - f(x)|. We choose `n`
  -- so that |f_n(x) - f_m(x)| is uniformly small across `s` whenever `m ≥ n`. Then for
  -- a fixed `x`, we choose `m` sufficiently large such that |f_m(x) - f(x)| is small.
  intro u hu
  rcases comp_symm_of_uniformity hu with ⟨t, ht, htsymm, htmem⟩
  -- We will choose n, x, and m simultaneously. n and x come from hF. m comes from hF'
  -- But we need to promote hF' to the full product filter to use it
  have hmc : ∀ᶠ x in (p ×ˢ p) ×ˢ p', Tendsto (fun n : ι => F n x.snd) p (𝓝 (f x.snd)) := by
    rw [eventually_prod_iff]
    refine' ⟨fun _ => True, by simp, _, hF', by simp⟩
  -- To apply filter operations we'll need to do some order manipulation
  rw [Filter.eventually_swap_iff]
  have := tendsto_prodAssoc.eventually (tendsto_prod_swap.eventually ((hF t ht).and hmc))
  apply this.curry.mono
  

Proof state:
case intro.intro.intro
α : Type u
β : Type v
γ : Type w
ι : Type x
inst✝¹ : UniformSpace β
F : ι → α → β
f : α → β
s s' : Set α
x : α
p : Filter ι
p' : Filter α
g : ι → α
inst✝ : NeBot p
hF : UniformCauchySeqOnFilter F p p'
hF' : ∀ᶠ (x : α) in p', Tendsto (fun n => F n x) p (𝓝 (f x))
u : Set (β × β)
hu : u ∈ 𝓤 β
t : Set (β × β)
ht : t ∈ 𝓤 β
htsymm : ∀ {a b : β}, (a, b) ∈ t → (b, a) ∈ t
htmem : t ○ t ⊆ u
hmc : ∀ᶠ (x : (ι × ι) × α) in (p ×ˢ p) ×ˢ p', Tendsto (fun n => F n x.2) p (𝓝 (f x.2))
this :
  ∀ᶠ (x : (α × ι) × ι) in (p' ×ˢ p) ×ˢ p,
    (F (Prod.swap ((Equiv.prodAssoc α ι ι) x)).1.1 (Prod.swap ((Equiv.prodAssoc α ι ι) x)).2,
          F (Prod.swap ((Equiv.prodAssoc α ι ι) x)).1.2 (Prod.swap ((Equiv.prodAssoc α ι ι) x)).2) ∈
        t ∧
      Tendsto (fun n => F n (Prod.swap ((Equiv.prodAssoc α ι ι) x)).2) p
        (𝓝 (f (Prod.swap ((Equiv.prodAssoc α ι ι) x)).2))
⊢ ∀ (x : α × ι),
    (∀ᶠ (y : ι) in p,
        (F (Prod.swap ((Equiv.prodAssoc α ι ι) (x, y))).1.1 (Prod.swap ((Equiv.prodAssoc α ι ι) (x, y))).2,
              F (Prod.swap ((Equiv.prodAssoc α ι ι) (x, y))).1.2 (Prod.swap ((Equiv.prodAssoc α ι ι) (x, y))).2) ∈
            t ∧
          Tendsto (fun n => F n (Prod.swap ((Equiv.prodAssoc α ι ι) (x, y))).2) p
            (𝓝 (f (Prod.swap ((Equiv.prodAssoc α ι ι) (x, y))).2))) →
      (f (Prod.swap x).2, F (Prod.swap x).1 (Prod.swap x).2) ∈ u

Next tactic:
simp only [Equiv.prodAssoc_apply, eventually_and, eventually_const, Prod.snd_swap, Prod.fst_swap,
    and_imp, Prod.forall]
/-- A uniformly Cauchy sequence converges uniformly to its limit -/
theorem UniformCauchySeqOnFilter.tendstoUniformlyOnFilter_of_tendsto [NeBot p]
    (hF : UniformCauchySeqOnFilter F p p')
    (hF' : ∀ᶠ x : α in p', Tendsto (fun n => F n x) p (𝓝 (f x))) :
    TendstoUniformlyOnFilter F f p p' := by
  -- Proof idea: |f_n(x) - f(x)| ≤ |f_n(x) - f_m(x)| + |f_m(x) - f(x)|. We choose `n`
  -- so that |f_n(x) - f_m(x)| is uniformly small across `s` whenever `m ≥ n`. Then for
  -- a fixed `x`, we choose `m` sufficiently large such that |f_m(x) - f(x)| is small.
  intro u hu
  rcases comp_symm_of_uniformity hu with ⟨t, ht, htsymm, htmem⟩
  -- We will choose n, x, and m simultaneously. n and x come from hF. m comes from hF'
  -- But we need to promote hF' to the full product filter to use it
  have hmc : ∀ᶠ x in (p ×ˢ p) ×ˢ p', Tendsto (fun n : ι => F n x.snd) p (𝓝 (f x.snd)) := by
    rw [eventually_prod_iff]
    refine' ⟨fun _ => True, by simp, _, hF', by simp⟩
  -- To apply filter operations we'll need to do some order manipulation
  rw [Filter.eventually_swap_iff]
  have := tendsto_prodAssoc.eventually (tendsto_prod_swap.eventually ((hF t ht).and hmc))
  apply this.curry.mono
  simp only [Equiv.prodAssoc_apply, eventually_and, eventually_const, Prod.snd_swap, Prod.fst_swap,
    and_imp, Prod.forall]
  -- Complete the proof
  

Proof state:
case intro.intro.intro
α : Type u
β : Type v
γ : Type w
ι : Type x
inst✝¹ : UniformSpace β
F : ι → α → β
f : α → β
s s' : Set α
x : α
p : Filter ι
p' : Filter α
g : ι → α
inst✝ : NeBot p
hF : UniformCauchySeqOnFilter F p p'
hF' : ∀ᶠ (x : α) in p', Tendsto (fun n => F n x) p (𝓝 (f x))
u : Set (β × β)
hu : u ∈ 𝓤 β
t : Set (β × β)
ht : t ∈ 𝓤 β
htsymm : ∀ {a b : β}, (a, b) ∈ t → (b, a) ∈ t
htmem : t ○ t ⊆ u
hmc : ∀ᶠ (x : (ι × ι) × α) in (p ×ˢ p) ×ˢ p', Tendsto (fun n => F n x.2) p (𝓝 (f x.2))
this :
  ∀ᶠ (x : (α × ι) × ι) in (p' ×ˢ p) ×ˢ p,
    (F (Prod.swap ((Equiv.prodAssoc α ι ι) x)).1.1 (Prod.swap ((Equiv.prodAssoc α ι ι) x)).2,
          F (Prod.swap ((Equiv.prodAssoc α ι ι) x)).1.2 (Prod.swap ((Equiv.prodAssoc α ι ι) x)).2) ∈
        t ∧
      Tendsto (fun n => F n (Prod.swap ((Equiv.prodAssoc α ι ι) x)).2) p
        (𝓝 (f (Prod.swap ((Equiv.prodAssoc α ι ι) x)).2))
⊢ ∀ (a : α) (b : ι), (∀ᶠ (x : ι) in p, (F b a, F x a) ∈ t) → Tendsto (fun n => F n a) p (𝓝 (f a)) → (f a, F b a) ∈ u

Next tactic:
intro x n hx hm'
/-- A uniformly Cauchy sequence converges uniformly to its limit -/
theorem UniformCauchySeqOnFilter.tendstoUniformlyOnFilter_of_tendsto [NeBot p]
    (hF : UniformCauchySeqOnFilter F p p')
    (hF' : ∀ᶠ x : α in p', Tendsto (fun n => F n x) p (𝓝 (f x))) :
    TendstoUniformlyOnFilter F f p p' := by
  -- Proof idea: |f_n(x) - f(x)| ≤ |f_n(x) - f_m(x)| + |f_m(x) - f(x)|. We choose `n`
  -- so that |f_n(x) - f_m(x)| is uniformly small across `s` whenever `m ≥ n`. Then for
  -- a fixed `x`, we choose `m` sufficiently large such that |f_m(x) - f(x)| is small.
  intro u hu
  rcases comp_symm_of_uniformity hu with ⟨t, ht, htsymm, htmem⟩
  -- We will choose n, x, and m simultaneously. n and x come from hF. m comes from hF'
  -- But we need to promote hF' to the full product filter to use it
  have hmc : ∀ᶠ x in (p ×ˢ p) ×ˢ p', Tendsto (fun n : ι => F n x.snd) p (𝓝 (f x.snd)) := by
    rw [eventually_prod_iff]
    refine' ⟨fun _ => True, by simp, _, hF', by simp⟩
  -- To apply filter operations we'll need to do some order manipulation
  rw [Filter.eventually_swap_iff]
  have := tendsto_prodAssoc.eventually (tendsto_prod_swap.eventually ((hF t ht).and hmc))
  apply this.curry.mono
  simp only [Equiv.prodAssoc_apply, eventually_and, eventually_const, Prod.snd_swap, Prod.fst_swap,
    and_imp, Prod.forall]
  -- Complete the proof
  intro x n hx hm'
  

Proof state:
case intro.intro.intro
α : Type u
β : Type v
γ : Type w
ι : Type x
inst✝¹ : UniformSpace β
F : ι → α → β
f : α → β
s s' : Set α
x✝ : α
p : Filter ι
p' : Filter α
g : ι → α
inst✝ : NeBot p
hF : UniformCauchySeqOnFilter F p p'
hF' : ∀ᶠ (x : α) in p', Tendsto (fun n => F n x) p (𝓝 (f x))
u : Set (β × β)
hu : u ∈ 𝓤 β
t : Set (β × β)
ht : t ∈ 𝓤 β
htsymm : ∀ {a b : β}, (a, b) ∈ t → (b, a) ∈ t
htmem : t ○ t ⊆ u
hmc : ∀ᶠ (x : (ι × ι) × α) in (p ×ˢ p) ×ˢ p', Tendsto (fun n => F n x.2) p (𝓝 (f x.2))
this :
  ∀ᶠ (x : (α × ι) × ι) in (p' ×ˢ p) ×ˢ p,
    (F (Prod.swap ((Equiv.prodAssoc α ι ι) x)).1.1 (Prod.swap ((Equiv.prodAssoc α ι ι) x)).2,
          F (Prod.swap ((Equiv.prodAssoc α ι ι) x)).1.2 (Prod.swap ((Equiv.prodAssoc α ι ι) x)).2) ∈
        t ∧
      Tendsto (fun n => F n (Prod.swap ((Equiv.prodAssoc α ι ι) x)).2) p
        (𝓝 (f (Prod.swap ((Equiv.prodAssoc α ι ι) x)).2))
x : α
n : ι
hx : ∀ᶠ (x_1 : ι) in p, (F n x, F x_1 x) ∈ t
hm' : Tendsto (fun n => F n x) p (𝓝 (f x))
⊢ (f x, F n x) ∈ u

Next tactic:
refine' Set.mem_of_mem_of_subset (mem_compRel.mpr _) htmem
/-- A uniformly Cauchy sequence converges uniformly to its limit -/
theorem UniformCauchySeqOnFilter.tendstoUniformlyOnFilter_of_tendsto [NeBot p]
    (hF : UniformCauchySeqOnFilter F p p')
    (hF' : ∀ᶠ x : α in p', Tendsto (fun n => F n x) p (𝓝 (f x))) :
    TendstoUniformlyOnFilter F f p p' := by
  -- Proof idea: |f_n(x) - f(x)| ≤ |f_n(x) - f_m(x)| + |f_m(x) - f(x)|. We choose `n`
  -- so that |f_n(x) - f_m(x)| is uniformly small across `s` whenever `m ≥ n`. Then for
  -- a fixed `x`, we choose `m` sufficiently large such that |f_m(x) - f(x)| is small.
  intro u hu
  rcases comp_symm_of_uniformity hu with ⟨t, ht, htsymm, htmem⟩
  -- We will choose n, x, and m simultaneously. n and x come from hF. m comes from hF'
  -- But we need to promote hF' to the full product filter to use it
  have hmc : ∀ᶠ x in (p ×ˢ p) ×ˢ p', Tendsto (fun n : ι => F n x.snd) p (𝓝 (f x.snd)) := by
    rw [eventually_prod_iff]
    refine' ⟨fun _ => True, by simp, _, hF', by simp⟩
  -- To apply filter operations we'll need to do some order manipulation
  rw [Filter.eventually_swap_iff]
  have := tendsto_prodAssoc.eventually (tendsto_prod_swap.eventually ((hF t ht).and hmc))
  apply this.curry.mono
  simp only [Equiv.prodAssoc_apply, eventually_and, eventually_const, Prod.snd_swap, Prod.fst_swap,
    and_imp, Prod.forall]
  -- Complete the proof
  intro x n hx hm'
  refine' Set.mem_of_mem_of_subset (mem_compRel.mpr _) htmem
  

Proof state:
case intro.intro.intro
α : Type u
β : Type v
γ : Type w
ι : Type x
inst✝¹ : UniformSpace β
F : ι → α → β
f : α → β
s s' : Set α
x✝ : α
p : Filter ι
p' : Filter α
g : ι → α
inst✝ : NeBot p
hF : UniformCauchySeqOnFilter F p p'
hF' : ∀ᶠ (x : α) in p', Tendsto (fun n => F n x) p (𝓝 (f x))
u : Set (β × β)
hu : u ∈ 𝓤 β
t : Set (β × β)
ht : t ∈ 𝓤 β
htsymm : ∀ {a b : β}, (a, b) ∈ t → (b, a) ∈ t
htmem : t ○ t ⊆ u
hmc : ∀ᶠ (x : (ι × ι) × α) in (p ×ˢ p) ×ˢ p', Tendsto (fun n => F n x.2) p (𝓝 (f x.2))
this :
  ∀ᶠ (x : (α × ι) × ι) in (p' ×ˢ p) ×ˢ p,
    (F (Prod.swap ((Equiv.prodAssoc α ι ι) x)).1.1 (Prod.swap ((Equiv.prodAssoc α ι ι) x)).2,
          F (Prod.swap ((Equiv.prodAssoc α ι ι) x)).1.2 (Prod.swap ((Equiv.prodAssoc α ι ι) x)).2) ∈
        t ∧
      Tendsto (fun n => F n (Prod.swap ((Equiv.prodAssoc α ι ι) x)).2) p
        (𝓝 (f (Prod.swap ((Equiv.prodAssoc α ι ι) x)).2))
x : α
n : ι
hx : ∀ᶠ (x_1 : ι) in p, (F n x, F x_1 x) ∈ t
hm' : Tendsto (fun n => F n x) p (𝓝 (f x))
⊢ ∃ z, (f x, z) ∈ t ∧ (z, F n x) ∈ t

Next tactic:
rw [Uniform.tendsto_nhds_right] at hm'
/-- A uniformly Cauchy sequence converges uniformly to its limit -/
theorem UniformCauchySeqOnFilter.tendstoUniformlyOnFilter_of_tendsto [NeBot p]
    (hF : UniformCauchySeqOnFilter F p p')
    (hF' : ∀ᶠ x : α in p', Tendsto (fun n => F n x) p (𝓝 (f x))) :
    TendstoUniformlyOnFilter F f p p' := by
  -- Proof idea: |f_n(x) - f(x)| ≤ |f_n(x) - f_m(x)| + |f_m(x) - f(x)|. We choose `n`
  -- so that |f_n(x) - f_m(x)| is uniformly small across `s` whenever `m ≥ n`. Then for
  -- a fixed `x`, we choose `m` sufficiently large such that |f_m(x) - f(x)| is small.
  intro u hu
  rcases comp_symm_of_uniformity hu with ⟨t, ht, htsymm, htmem⟩
  -- We will choose n, x, and m simultaneously. n and x come from hF. m comes from hF'
  -- But we need to promote hF' to the full product filter to use it
  have hmc : ∀ᶠ x in (p ×ˢ p) ×ˢ p', Tendsto (fun n : ι => F n x.snd) p (𝓝 (f x.snd)) := by
    rw [eventually_prod_iff]
    refine' ⟨fun _ => True, by simp, _, hF', by simp⟩
  -- To apply filter operations we'll need to do some order manipulation
  rw [Filter.eventually_swap_iff]
  have := tendsto_prodAssoc.eventually (tendsto_prod_swap.eventually ((hF t ht).and hmc))
  apply this.curry.mono
  simp only [Equiv.prodAssoc_apply, eventually_and, eventually_const, Prod.snd_swap, Prod.fst_swap,
    and_imp, Prod.forall]
  -- Complete the proof
  intro x n hx hm'
  refine' Set.mem_of_mem_of_subset (mem_compRel.mpr _) htmem
  rw [Uniform.tendsto_nhds_right] at hm'
  

Proof state:
case intro.intro.intro
α : Type u
β : Type v
γ : Type w
ι : Type x
inst✝¹ : UniformSpace β
F : ι → α → β
f : α → β
s s' : Set α
x✝ : α
p : Filter ι
p' : Filter α
g : ι → α
inst✝ : NeBot p
hF : UniformCauchySeqOnFilter F p p'
hF' : ∀ᶠ (x : α) in p', Tendsto (fun n => F n x) p (𝓝 (f x))
u : Set (β × β)
hu : u ∈ 𝓤 β
t : Set (β × β)
ht : t ∈ 𝓤 β
htsymm : ∀ {a b : β}, (a, b) ∈ t → (b, a) ∈ t
htmem : t ○ t ⊆ u
hmc : ∀ᶠ (x : (ι × ι) × α) in (p ×ˢ p) ×ˢ p', Tendsto (fun n => F n x.2) p (𝓝 (f x.2))
this :
  ∀ᶠ (x : (α × ι) × ι) in (p' ×ˢ p) ×ˢ p,
    (F (Prod.swap ((Equiv.prodAssoc α ι ι) x)).1.1 (Prod.swap ((Equiv.prodAssoc α ι ι) x)).2,
          F (Prod.swap ((Equiv.prodAssoc α ι ι) x)).1.2 (Prod.swap ((Equiv.prodAssoc α ι ι) x)).2) ∈
        t ∧
      Tendsto (fun n => F n (Prod.swap ((Equiv.prodAssoc α ι ι) x)).2) p
        (𝓝 (f (Prod.swap ((Equiv.prodAssoc α ι ι) x)).2))
x : α
n : ι
hx : ∀ᶠ (x_1 : ι) in p, (F n x, F x_1 x) ∈ t
hm' : Tendsto (fun x_1 => (f x, F x_1 x)) p (𝓤 β)
⊢ ∃ z, (f x, z) ∈ t ∧ (z, F n x) ∈ t

Next tactic:
have := hx.and (hm' ht)
/-- A uniformly Cauchy sequence converges uniformly to its limit -/
theorem UniformCauchySeqOnFilter.tendstoUniformlyOnFilter_of_tendsto [NeBot p]
    (hF : UniformCauchySeqOnFilter F p p')
    (hF' : ∀ᶠ x : α in p', Tendsto (fun n => F n x) p (𝓝 (f x))) :
    TendstoUniformlyOnFilter F f p p' := by
  -- Proof idea: |f_n(x) - f(x)| ≤ |f_n(x) - f_m(x)| + |f_m(x) - f(x)|. We choose `n`
  -- so that |f_n(x) - f_m(x)| is uniformly small across `s` whenever `m ≥ n`. Then for
  -- a fixed `x`, we choose `m` sufficiently large such that |f_m(x) - f(x)| is small.
  intro u hu
  rcases comp_symm_of_uniformity hu with ⟨t, ht, htsymm, htmem⟩
  -- We will choose n, x, and m simultaneously. n and x come from hF. m comes from hF'
  -- But we need to promote hF' to the full product filter to use it
  have hmc : ∀ᶠ x in (p ×ˢ p) ×ˢ p', Tendsto (fun n : ι => F n x.snd) p (𝓝 (f x.snd)) := by
    rw [eventually_prod_iff]
    refine' ⟨fun _ => True, by simp, _, hF', by simp⟩
  -- To apply filter operations we'll need to do some order manipulation
  rw [Filter.eventually_swap_iff]
  have := tendsto_prodAssoc.eventually (tendsto_prod_swap.eventually ((hF t ht).and hmc))
  apply this.curry.mono
  simp only [Equiv.prodAssoc_apply, eventually_and, eventually_const, Prod.snd_swap, Prod.fst_swap,
    and_imp, Prod.forall]
  -- Complete the proof
  intro x n hx hm'
  refine' Set.mem_of_mem_of_subset (mem_compRel.mpr _) htmem
  rw [Uniform.tendsto_nhds_right] at hm'
  have := hx.and (hm' ht)
  

Proof state:
case intro.intro.intro
α : Type u
β : Type v
γ : Type w
ι : Type x
inst✝¹ : UniformSpace β
F : ι → α → β
f : α → β
s s' : Set α
x✝ : α
p : Filter ι
p' : Filter α
g : ι → α
inst✝ : NeBot p
hF : UniformCauchySeqOnFilter F p p'
hF' : ∀ᶠ (x : α) in p', Tendsto (fun n => F n x) p (𝓝 (f x))
u : Set (β × β)
hu : u ∈ 𝓤 β
t : Set (β × β)
ht : t ∈ 𝓤 β
htsymm : ∀ {a b : β}, (a, b) ∈ t → (b, a) ∈ t
htmem : t ○ t ⊆ u
hmc : ∀ᶠ (x : (ι × ι) × α) in (p ×ˢ p) ×ˢ p', Tendsto (fun n => F n x.2) p (𝓝 (f x.2))
this✝ :
  ∀ᶠ (x : (α × ι) × ι) in (p' ×ˢ p) ×ˢ p,
    (F (Prod.swap ((Equiv.prodAssoc α ι ι) x)).1.1 (Prod.swap ((Equiv.prodAssoc α ι ι) x)).2,
          F (Prod.swap ((Equiv.prodAssoc α ι ι) x)).1.2 (Prod.swap ((Equiv.prodAssoc α ι ι) x)).2) ∈
        t ∧
      Tendsto (fun n => F n (Prod.swap ((Equiv.prodAssoc α ι ι) x)).2) p
        (𝓝 (f (Prod.swap ((Equiv.prodAssoc α ι ι) x)).2))
x : α
n : ι
hx : ∀ᶠ (x_1 : ι) in p, (F n x, F x_1 x) ∈ t
hm' : Tendsto (fun x_1 => (f x, F x_1 x)) p (𝓤 β)
this : ∀ᶠ (x_1 : ι) in p, (F n x, F x_1 x) ∈ t ∧ (fun x_2 => (f x, F x_2 x)) x_1 ∈ t
⊢ ∃ z, (f x, z) ∈ t ∧ (z, F n x) ∈ t

Next tactic:
obtain ⟨m, hm⟩ := this.exists
/-- A uniformly Cauchy sequence converges uniformly to its limit -/
theorem UniformCauchySeqOnFilter.tendstoUniformlyOnFilter_of_tendsto [NeBot p]
    (hF : UniformCauchySeqOnFilter F p p')
    (hF' : ∀ᶠ x : α in p', Tendsto (fun n => F n x) p (𝓝 (f x))) :
    TendstoUniformlyOnFilter F f p p' := by
  -- Proof idea: |f_n(x) - f(x)| ≤ |f_n(x) - f_m(x)| + |f_m(x) - f(x)|. We choose `n`
  -- so that |f_n(x) - f_m(x)| is uniformly small across `s` whenever `m ≥ n`. Then for
  -- a fixed `x`, we choose `m` sufficiently large such that |f_m(x) - f(x)| is small.
  intro u hu
  rcases comp_symm_of_uniformity hu with ⟨t, ht, htsymm, htmem⟩
  -- We will choose n, x, and m simultaneously. n and x come from hF. m comes from hF'
  -- But we need to promote hF' to the full product filter to use it
  have hmc : ∀ᶠ x in (p ×ˢ p) ×ˢ p', Tendsto (fun n : ι => F n x.snd) p (𝓝 (f x.snd)) := by
    rw [eventually_prod_iff]
    refine' ⟨fun _ => True, by simp, _, hF', by simp⟩
  -- To apply filter operations we'll need to do some order manipulation
  rw [Filter.eventually_swap_iff]
  have := tendsto_prodAssoc.eventually (tendsto_prod_swap.eventually ((hF t ht).and hmc))
  apply this.curry.mono
  simp only [Equiv.prodAssoc_apply, eventually_and, eventually_const, Prod.snd_swap, Prod.fst_swap,
    and_imp, Prod.forall]
  -- Complete the proof
  intro x n hx hm'
  refine' Set.mem_of_mem_of_subset (mem_compRel.mpr _) htmem
  rw [Uniform.tendsto_nhds_right] at hm'
  have := hx.and (hm' ht)
  obtain ⟨m, hm⟩ := this.exists
  

Proof state:
case intro.intro.intro.intro
α : Type u
β : Type v
γ : Type w
ι : Type x
inst✝¹ : UniformSpace β
F : ι → α → β
f : α → β
s s' : Set α
x✝ : α
p : Filter ι
p' : Filter α
g : ι → α
inst✝ : NeBot p
hF : UniformCauchySeqOnFilter F p p'
hF' : ∀ᶠ (x : α) in p', Tendsto (fun n => F n x) p (𝓝 (f x))
u : Set (β × β)
hu : u ∈ 𝓤 β
t : Set (β × β)
ht : t ∈ 𝓤 β
htsymm : ∀ {a b : β}, (a, b) ∈ t → (b, a) ∈ t
htmem : t ○ t ⊆ u
hmc : ∀ᶠ (x : (ι × ι) × α) in (p ×ˢ p) ×ˢ p', Tendsto (fun n => F n x.2) p (𝓝 (f x.2))
this✝ :
  ∀ᶠ (x : (α × ι) × ι) in (p' ×ˢ p) ×ˢ p,
    (F (Prod.swap ((Equiv.prodAssoc α ι ι) x)).1.1 (Prod.swap ((Equiv.prodAssoc α ι ι) x)).2,
          F (Prod.swap ((Equiv.prodAssoc α ι ι) x)).1.2 (Prod.swap ((Equiv.prodAssoc α ι ι) x)).2) ∈
        t ∧
      Tendsto (fun n => F n (Prod.swap ((Equiv.prodAssoc α ι ι) x)).2) p
        (𝓝 (f (Prod.swap ((Equiv.prodAssoc α ι ι) x)).2))
x : α
n : ι
hx : ∀ᶠ (x_1 : ι) in p, (F n x, F x_1 x) ∈ t
hm' : Tendsto (fun x_1 => (f x, F x_1 x)) p (𝓤 β)
this : ∀ᶠ (x_1 : ι) in p, (F n x, F x_1 x) ∈ t ∧ (fun x_2 => (f x, F x_2 x)) x_1 ∈ t
m : ι
hm : (F n x, F m x) ∈ t ∧ (fun x_1 => (f x, F x_1 x)) m ∈ t
⊢ ∃ z, (f x, z) ∈ t ∧ (z, F n x) ∈ t

Next tactic:
exact ⟨F m x, ⟨hm.2, htsymm hm.1⟩⟩
theorem UniformCauchySeqOnFilter.mono_left {p'' : Filter ι} (hf : UniformCauchySeqOnFilter F p p')
    (hp : p'' ≤ p) : UniformCauchySeqOnFilter F p'' p' := by
  

Proof state:
α : Type u
β : Type v
γ : Type w
ι : Type x
inst✝ : UniformSpace β
F : ι → α → β
f : α → β
s s' : Set α
x : α
p : Filter ι
p' : Filter α
g : ι → α
p'' : Filter ι
hf : UniformCauchySeqOnFilter F p p'
hp : p'' ≤ p
⊢ UniformCauchySeqOnFilter F p'' p'

Next tactic:
intro u hu
theorem UniformCauchySeqOnFilter.mono_left {p'' : Filter ι} (hf : UniformCauchySeqOnFilter F p p')
    (hp : p'' ≤ p) : UniformCauchySeqOnFilter F p'' p' := by
  intro u hu
  

Proof state:
α : Type u
β : Type v
γ : Type w
ι : Type x
inst✝ : UniformSpace β
F : ι → α → β
f : α → β
s s' : Set α
x : α
p : Filter ι
p' : Filter α
g : ι → α
p'' : Filter ι
hf : UniformCauchySeqOnFilter F p p'
hp : p'' ≤ p
u : Set (β × β)
hu : u ∈ 𝓤 β
⊢ ∀ᶠ (m : (ι × ι) × α) in (p'' ×ˢ p'') ×ˢ p', (F m.1.1 m.2, F m.1.2 m.2) ∈ u

Next tactic:
have := (hf u hu).filter_mono (p'.prod_mono_left (Filter.prod_mono hp hp))
theorem UniformCauchySeqOnFilter.mono_left {p'' : Filter ι} (hf : UniformCauchySeqOnFilter F p p')
    (hp : p'' ≤ p) : UniformCauchySeqOnFilter F p'' p' := by
  intro u hu
  have := (hf u hu).filter_mono (p'.prod_mono_left (Filter.prod_mono hp hp))
  

Proof state:
α : Type u
β : Type v
γ : Type w
ι : Type x
inst✝ : UniformSpace β
F : ι → α → β
f : α → β
s s' : Set α
x : α
p : Filter ι
p' : Filter α
g : ι → α
p'' : Filter ι
hf : UniformCauchySeqOnFilter F p p'
hp : p'' ≤ p
u : Set (β × β)
hu : u ∈ 𝓤 β
this : ∀ᶠ (x : (ι × ι) × α) in (p'' ×ˢ p'') ×ˢ p', (F x.1.1 x.2, F x.1.2 x.2) ∈ u
⊢ ∀ᶠ (m : (ι × ι) × α) in (p'' ×ˢ p'') ×ˢ p', (F m.1.1 m.2, F m.1.2 m.2) ∈ u

Next tactic:
exact this.mono (by simp)
theorem UniformCauchySeqOnFilter.mono_left {p'' : Filter ι} (hf : UniformCauchySeqOnFilter F p p')
    (hp : p'' ≤ p) : UniformCauchySeqOnFilter F p'' p' := by
  intro u hu
  have := (hf u hu).filter_mono (p'.prod_mono_left (Filter.prod_mono hp hp))
  exact this.mono (by 

Proof state:
α : Type u
β : Type v
γ : Type w
ι : Type x
inst✝ : UniformSpace β
F : ι → α → β
f : α → β
s s' : Set α
x : α
p : Filter ι
p' : Filter α
g : ι → α
p'' : Filter ι
hf : UniformCauchySeqOnFilter F p p'
hp : p'' ≤ p
u : Set (β × β)
hu : u ∈ 𝓤 β
this : ∀ᶠ (x : (ι × ι) × α) in (p'' ×ˢ p'') ×ˢ p', (F x.1.1 x.2, F x.1.2 x.2) ∈ u
⊢ ∀ (x : (ι × ι) × α), (F x.1.1 x.2, F x.1.2 x.2) ∈ u → (F x.1.1 x.2, F x.1.2 x.2) ∈ u

Next tactic:
simp
theorem UniformCauchySeqOnFilter.mono_right {p'' : Filter α} (hf : UniformCauchySeqOnFilter F p p')
    (hp : p'' ≤ p') : UniformCauchySeqOnFilter F p p'' := fun u hu =>
  have := (hf u hu).filter_mono ((p ×ˢ p).prod_mono_right hp)
  this.mono (by 

Proof state:
α : Type u
β : Type v
γ : Type w
ι : Type x
inst✝ : UniformSpace β
F : ι → α → β
f : α → β
s s' : Set α
x : α
p : Filter ι
p' : Filter α
g : ι → α
p'' : Filter α
hf : UniformCauchySeqOnFilter F p p'
hp : p'' ≤ p'
u : Set (β × β)
hu : u ∈ 𝓤 β
this : ∀ᶠ (x : (ι × ι) × α) in (p ×ˢ p) ×ˢ p'', (F x.1.1 x.2, F x.1.2 x.2) ∈ u
⊢ ∀ (x : (ι × ι) × α), (F x.1.1 x.2, F x.1.2 x.2) ∈ u → (F x.1.1 x.2, F x.1.2 x.2) ∈ u

Next tactic:
simp
theorem UniformCauchySeqOn.mono {s' : Set α} (hf : UniformCauchySeqOn F p s) (hss' : s' ⊆ s) :
    UniformCauchySeqOn F p s' := by
  

Proof state:
α : Type u
β : Type v
γ : Type w
ι : Type x
inst✝ : UniformSpace β
F : ι → α → β
f : α → β
s s'✝ : Set α
x : α
p : Filter ι
p' : Filter α
g : ι → α
s' : Set α
hf : UniformCauchySeqOn F p s
hss' : s' ⊆ s
⊢ UniformCauchySeqOn F p s'

Next tactic:
rw [uniformCauchySeqOn_iff_uniformCauchySeqOnFilter] at hf ⊢
theorem UniformCauchySeqOn.mono {s' : Set α} (hf : UniformCauchySeqOn F p s) (hss' : s' ⊆ s) :
    UniformCauchySeqOn F p s' := by
  rw [uniformCauchySeqOn_iff_uniformCauchySeqOnFilter] at hf ⊢
  

Proof state:
α : Type u
β : Type v
γ : Type w
ι : Type x
inst✝ : UniformSpace β
F : ι → α → β
f : α → β
s s'✝ : Set α
x : α
p : Filter ι
p' : Filter α
g : ι → α
s' : Set α
hf : UniformCauchySeqOnFilter F p (𝓟 s)
hss' : s' ⊆ s
⊢ UniformCauchySeqOnFilter F p (𝓟 s')

Next tactic:
exact hf.mono_right (le_principal_iff.mpr <| mem_principal.mpr hss')
/-- Composing on the right by a function preserves uniform Cauchy sequences -/
theorem UniformCauchySeqOnFilter.comp {γ : Type*} (hf : UniformCauchySeqOnFilter F p p')
    (g : γ → α) : UniformCauchySeqOnFilter (fun n => F n ∘ g) p (p'.comap g) := fun u hu => by
  

Proof state:
α : Type u
β : Type v
γ✝ : Type w
ι : Type x
inst✝ : UniformSpace β
F : ι → α → β
f : α → β
s s' : Set α
x : α
p : Filter ι
p' : Filter α
g✝ : ι → α
γ : Type u_1
hf : UniformCauchySeqOnFilter F p p'
g : γ → α
u : Set (β × β)
hu : u ∈ 𝓤 β
⊢ ∀ᶠ (m : (ι × ι) × γ) in (p ×ˢ p) ×ˢ comap g p', ((fun n => F n ∘ g) m.1.1 m.2, (fun n => F n ∘ g) m.1.2 m.2) ∈ u

Next tactic:
obtain ⟨pa, hpa, pb, hpb, hpapb⟩ := eventually_prod_iff.mp (hf u hu)
/-- Composing on the right by a function preserves uniform Cauchy sequences -/
theorem UniformCauchySeqOnFilter.comp {γ : Type*} (hf : UniformCauchySeqOnFilter F p p')
    (g : γ → α) : UniformCauchySeqOnFilter (fun n => F n ∘ g) p (p'.comap g) := fun u hu => by
  obtain ⟨pa, hpa, pb, hpb, hpapb⟩ := eventually_prod_iff.mp (hf u hu)
  

Proof state:
case intro.intro.intro.intro
α : Type u
β : Type v
γ✝ : Type w
ι : Type x
inst✝ : UniformSpace β
F : ι → α → β
f : α → β
s s' : Set α
x : α
p : Filter ι
p' : Filter α
g✝ : ι → α
γ : Type u_1
hf : UniformCauchySeqOnFilter F p p'
g : γ → α
u : Set (β × β)
hu : u ∈ 𝓤 β
pa : ι × ι → Prop
hpa : ∀ᶠ (x : ι × ι) in p ×ˢ p, pa x
pb : α → Prop
hpb : ∀ᶠ (y : α) in p', pb y
hpapb : ∀ {x : ι × ι}, pa x → ∀ {y : α}, pb y → (F (x, y).1.1 (x, y).2, F (x, y).1.2 (x, y).2) ∈ u
⊢ ∀ᶠ (m : (ι × ι) × γ) in (p ×ˢ p) ×ˢ comap g p', ((fun n => F n ∘ g) m.1.1 m.2, (fun n => F n ∘ g) m.1.2 m.2) ∈ u

Next tactic:
rw [eventually_prod_iff]