mathlib-initiative/mathlib-tactics huggingface dataset:
Module: Mathlib.Topology.ContinuousMap.StoneWeierstrass

Goal state before:
pp: X : Type u_1
inst✝¹ : TopologicalSpace X
inst✝ : CompactSpace X
L : Set C(X, ℝ)
nA : L.Nonempty
inf_mem : ∀ f ∈ L, ∀ g ∈ L, f ⊓ g ∈ L
sup_mem : ∀ f ∈ L, ∀ g ∈ L, f ⊔ g ∈ L
sep : ∀ (v : X → ℝ) (x y : X), ∃ f ∈ L, f x = v x ∧ f y = v y
f : C(X, ℝ)
ε : ℝ
pos : 0 < ε
nX : Nonempty X
g : X → X → C(X, ℝ)
hg : ∀ (x y : X), g x y ∈ L
w₁ : ∀ (x y : X), (g x y) x = f x
w₂ : ∀ (x y : X), (g x y) y = f y
U : X → X → Set X := fun x y ↦ {z | f z - ε < (g x y) z}
U_nhds_y : ∀ (x y : X), U x y ∈ 𝓝 y
ys : X → Finset X := fun x ↦ ⋯.choose
ys_w : ∀ (x : X), ⋃ y ∈ ys x, U x y = ⊤ :=
  fun x ↦ Exists.choose_spec (CompactSpace.elim_nhds_subcover (U x) (U_nhds_y x))
ys_nonempty : ∀ (x : X), (ys x).Nonempty
h : X → ↑L := fun x ↦ ⟨(ys x).sup' ⋯ fun y ↦ g x y, ⋯⟩
lt_h : ∀ (x z : X), f z - ε < ↑(h x) z
h_eq : ∀ (x : X), ↑(h x) x = f x
W : X → Set X := fun x ↦ {z | ↑(h x) z < f z + ε}
W_nhds : ∀ (x : X), W x ∈ 𝓝 x
xs : Finset X := ⋯.choose
xs_w : ⋃ x ∈ xs, W x = ⊤ := Exists.choose_spec (CompactSpace.elim_nhds_subcover W W_nhds)
xs_nonempty : xs.Nonempty
k : ↑L := ⟨xs.inf' xs_nonempty fun x ↦ ↑(h x), ⋯⟩
z : X
⊢ ∀ (a b ε : ℝ), dist a b < ε ↔ a < b + ε ∧ b - ε < a

Tactic:
intros

Goal state after:
X : Type u_1
inst✝¹ : TopologicalSpace X
inst✝ : CompactSpace X
L : Set C(X, ℝ)
nA : L.Nonempty
inf_mem : ∀ f ∈ L, ∀ g ∈ L, f ⊓ g ∈ L
sup_mem : ∀ f ∈ L, ∀ g ∈ L, f ⊔ g ∈ L
sep : ∀ (v : X → ℝ) (x y : X), ∃ f ∈ L, f x = v x ∧ f y = v y
f : C(X, ℝ)
ε : ℝ
pos : 0 < ε
nX : Nonempty X
g : X → X → C(X, ℝ)
hg : ∀ (x y : X), g x y ∈ L
w₁ : ∀ (x y : X), (g x y) x = f x
w₂ : ∀ (x y : X), (g x y) y = f y
U : X → X → Set X := fun x y ↦ {z | f z - ε < (g x y) z}
U_nhds_y : ∀ (x y : X), U x y ∈ 𝓝 y
ys : X → Finset X := fun x ↦ ⋯.choose
ys_w : ∀ (x : X), ⋃ y ∈ ys x, U x y = ⊤ :=
  fun x ↦ Exists.choose_spec (CompactSpace.elim_nhds_subcover (U x) (U_nhds_y x))
ys_nonempty : ∀ (x : X), (ys x).Nonempty
h : X → ↑L := fun x ↦ ⟨(ys x).sup' ⋯ fun y ↦ g x y, ⋯⟩
lt_h : ∀ (x z : X), f z - ε < ↑(h x) z
h_eq : ∀ (x : X), ↑(h x) x = f x
W : X → Set X := fun x ↦ {z | ↑(h x) z < f z + ε}
W_nhds : ∀ (x : X), W x ∈ 𝓝 x
xs : Finset X := ⋯.choose
xs_w : ⋃ x ∈ xs, W x = ⊤ := Exists.choose_spec (CompactSpace.elim_nhds_subcover W W_nhds)
xs_nonempty : xs.Nonempty
k : ↑L := ⟨xs.inf' xs_nonempty fun x ↦ ↑(h x), ⋯⟩
z : X
a✝ b✝ ε✝ : ℝ
⊢ dist a✝ b✝ < ε✝ ↔ a✝ < b✝ + ε✝ ∧ b✝ - ε✝ < a✝
Module: Mathlib.Analysis.CStarAlgebra.ContinuousFunctionalCalculus.Unique

Goal state before:
pp: X : Type u_1
inst✝¹ : TopologicalSpace X
inst✝ : Zero X
f g : C(X, ℝ)₀
⊢ ↑((f + g).toNNReal + (-f).toNNReal + (-g).toNNReal) = ↑((-(f + g)).toNNReal + f.toNNReal + g.toNNReal)

Tactic:
simpa only [map_add, map_mul, map_neg, toContinuousMapHom_toNNReal]
    using! (f : C(X, ℝ)).toNNReal_add_add_neg_add_neg_eq g

Goal state after:
Module: Mathlib.Topology.ContinuousMap.StoneWeierstrass

Goal state before:
pp: case star
𝕜 : Type u_1
inst✝ : RCLike 𝕜
s : Set 𝕜
h0 : 0 ∈ s
f✝ f : C(↑s, 𝕜)
hx✝ : f ∈ adjoin 𝕜 {restrict s (ContinuousMap.id 𝕜)}
hf : f ∈ ↑(RingHom.ker (evalStarAlgHom 𝕜 𝕜 ⟨0, h0⟩))
⊢ star f ∈ ↑(RingHom.ker (evalStarAlgHom 𝕜 𝕜 ⟨0, h0⟩))

Tactic:
| star f _ hf =>

Goal state after:
Module: Mathlib.Topology.Sets.VietorisTopology

Goal state before:
pp: α : Type u_1
inst✝ : TopologicalSpace α
F : Set α
h : IsClosed[inst✝] F
⊢ IsClosed[TopologicalSpace.vietoris α] (𝒫 F)

Tactic:
powerset,

Goal state after:
α : Type u_1
inst✝ : TopologicalSpace α
F : Set α
h : IsClosed[inst✝] F
⊢ IsClosed[TopologicalSpace.vietoris α] {t | t ⊆ F}
Module: Mathlib.Topology.Semicontinuity.Hemicontinuity

Goal state before:
pp: α : Type u_3
β : Type u_4
inst✝² : TopologicalSpace α
inst✝¹ : TopologicalSpace β
f : α → Set β
x₀ : α
inst✝ : (𝓝 x₀).IsCountablyGenerated
K : Set β
hK : IsSeqCompact K
hf : ∀ᶠ (x : α) in 𝓝 x₀, f x ⊆ K
h :
  ∀ (x : ℕ → α),
    Tendsto x atTop (𝓝 x₀) → ∀ (y : ℕ → β), (∀ (n : ℕ), y n ∈ f (x n)) → ∀ (y₀ : β), Tendsto y atTop (𝓝 y₀) → y₀ ∈ f x₀
t : Set β
ht : IsClosed[inst✝¹] t
hft : ∃ᶠ (x' : α) in 𝓝 x₀, (f x' ∩ t).Nonempty
x : ℕ → α
hx : Tendsto x atTop (𝓝 x₀)
y : ℕ → β
hy : ∀ (n : ℕ), y n ∈ f (x n) ∩ t
y₀ : β
hy₀ : y₀ ∈ K
φ : ℕ → ℕ
hφ : StrictMono φ
hyφ : Tendsto (y ∘ φ) atTop (𝓝 y₀)
⊢ (f x₀ ∩ t).Nonempty

Tactic:
specialize h (x ∘ φ) (hx.comp hφ.tendsto_atTop) (y ∘ φ) (fun n ↦ (hy _).1) _ hyφ

Goal state after:
α : Type u_3
β : Type u_4
inst✝² : TopologicalSpace α
inst✝¹ : TopologicalSpace β
f : α → Set β
x₀ : α
inst✝ : (𝓝 x₀).IsCountablyGenerated
K : Set β
hK : IsSeqCompact K
hf : ∀ᶠ (x : α) in 𝓝 x₀, f x ⊆ K
t : Set β
ht : IsClosed[inst✝¹] t
hft : ∃ᶠ (x' : α) in 𝓝 x₀, (f x' ∩ t).Nonempty
x : ℕ → α
hx : Tendsto x atTop (𝓝 x₀)
y : ℕ → β
hy : ∀ (n : ℕ), y n ∈ f (x n) ∩ t
y₀ : β
h : y₀ ∈ f x₀
hy₀ : y₀ ∈ K
φ : ℕ → ℕ
hφ : StrictMono φ
hyφ : Tendsto (y ∘ φ) atTop (𝓝 y₀)
⊢ (f x₀ ∩ t).Nonempty
Module: Mathlib.Topology.UniformSpace.Closeds

Goal state before:
pp: case right
α : Type u_1
inst✝ : UniformSpace α
⊢ IsOpen[(UniformSpace.hausdorff α).toTopologicalSpace] {∅}

Tactic:
simp_rw [isOpen_iff_mem_nhds, Set.mem_singleton_iff, forall_eq, nhds_eq_uniformity]

Goal state after:
case right
α : Type u_1
inst✝ : UniformSpace α
⊢ {∅} ∈ (𝓤 (Set α)).lift' (ball ∅)
Module: Mathlib.Topology.Semicontinuity.Hemicontinuity

Goal state before:
pp: α : Type u_1
β : Type u_2
inst✝² : TopologicalSpace α
f : α → Set β
s : Set α
ι : Type u_3
F : ι → α → Set β
l : Filter ι
inst✝¹ : l.NeBot
inst✝ : UniformSpace β
htendsto : TendstoUniformlyOn F f l s
hF : ∀ (n : ι), UpperHemicontinuousOn (F n) s
hf_compact : ∀ x ∈ s, IsCompact (f x)
⊢ UpperHemicontinuousOn f s

Tactic:
upperHemicontinuousOn_iff_forall_isOpen

Goal state after:
α : Type u_1
β : Type u_2
inst✝² : TopologicalSpace α
f : α → Set β
s : Set α
ι : Type u_3
F : ι → α → Set β
l : Filter ι
inst✝¹ : l.NeBot
inst✝ : UniformSpace β
htendsto : TendstoUniformlyOn F f l s
hF : ∀ (n : ι), UpperHemicontinuousOn (F n) s
hf_compact : ∀ x ∈ s, IsCompact (f x)
⊢ ∀ x ∈ s, ∀ (u : Set β), IsOpen[inst✝.toTopologicalSpace] u → f x ⊆ u → ∀ᶠ (x' : α) in 𝓝[s] x, f x' ⊆ u
Module: Mathlib.Topology.Sets.VietorisTopology

Goal state before:
pp: α : Type u_1
β : Type u_2
inst✝¹ : TopologicalSpace α
inst✝ : TopologicalSpace β
f : α → Set β
x✝ :
  (∀ (U : Set β), IsOpen[inst✝] U → IsOpen[inst✝¹] (f ⁻¹' 𝒫 U)) ∧
    ∀ (F : Set β), IsClosed[inst✝] F → IsClosed[inst✝¹] (f ⁻¹' 𝒫 F)
h₁ : ∀ (U : Set β), IsOpen[inst✝] U → IsOpen[inst✝¹] (f ⁻¹' 𝒫 U)
h₂ : ∀ (F : Set β), IsClosed[inst✝] F → IsClosed[inst✝¹] (f ⁻¹' 𝒫 F)
⊢ Continuous[inst✝¹, TopologicalSpace.vietoris β] f

Tactic:
rw [continuous_generateFrom_iff]

Goal state after:
α : Type u_1
β : Type u_2
inst✝¹ : TopologicalSpace α
inst✝ : TopologicalSpace β
f : α → Set β
x✝ :
  (∀ (U : Set β), IsOpen[inst✝] U → IsOpen[inst✝¹] (f ⁻¹' 𝒫 U)) ∧
    ∀ (F : Set β), IsClosed[inst✝] F → IsClosed[inst✝¹] (f ⁻¹' 𝒫 F)
h₁ : ∀ (U : Set β), IsOpen[inst✝] U → IsOpen[inst✝¹] (f ⁻¹' 𝒫 U)
h₂ : ∀ (F : Set β), IsClosed[inst✝] F → IsClosed[inst✝¹] (f ⁻¹' 𝒫 F)
⊢ ∀ s ∈ powerset '' {U | IsOpen[inst✝] U} ∪ (fun V ↦ {s | (s ∩ V).Nonempty}) '' {V | IsOpen[inst✝] V},
    IsOpen[inst✝¹] (f ⁻¹' s)
Module: Mathlib.Topology.Sets.VietorisTopology

Goal state before:
pp: α : Type u_1
inst✝ : TopologicalSpace α
⊢ inst✝ =
    generateFrom
      ((fun x ↦ (fun x ↦ {x}) ⁻¹' 𝒫 x) '' {U | IsOpen[inst✝] U} ∪
        (fun x ↦ (fun x ↦ {x}) ⁻¹' {s | (s ∩ x).Nonempty}) '' {U | IsOpen[inst✝] U})

Tactic:
powerset,

Goal state after:
α : Type u_1
inst✝ : TopologicalSpace α
⊢ inst✝ =
    generateFrom
      ((fun x ↦ (fun x ↦ {x}) ⁻¹' {t | t ⊆ x}) '' {U | IsOpen[inst✝] U} ∪
        (fun x ↦ (fun x ↦ {x}) ⁻¹' {s | (s ∩ x).Nonempty}) '' {U | IsOpen[inst✝] U})
Module: Mathlib.Topology.Sets.VietorisTopology

Goal state before:
pp: α : Type u_1
inst✝ : TopologicalSpace α
⊢ (∀ (U : Set α), IsOpen[inst✝] U → IsOpen[instTopologicalSpaceProd] ((fun x ↦ x.1 ∪ x.2) ⁻¹' 𝒫 U)) ∧
    ∀ (F : Set α), IsClosed[inst✝] F → IsClosed[instTopologicalSpaceProd] ((fun x ↦ x.1 ∪ x.2) ⁻¹' 𝒫 F)

Tactic:
powerset,

Goal state after:
α : Type u_1
inst✝ : TopologicalSpace α
⊢ (∀ (U : Set α), IsOpen[inst✝] U → IsOpen[instTopologicalSpaceProd] ((fun x ↦ x.1 ∪ x.2) ⁻¹' {t | t ⊆ U})) ∧
    ∀ (F : Set α), IsClosed[inst✝] F → IsClosed[instTopologicalSpaceProd] ((fun x ↦ x.1 ∪ x.2) ⁻¹' {t | t ⊆ F})
Module: Mathlib.Topology.Sets.VietorisTopology

Goal state before:
pp: α : Type u_1
inst✝¹ : TopologicalSpace α
ι : Type u_4
inst✝ : Finite ι
⊢ (∀ (U : Set α), IsOpen[inst✝¹] U → IsOpen[Pi.topologicalSpace] (range ⁻¹' 𝒫 U)) ∧
    ∀ (F : Set α), IsClosed[inst✝¹] F → IsClosed[Pi.topologicalSpace] (range ⁻¹' 𝒫 F)

Tactic:
powerset,

Goal state after:
α : Type u_1
inst✝¹ : TopologicalSpace α
ι : Type u_4
inst✝ : Finite ι
⊢ (∀ (U : Set α), IsOpen[inst✝¹] U → IsOpen[Pi.topologicalSpace] (range ⁻¹' {t | t ⊆ U})) ∧
    ∀ (F : Set α), IsClosed[inst✝¹] F → IsClosed[Pi.topologicalSpace] (range ⁻¹' {t | t ⊆ F})
Module: Mathlib.Topology.UniformSpace.Closeds

Goal state before:
pp: α : Type u_1
β : Type u_2
γ : Type u_3
inst✝³ : UniformSpace α
inst✝² : UniformSpace β
inst✝¹ : UniformSpace γ
inst✝ : CompactSpace α
⊢ IsCompact Set.univ

Tactic:
rw [isCompact_iff_ultrafilter_le_nhds]
    rintro f -
    let := TopologicalSpace.vietoris α
    -- `f.lim` is the limit of `f` in the Vietoris topology
    refine ⟨closure f.lim, Set.mem_univ _, ?_⟩
    grw [isClosed_closure.isCompact.nhds_hausdorff_eq_nhds_vietoris,
      ← TopologicalSpace.vietoris.specializes_closure.nhds_le_nhds, f.le_nhds_lim]

Goal state after:
Module: Mathlib.Topology.Sets.VietorisTopology

Goal state before:
pp: α : Type u_1
β : Type u_2
inst✝¹ : TopologicalSpace α
inst✝ : TopologicalSpace β
f : α → β
hf : Continuous[inst✝¹, inst✝] f
⊢ (∀ (U : Set β), IsOpen[inst✝] U → IsOpen[TopologicalSpace.vietoris α] ((fun x ↦ f '' x) ⁻¹' 𝒫 U)) ∧
    ∀ (F : Set β), IsClosed[inst✝] F → IsClosed[TopologicalSpace.vietoris α] ((fun x ↦ f '' x) ⁻¹' 𝒫 F)

Tactic:
powerset,

Goal state after:
α : Type u_1
β : Type u_2
inst✝¹ : TopologicalSpace α
inst✝ : TopologicalSpace β
f : α → β
hf : Continuous[inst✝¹, inst✝] f
⊢ (∀ (U : Set β), IsOpen[inst✝] U → IsOpen[TopologicalSpace.vietoris α] ((fun x ↦ f '' x) ⁻¹' {t | t ⊆ U})) ∧
    ∀ (F : Set β), IsClosed[inst✝] F → IsClosed[TopologicalSpace.vietoris α] ((fun x ↦ f '' x) ⁻¹' {t | t ⊆ F})
Module: Mathlib.Topology.Sets.VietorisTopology

Goal state before:
pp: α : Type u_1
β : Type u_2
inst✝¹ : TopologicalSpace α
inst✝ : TopologicalSpace β
f : α → β
hf : IsInducing f
this : {U | IsOpen[inst✝¹] U} = (fun x ↦ f ⁻¹' x) '' {V | IsOpen[inst✝] V}
⊢ generateFrom
      ((fun x ↦ 𝒫 (f ⁻¹' x)) '' {V | IsOpen[inst✝] V} ∪
        (fun x ↦ {s | (s ∩ f ⁻¹' x).Nonempty}) '' {V | IsOpen[inst✝] V}) =
    generateFrom
      ((fun x ↦ (fun x ↦ f '' x) ⁻¹' 𝒫 x) '' {V | IsOpen[inst✝] V} ∪
        (fun x ↦ (fun x ↦ f '' x) ⁻¹' {s | (s ∩ x).Nonempty}) '' {V | IsOpen[inst✝] V})

Tactic:
powerset,

Goal state after:
α : Type u_1
β : Type u_2
inst✝¹ : TopologicalSpace α
inst✝ : TopologicalSpace β
f : α → β
hf : IsInducing f
this : {U | IsOpen[inst✝¹] U} = (fun x ↦ f ⁻¹' x) '' {V | IsOpen[inst✝] V}
⊢ generateFrom
      ((fun x ↦ {t | t ⊆ f ⁻¹' x}) '' {V | IsOpen[inst✝] V} ∪
        (fun x ↦ {s | (s ∩ f ⁻¹' x).Nonempty}) '' {V | IsOpen[inst✝] V}) =
    generateFrom
      ((fun x ↦ (fun x ↦ f '' x) ⁻¹' {t | t ⊆ x}) '' {V | IsOpen[inst✝] V} ∪
        (fun x ↦ (fun x ↦ f '' x) ⁻¹' {s | (s ∩ x).Nonempty}) '' {V | IsOpen[inst✝] V})
Module: Mathlib.Analysis.Normed.Algebra.Spectrum

Goal state before:
pp: 𝕜 : Type u_3
A : Type u_4
SA : Type u_5
inst✝⁵ : NormedRing A
inst✝⁴ : CompleteSpace A
inst✝³ : SetLike SA A
inst✝² : SubringClass SA A
inst✝¹ : NormedField 𝕜
inst✝ : NormedAlgebra 𝕜 A
instSMulMem : SMulMemClass SA 𝕜 A
S : SA
hS : IsClosed[PseudoMetricSpace.toUniformSpace.toTopologicalSpace] ↑S
x : ↥S
this : CompleteSpace ↥S
μ : 𝕜
h : IsUnit ((algebraMap 𝕜 A) μ - ↑x)
hμ₁ : ClusterPt μ (𝓟 (σ 𝕜 x)ᶜ)
hμ₂ : μ ∉ (σ 𝕜 x)ᶜ
⊢ map (fun x_1 ↦ (algebraMap 𝕜 ↥S) x_1 - x) (𝓝 μ) ≤ 𝓝 ((algebraMap 𝕜 ↥S) μ - x)

Tactic:
rw [← Filter.Tendsto, ← ContinuousAt]

Goal state after:
𝕜 : Type u_3
A : Type u_4
SA : Type u_5
inst✝⁵ : NormedRing A
inst✝⁴ : CompleteSpace A
inst✝³ : SetLike SA A
inst✝² : SubringClass SA A
inst✝¹ : NormedField 𝕜
inst✝ : NormedAlgebra 𝕜 A
instSMulMem : SMulMemClass SA 𝕜 A
S : SA
hS : IsClosed[PseudoMetricSpace.toUniformSpace.toTopologicalSpace] ↑S
x : ↥S
this : CompleteSpace ↥S
μ : 𝕜
h : IsUnit ((algebraMap 𝕜 A) μ - ↑x)
hμ₁ : ClusterPt μ (𝓟 (σ 𝕜 x)ᶜ)
hμ₂ : μ ∉ (σ 𝕜 x)ᶜ
⊢ ContinuousAt (fun x_1 ↦ (algebraMap 𝕜 ↥S) x_1 - x) μ
Module: Mathlib.Topology.Sets.VietorisTopology

Goal state before:
pp: case neg
α : Type u_1
inst✝ : TopologicalSpace α
s : Set (Set α)
hs : IsPreconnected s
t : Set α
hts : t ∈ s
ht : IsPreconnected t
hts' : t ⊆ ⋃₀ s
U V : Set α
hU : IsOpen[inst✝] U
hV : IsOpen[inst✝] V
hUV : ⋃₀ s ⊆ U ∪ V
ht' : ¬t ⊆ U ∧ ¬t ⊆ V
⊢ (⋃₀ s ∩ U).Nonempty → (⋃₀ s ∩ V).Nonempty → (⋃₀ s ∩ (U ∩ V)).Nonempty

Tactic:
rintro - -

Goal state after:
case neg
α : Type u_1
inst✝ : TopologicalSpace α
s : Set (Set α)
hs : IsPreconnected s
t : Set α
hts : t ∈ s
ht : IsPreconnected t
hts' : t ⊆ ⋃₀ s
U V : Set α
hU : IsOpen[inst✝] U
hV : IsOpen[inst✝] V
hUV : ⋃₀ s ⊆ U ∪ V
ht' : ¬t ⊆ U ∧ ¬t ⊆ V
⊢ (⋃₀ s ∩ (U ∩ V)).Nonempty
Module: Mathlib.Topology.Sets.VietorisTopology

Goal state before:
pp: case inr
α : Type u_1
inst✝ : TopologicalSpace α
B : Set (Set α)
hB : IsTopologicalBasis B
V : Set α
u : Set (Set α)
hV : IsOpen[inst✝] V
hu : u.Finite
huB : u ⊆ B
huV : ∀ U ∈ u, U ⊆ V
K : Compacts α
hKu : ∀ U ∈ u, (↑K ∩ U).Nonempty
w : Set (Set α)
hKV : ↑K ⊆ ⋃₀ w
hwB : w ⊆ B
hwV : ⋃₀ w ⊆ V
hwK : ∀ W ∈ w, (↑K ∩ W).Nonempty
this :
  ∀ (w : Set (Set α)),
    ↑K ⊆ ⋃₀ w →
      w ⊆ B →
        ⋃₀ w ⊆ V →
          (∀ W ∈ w, (↑K ∩ W).Nonempty) →
            w.Finite →
              ∃ v ∈ (fun u ↦ {K | ↑K ⊆ ⋃₀ u ∧ ∀ U ∈ u, (↑K ∩ U).Nonempty}) '' {u | u.Finite ∧ u ⊆ B},
                K ∈ v ∧ v ⊆ SetLike.coe ⁻¹' {s | s ⊆ V ∧ ∀ U ∈ u, (s ∩ U).Nonempty}
hw : ¬w.Finite
⊢ ∃ v ∈ (fun u ↦ {K | ↑K ⊆ ⋃₀ u ∧ ∀ U ∈ u, (↑K ∩ U).Nonempty}) '' {u | u.Finite ∧ u ⊆ B},
    K ∈ v ∧ v ⊆ SetLike.coe ⁻¹' {s | s ⊆ V ∧ ∀ U ∈ u, (s ∩ U).Nonempty}

pp: α : Type u_1
inst✝ : TopologicalSpace α
B : Set (Set α)
hB : IsTopologicalBasis B
V : Set α
u : Set (Set α)
hV : IsOpen[inst✝] V
hu : u.Finite
huB : u ⊆ B
huV : ∀ U ∈ u, U ⊆ V
K : Compacts α
hKu : ∀ U ∈ u, (↑K ∩ U).Nonempty
w : Set (Set α)
hKV : ↑K ⊆ ⋃₀ w
hwB : w ⊆ B
hwV : ⋃₀ w ⊆ V
hwK : ∀ W ∈ w, (↑K ∩ W).Nonempty
hw : w.Finite
⊢ ∃ v ∈ (fun u ↦ {K | ↑K ⊆ ⋃₀ u ∧ ∀ U ∈ u, (↑K ∩ U).Nonempty}) '' {u | u.Finite ∧ u ⊆ B},
    K ∈ v ∧ v ⊆ SetLike.coe ⁻¹' {s | s ⊆ V ∧ ∀ U ∈ u, (s ∩ U).Nonempty}

Tactic:
· rw [sUnion_eq_biUnion] at hKV
      obtain ⟨w', _⟩ := K.isCompact.elim_finite_subcover_image (fun W hW => hB.isOpen (hwB hW)) hKV
      apply this w' <;> grind [sUnion_eq_biUnion]

Goal state after:
α : Type u_1
inst✝ : TopologicalSpace α
B : Set (Set α)
hB : IsTopologicalBasis B
V : Set α
u : Set (Set α)
hV : IsOpen[inst✝] V
hu : u.Finite
huB : u ⊆ B
huV : ∀ U ∈ u, U ⊆ V
K : Compacts α
hKu : ∀ U ∈ u, (↑K ∩ U).Nonempty
w : Set (Set α)
hKV : ↑K ⊆ ⋃₀ w
hwB : w ⊆ B
hwV : ⋃₀ w ⊆ V
hwK : ∀ W ∈ w, (↑K ∩ W).Nonempty
hw : w.Finite
⊢ ∃ v ∈ (fun u ↦ {K | ↑K ⊆ ⋃₀ u ∧ ∀ U ∈ u, (↑K ∩ U).Nonempty}) '' {u | u.Finite ∧ u ⊆ B},
    K ∈ v ∧ v ⊆ SetLike.coe ⁻¹' {s | s ⊆ V ∧ ∀ U ∈ u, (s ∩ U).Nonempty}
Module: Mathlib.Analysis.CStarAlgebra.ContinuousFunctionalCalculus.Isometric

Goal state before:
pp: A : Type u_1
inst✝⁸ : NonUnitalNormedRing A
inst✝⁷ : StarRing A
inst✝⁶ : NormedSpace ℝ A
inst✝⁵ : IsScalarTower ℝ A A
inst✝⁴ : SMulCommClass ℝ A A
inst✝³ : PartialOrder A
inst✝² : StarOrderedRing A
inst✝¹ : NonUnitalIsometricContinuousFunctionalCalculus ℝ A IsSelfAdjoint
inst✝ : NonnegSpectrumClass ℝ A
f : ℝ≥0 → ℝ≥0
a : A
x : ℝ≥0
hf : ContinuousOn f (σₙ ℝ≥0 a)
hf0 : f 0 = 0
ha : 0 ≤ a
⊢ x ∈ σₙ ℝ≥0 a → f x ≤ ‖cfcₙ f a‖₊

Tactic:
exact (IsGreatest.nnnorm_cfcₙ_nnreal f a hf hf0 ha |>.2 ⟨x, ·, rfl⟩)

Goal state after:
Module: Mathlib.Topology.Sets.VietorisTopology

Goal state before:
pp: α : Type u_1
β : Type u_2
γ : Type u_3
inst✝² : TopologicalSpace α
inst✝¹ : TopologicalSpace β
inst✝ : TopologicalSpace γ
f : α → Compacts β
g : α → β → γ
hf : Continuous[inst✝², _] f
hg : Continuous[instTopologicalSpaceProd, inst✝] (Function.uncurry g)
⊢ Continuous[inst✝², _] fun x ↦ Compacts.map (g x) ⋯ (f x)

Tactic:
conv in Compacts.map _ _ _ => equals ({x} ×ˢ f x).map g.uncurry hg => ext; simp
  have := hg.compacts_map
  fun_prop

Goal state after:
Module: Mathlib.Topology.Sets.VietorisTopology

Goal state before:
pp: α : Type u_1
β : Type u_2
γ : Type u_3
inst✝³ : TopologicalSpace α
inst✝² : TopologicalSpace β
inst✝¹ : TopologicalSpace γ
f : α → β
inst✝ : RegularSpace α
⊢ ∀
    t ∈
      (fun x ↦ SetLike.coe ⁻¹' 𝒫 x) '' {U | IsOpen[inst✝³] U} ∪
        (fun x ↦ SetLike.coe ⁻¹' {s | (s ∩ x).Nonempty}) '' {U | IsOpen[inst✝³] U},
    ∀ a ∈ t, Disjoint (𝓝ˢ tᶜ) (𝓝 a)

Tactic:
powerset,

Goal state after:
α : Type u_1
β : Type u_2
γ : Type u_3
inst✝³ : TopologicalSpace α
inst✝² : TopologicalSpace β
inst✝¹ : TopologicalSpace γ
f : α → β
inst✝ : RegularSpace α
⊢ ∀
    t ∈
      (fun x ↦ SetLike.coe ⁻¹' {t | t ⊆ x}) '' {U | IsOpen[inst✝³] U} ∪
        (fun x ↦ SetLike.coe ⁻¹' {s | (s ∩ x).Nonempty}) '' {U | IsOpen[inst✝³] U},
    ∀ a ∈ t, Disjoint (𝓝ˢ tᶜ) (𝓝 a)
Module: Mathlib.Analysis.LocallyConvex.AbsConvex

Goal state before:
pp: case mp
𝕜 : Type u_1
E : Type u_2
inst✝³ : SeminormedRing 𝕜
inst✝² : SMul 𝕜 E
inst✝¹ : AddCommMonoid E
inst✝ : PartialOrder 𝕜
s : Set E
h : (absConvexHull 𝕜) s = ∅
⊢ s = ∅

Tactic:
rw [← Set.subset_empty_iff, ← h]

Goal state after:
case mp
𝕜 : Type u_1
E : Type u_2
inst✝³ : SeminormedRing 𝕜
inst✝² : SMul 𝕜 E
inst✝¹ : AddCommMonoid E
inst✝ : PartialOrder 𝕜
s : Set E
h : (absConvexHull 𝕜) s = ∅
⊢ s ⊆ (absConvexHull 𝕜) s
Module: Mathlib.Analysis.Normed.Operator.BanachSteinhaus

Goal state before:
pp: E : Type u_1
F : Type u_2
𝕜 : Type u_3
𝕜₂ : Type u_4
inst✝⁷ : SeminormedAddCommGroup E
inst✝⁶ : SeminormedAddCommGroup F
inst✝⁵ : NontriviallyNormedField 𝕜
inst✝⁴ : NontriviallyNormedField 𝕜₂
inst✝³ : NormedSpace 𝕜 E
inst✝² : NormedSpace 𝕜₂ F
σ₁₂ : 𝕜 →+* 𝕜₂
inst✝¹ : RingHomIsometric σ₁₂
ι : Type u_5
inst✝ : CompleteSpace E
g : ι → E →SL[σ₁₂] F
h : ∀ (x : E), ⨆ i, ↑‖(g i) x‖₊ < ∞
⊢ ⨆ i, ↑‖g i‖₊ < ∞

Tactic:
rw [show ((⨆ i, ↑‖g i‖₊) < ∞) ↔ _ from (NormedSpace.equicontinuous_TFAE g).out 8 2]
  refine (norm_withSeminorms 𝕜₂ F).banach_steinhaus (fun _ x ↦ ?_)
  simpa [← NNReal.bddAbove_coe, ← Set.range_comp] using! ENNReal.iSup_coe_lt_top.1 (h x)

Goal state after:
Module: Mathlib.Analysis.Normed.Affine.AddTorsor

Goal state before:
pp: V : Type u_1
P : Type u_2
inst✝⁵ : SeminormedAddCommGroup V
inst✝⁴ : PseudoMetricSpace P
inst✝³ : NormedAddTorsor V P
𝕜 : Type u_5
inst✝² : NormedField 𝕜
inst✝¹ : NormedSpace 𝕜 V
inst✝ : Invertible 2
p₁ p₂ p₃ p₄ : P
⊢ ‖2‖⁻¹ * ‖p₁ -ᵥ p₃ + (p₂ -ᵥ p₄)‖ ≤ (‖p₁ -ᵥ p₃‖ + ‖p₂ -ᵥ p₄‖) / ‖2‖

Tactic:
← div_eq_inv_mul

Goal state after:
V : Type u_1
P : Type u_2
inst✝⁵ : SeminormedAddCommGroup V
inst✝⁴ : PseudoMetricSpace P
inst✝³ : NormedAddTorsor V P
𝕜 : Type u_5
inst✝² : NormedField 𝕜
inst✝¹ : NormedSpace 𝕜 V
inst✝ : Invertible 2
p₁ p₂ p₃ p₄ : P
⊢ ‖p₁ -ᵥ p₃ + (p₂ -ᵥ p₄)‖ / ‖2‖ ≤ (‖p₁ -ᵥ p₃‖ + ‖p₂ -ᵥ p₄‖) / ‖2‖
Module: Mathlib.Topology.ContinuousMap.Ideals

Goal state before:
pp: X : Type u_1
R : Type u_2
inst✝⁴ : TopologicalSpace X
inst✝³ : Semiring R
inst✝² : TopologicalSpace R
inst✝¹ : IsTopologicalSemiring R
inst✝ : T2Space R
s : Set X
⊢ IsClosed ↑(idealOfSet R s)

Tactic:
simp only [idealOfSet, Submodule.coe_set_mk, Set.ofPred_forall]

Goal state after:
X : Type u_1
R : Type u_2
inst✝⁴ : TopologicalSpace X
inst✝³ : Semiring R
inst✝² : TopologicalSpace R
inst✝¹ : IsTopologicalSemiring R
inst✝ : T2Space R
s : Set X
⊢ IsClosed ↑{ carrier := ⋂ i ∈ sᶜ, {x | x i = 0}, add_mem' := ⋯, zero_mem' := ⋯ }
Module: Mathlib.Topology.ContinuousMap.Ideals

Goal state before:
pp: X : Type u_1
𝕜 : Type u_2
inst✝³ : RCLike 𝕜
inst✝² : TopologicalSpace X
inst✝¹ : CompactSpace X
inst✝ : T2Space X
I : Ideal C(X, 𝕜)
f : C(X, 𝕜)
hf : f ∈ idealOfSet 𝕜 (setOfIdeal I)
ε : ℝ≥0
hε : 0 < ε
t : Set X := {x | ε / 2 ≤ ‖f x‖₊}
ht : IsClosed t
htI : Disjoint t (setOfIdeal I)ᶜ
g : C(X, ℝ≥0)
hgI : (↑(algebraMapCLM ℝ≥0 𝕜)).comp g ∈ I
hg : ∀ (x : X), g x ≤ 1
hgt : Set.EqOn (⇑g) 1 t
x : X
⊢ ‖f x - f x * ((↑(algebraMapCLM ℝ≥0 𝕜)).comp g) x‖₊ < ε

Tactic:
by_cases hx : x ∈ t

Goal state after:
case pos
X : Type u_1
𝕜 : Type u_2
inst✝³ : RCLike 𝕜
inst✝² : TopologicalSpace X
inst✝¹ : CompactSpace X
inst✝ : T2Space X
I : Ideal C(X, 𝕜)
f : C(X, 𝕜)
hf : f ∈ idealOfSet 𝕜 (setOfIdeal I)
ε : ℝ≥0
hε : 0 < ε
t : Set X := {x | ε / 2 ≤ ‖f x‖₊}
ht : IsClosed t
htI : Disjoint t (setOfIdeal I)ᶜ
g : C(X, ℝ≥0)
hgI : (↑(algebraMapCLM ℝ≥0 𝕜)).comp g ∈ I
hg : ∀ (x : X), g x ≤ 1
hgt : Set.EqOn (⇑g) 1 t
x : X
hx : x ∈ t
⊢ ‖f x - f x * ((↑(algebraMapCLM ℝ≥0 𝕜)).comp g) x‖₊ < ε

case neg
X : Type u_1
𝕜 : Type u_2
inst✝³ : RCLike 𝕜
inst✝² : TopologicalSpace X
inst✝¹ : CompactSpace X
inst✝ : T2Space X
I : Ideal C(X, 𝕜)
f : C(X, 𝕜)
hf : f ∈ idealOfSet 𝕜 (setOfIdeal I)
ε : ℝ≥0
hε : 0 < ε
t : Set X := {x | ε / 2 ≤ ‖f x‖₊}
ht : IsClosed t
htI : Disjoint t (setOfIdeal I)ᶜ
g : C(X, ℝ≥0)
hgI : (↑(algebraMapCLM ℝ≥0 𝕜)).comp g ∈ I
hg : ∀ (x : X), g x ≤ 1
hgt : Set.EqOn (⇑g) 1 t
x : X
hx : x ∉ t
⊢ ‖f x - f x * ((↑(algebraMapCLM ℝ≥0 𝕜)).comp g) x‖₊ < ε
Module: Mathlib.Topology.UrysohnsLemma

Goal state before:
pp: case refine_2
X : Type u_1
inst✝² : TopologicalSpace X
inst✝¹ : RegularSpace X
inst✝ : LocallyCompactSpace X
s t : Set X
hs : IsCompact s
ht : IsClosed[inst✝²] t
hd : Disjoint s t
k : Set X
k_comp : IsCompact k
k_closed : IsClosed[inst✝²] k
sk : s ⊆ interior k
kt : k ⊆ tᶜ
f : X → ℝ
hf : Continuous[inst✝², _] f
hfs : EqOn (⇑{ toFun := f, continuous_toFun := hf }) 0 s
hft : EqOn (⇑{ toFun := f, continuous_toFun := hf }) 1 (interior k)ᶜ
h'f : ∀ (x : X), { toFun := f, continuous_toFun := hf } x ∈ Icc 0 1
A : t ⊆ (interior k)ᶜ
x : X
⊢ { toFun := fun x ↦ 1 - f x, continuous_toFun := ⋯ } x ∈ Icc 0 1

Tactic:
have : 0 ≤ f x ∧ f x ≤ 1 := by simpa using h'f x

Goal state after:
case refine_2
X : Type u_1
inst✝² : TopologicalSpace X
inst✝¹ : RegularSpace X
inst✝ : LocallyCompactSpace X
s t : Set X
hs : IsCompact s
ht : IsClosed[inst✝²] t
hd : Disjoint s t
k : Set X
k_comp : IsCompact k
k_closed : IsClosed[inst✝²] k
sk : s ⊆ interior k
kt : k ⊆ tᶜ
f : X → ℝ
hf : Continuous[inst✝², _] f
hfs : EqOn (⇑{ toFun := f, continuous_toFun := hf }) 0 s
hft : EqOn (⇑{ toFun := f, continuous_toFun := hf }) 1 (interior k)ᶜ
h'f : ∀ (x : X), { toFun := f, continuous_toFun := hf } x ∈ Icc 0 1
A : t ⊆ (interior k)ᶜ
x : X
this : 0 ≤ f x ∧ f x ≤ 1
⊢ { toFun := fun x ↦ 1 - f x, continuous_toFun := ⋯ } x ∈ Icc 0 1
Module: Mathlib.Analysis.CStarAlgebra.GelfandDuality

Goal state before:
pp: A : Type u_1
inst✝ : CommCStarAlgebra A
a : A
this : spectralRadius ℂ (star ((gelfandTransform ℂ A) a) * (gelfandTransform ℂ A) a) = ↑‖star a * a‖₊
⊢ ‖(gelfandTransform ℂ A) a‖ = ‖a‖

Tactic:
(IsSelfAdjoint.star_mul_self (gelfandTransform ℂ A a)).spectralRadius_eq_nnnorm

Goal state after:
A : Type u_1
inst✝ : CommCStarAlgebra A
a : A
this : ↑‖star ((gelfandTransform ℂ A) a) * (gelfandTransform ℂ A) a‖₊ = ↑‖star a * a‖₊
⊢ ‖(gelfandTransform ℂ A) a‖ = ‖a‖
Module: Mathlib.Analysis.SpecialFunctions.ContinuousFunctionalCalculus.PosPart.Basic

Goal state before:
pp: A : Type u_1
inst✝⁹ : NonUnitalRing A
inst✝⁸ : Module ℝ A
inst✝⁷ : SMulCommClass ℝ A A
inst✝⁶ : IsScalarTower ℝ A A
inst✝⁵ : StarRing A
inst✝⁴ : TopologicalSpace A
inst✝³ : NonUnitalContinuousFunctionalCalculus ℝ A IsSelfAdjoint
inst✝² : PartialOrder A
inst✝¹ : StarOrderedRing A
inst✝ : NonnegSpectrumClass ℝ A
a : A
ha : IsSelfAdjoint a
⊢ a⁻ = 0 ↔ 0 ≤ a

Tactic:
← posPart_eq_self,

Goal state after:
A : Type u_1
inst✝⁹ : NonUnitalRing A
inst✝⁸ : Module ℝ A
inst✝⁷ : SMulCommClass ℝ A A
inst✝⁶ : IsScalarTower ℝ A A
inst✝⁵ : StarRing A
inst✝⁴ : TopologicalSpace A
inst✝³ : NonUnitalContinuousFunctionalCalculus ℝ A IsSelfAdjoint
inst✝² : PartialOrder A
inst✝¹ : StarOrderedRing A
inst✝ : NonnegSpectrumClass ℝ A
a : A
ha : IsSelfAdjoint a
⊢ a⁻ = 0 ↔ a⁺ = a