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}
x y : X
⊢ U x y ∈ 𝓝 y

Tactic:
refine IsOpen.mem_nhds ?_ ?_

Goal state after:
case refine_1
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}
x y : X
⊢ IsOpen[inst✝¹] (U x y)

case refine_2
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}
x y : X
⊢ y ∈ U x y
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}
x : X
⊢ W x ∈ 𝓝 x

Tactic:
refine IsOpen.mem_nhds ?_ ?_

Goal state after:
case refine_1
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}
x : X
⊢ IsOpen[inst✝¹] (W x)

case refine_2
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}
x : X
⊢ x ∈ W x
Module: Mathlib.Topology.ContinuousMap.StoneWeierstrass

Goal state before:
pp: case pos.left
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 := ⋯
U_nhds_y : ∀ (x y : X), U x y ∈ 𝓝 y
ys : X → Finset X := ⋯
ys_w : ∀ (x : X), ⋃ y ∈ ys x, U x y = ⊤ := ⋯
ys_nonempty : ∀ (x : X), (ys x).Nonempty
h : X → ↑L := ⋯
lt_h : ∀ (x z : X), f z - ε < ↑(h x) z
h_eq : ∀ (x : X), ↑(h x) x = f x
W : X → Set X := ⋯
W_nhds : ∀ (x : X), W x ∈ 𝓝 x
xs : Finset X := ⋯
xs_w : ⋃ x ∈ xs, W x = ⊤ := ⋯
xs_nonempty : xs.Nonempty
k : ↑L := ⋯
z : X
⊢ ↑k z < f z + ε

Tactic:
simp only [k, Finset.inf'_lt_iff, ContinuousMap.inf'_apply]
    exact Set.exists_set_mem_of_union_eq_top _ _ xs_w z

Goal state after:
Module: Mathlib.Analysis.CStarAlgebra.Unitization

Goal state before:
pp: 𝕜 : Type u_1
E : Type u_2
inst✝⁸ : DenselyNormedField 𝕜
inst✝⁷ : NonUnitalNormedRing E
inst✝⁶ : StarRing E
inst✝⁵ : CStarRing E
inst✝⁴ : NormedSpace 𝕜 E
inst✝³ : IsScalarTower 𝕜 E E
inst✝² : SMulCommClass 𝕜 E E
inst✝¹ : StarRing 𝕜
inst✝ : StarModule 𝕜 E
x : Unitization 𝕜 E
b : E
hb : b ∈ Metric.closedBall 0 1
⊢ ‖b⋆ * x.toProd.1⋆ • (x.toProd.1 • b + x.toProd.2 * b) + b⋆ * x.toProd.2⋆ * (x.toProd.1 • b + x.toProd.2 * b)‖ ≤
    ‖(algebraMap 𝕜 (E →L[𝕜] E)) (x⋆ * x).toProd.1 + (mul 𝕜 E) (x⋆ * x).toProd.2‖

Tactic:
mul_assoc,

Goal state after:
𝕜 : Type u_1
E : Type u_2
inst✝⁸ : DenselyNormedField 𝕜
inst✝⁷ : NonUnitalNormedRing E
inst✝⁶ : StarRing E
inst✝⁵ : CStarRing E
inst✝⁴ : NormedSpace 𝕜 E
inst✝³ : IsScalarTower 𝕜 E E
inst✝² : SMulCommClass 𝕜 E E
inst✝¹ : StarRing 𝕜
inst✝ : StarModule 𝕜 E
x : Unitization 𝕜 E
b : E
hb : b ∈ Metric.closedBall 0 1
⊢ ‖b⋆ * x.toProd.1⋆ • (x.toProd.1 • b + x.toProd.2 * b) + b⋆ * (x.toProd.2⋆ * (x.toProd.1 • b + x.toProd.2 * b))‖ ≤
    ‖(algebraMap 𝕜 (E →L[𝕜] E)) (x⋆ * x).toProd.1 + (mul 𝕜 E) (x⋆ * x).toProd.2‖
Module: Mathlib.Analysis.CStarAlgebra.Unitization

Goal state before:
pp: case h₁
𝕜 : Type u_1
E : Type u_2
inst✝⁸ : DenselyNormedField 𝕜
inst✝⁷ : NonUnitalNormedRing E
inst✝⁶ : StarRing E
inst✝⁵ : CStarRing E
inst✝⁴ : NormedSpace 𝕜 E
inst✝³ : IsScalarTower 𝕜 E E
inst✝² : SMulCommClass 𝕜 E E
inst✝¹ : StarRing 𝕜
inst✝ : StarModule 𝕜 E
x : Unitization 𝕜 E
b : E
hb : b ∈ Metric.closedBall 0 1
y : E
hy : y ∈ Metric.closedBall 0 1
⊢ ‖↑((algebraMap 𝕜 (E →L[𝕜] E)) (x⋆ * x).toProd.1) y‖ ≤ ‖(x⋆ * x).toProd.1‖

Tactic:
rw [Algebra.algebraMap_eq_smul_one]

Goal state after:
case h₁
𝕜 : Type u_1
E : Type u_2
inst✝⁸ : DenselyNormedField 𝕜
inst✝⁷ : NonUnitalNormedRing E
inst✝⁶ : StarRing E
inst✝⁵ : CStarRing E
inst✝⁴ : NormedSpace 𝕜 E
inst✝³ : IsScalarTower 𝕜 E E
inst✝² : SMulCommClass 𝕜 E E
inst✝¹ : StarRing 𝕜
inst✝ : StarModule 𝕜 E
x : Unitization 𝕜 E
b : E
hb : b ∈ Metric.closedBall 0 1
y : E
hy : y ∈ Metric.closedBall 0 1
⊢ ‖↑((x⋆ * x).toProd.1 • 1) y‖ ≤ ‖(x⋆ * x).toProd.1‖
Module: Mathlib.Topology.UniformSpace.Closeds

Goal state before:
pp: α : Type u_1
U : SetRel α α
x y : α
⊢ ({x}, {y}) ∈ hausdorffEntourage U ↔ (x, y) ∈ U

Tactic:
by
  simp [hausdorffEntourage]

Goal state after:
Module: Mathlib.Topology.UniformSpace.Closeds

Goal state before:
pp: α : Type u_1
inst✝ : UniformSpace α
⊢ UniformContinuous fun x ↦ x.1 ∪ x.2

Tactic:
refine Filter.tendsto_lift'.mpr fun U hU => ?_
  filter_upwards [entourageProd_mem_uniformity (Filter.mem_lift' hU) (Filter.mem_lift' hU)]
    with _ ⟨h₁, h₂⟩ using union_mem_hausdorffEntourage U h₁ h₂

Goal state after:
Module: Mathlib.Analysis.Normed.Algebra.Spectrum

Goal state before:
pp: case e'_3
𝕜 : Type u_1
A : Type u_2
inst✝³ : NormedField 𝕜
inst✝² : NormedRing A
inst✝¹ : NormedAlgebra 𝕜 A
inst✝ : CompleteSpace A
a : A
n : ℕ
k : 𝕜
hk : k ∈ σ a
pow_mem : k ^ (n + 1) ∈ σ (a ^ (n + 1))
nnnorm_pow_le : ↑(‖k‖₊ ^ (n + 1)) ≤ ↑‖a ^ (n + 1)‖₊ * ↑‖1‖₊
hn : 0 < ↑(n + 1)
⊢ ↑‖k‖₊ = (fun x ↦ x ^ (1 / ↑(n + 1))) ↑(‖k‖₊ ^ (n + 1))

pp: case e'_4
𝕜 : Type u_1
A : Type u_2
inst✝³ : NormedField 𝕜
inst✝² : NormedRing A
inst✝¹ : NormedAlgebra 𝕜 A
inst✝ : CompleteSpace A
a : A
n : ℕ
k : 𝕜
hk : k ∈ σ a
pow_mem : k ^ (n + 1) ∈ σ (a ^ (n + 1))
nnnorm_pow_le : ↑(‖k‖₊ ^ (n + 1)) ≤ ↑‖a ^ (n + 1)‖₊ * ↑‖1‖₊
hn : 0 < ↑(n + 1)
⊢ ↑‖a ^ (n + 1)‖₊ ^ (1 / (↑n + 1)) * ↑‖1‖₊ ^ (1 / (↑n + 1)) = (fun x ↦ x ^ (1 / ↑(n + 1))) (↑‖a ^ (n + 1)‖₊ * ↑‖1‖₊)

Tactic:
all_goals dsimp

Goal state after:
case e'_3
𝕜 : Type u_1
A : Type u_2
inst✝³ : NormedField 𝕜
inst✝² : NormedRing A
inst✝¹ : NormedAlgebra 𝕜 A
inst✝ : CompleteSpace A
a : A
n : ℕ
k : 𝕜
hk : k ∈ σ a
pow_mem : k ^ (n + 1) ∈ σ (a ^ (n + 1))
nnnorm_pow_le : ↑(‖k‖₊ ^ (n + 1)) ≤ ↑‖a ^ (n + 1)‖₊ * ↑‖1‖₊
hn : 0 < ↑(n + 1)
⊢ ↑‖k‖₊ = (↑‖k‖₊ ^ (n + 1)) ^ (1 / ↑(n + 1))

case e'_4
𝕜 : Type u_1
A : Type u_2
inst✝³ : NormedField 𝕜
inst✝² : NormedRing A
inst✝¹ : NormedAlgebra 𝕜 A
inst✝ : CompleteSpace A
a : A
n : ℕ
k : 𝕜
hk : k ∈ σ a
pow_mem : k ^ (n + 1) ∈ σ (a ^ (n + 1))
nnnorm_pow_le : ↑(‖k‖₊ ^ (n + 1)) ≤ ↑‖a ^ (n + 1)‖₊ * ↑‖1‖₊
hn : 0 < ↑(n + 1)
⊢ ↑‖a ^ (n + 1)‖₊ ^ (1 / (↑n + 1)) * ↑‖1‖₊ ^ (1 / (↑n + 1)) = (↑‖a ^ (n + 1)‖₊ * ↑‖1‖₊) ^ (1 / ↑(n + 1))
Module: Mathlib.Analysis.Normed.Algebra.Spectrum

Goal state before:
pp: case pos
𝕜 : Type u_1
A : Type u_2
inst✝³ : NontriviallyNormedField 𝕜
inst✝² : NormedRing A
inst✝¹ : NormedAlgebra 𝕜 A
inst✝ : HasSummableGeomSeries A
a : A
r : ℝ≥0
hr : ↑r < (↑‖a‖₊)⁻¹
n : ℕ
h : ‖a‖₊ = 0
⊢ ‖a‖₊ ^ n.succ * r ^ (n + 1) ≤ 1

pp: case neg
𝕜 : Type u_1
A : Type u_2
inst✝³ : NontriviallyNormedField 𝕜
inst✝² : NormedRing A
inst✝¹ : NormedAlgebra 𝕜 A
inst✝ : HasSummableGeomSeries A
a : A
r : ℝ≥0
hr : ↑r < (↑‖a‖₊)⁻¹
n : ℕ
h : ¬‖a‖₊ = 0
⊢ ‖a‖₊ ^ n.succ * r ^ (n + 1) ≤ 1

Tactic:
· simp [h, pow_succ']

Goal state after:
case neg
𝕜 : Type u_1
A : Type u_2
inst✝³ : NontriviallyNormedField 𝕜
inst✝² : NormedRing A
inst✝¹ : NormedAlgebra 𝕜 A
inst✝ : HasSummableGeomSeries A
a : A
r : ℝ≥0
hr : ↑r < (↑‖a‖₊)⁻¹
n : ℕ
h : ¬‖a‖₊ = 0
⊢ ‖a‖₊ ^ n.succ * r ^ (n + 1) ≤ 1
Module: Mathlib.Topology.Sets.VietorisTopology

Goal state before:
pp: α : Type u_1
inst✝ : TopologicalSpace α
K : Set α
hK : IsCompact K
s : Set (Set α)
hsK : s ⊆ 𝒫 K
hs : ∀ L ∈ s, IsCompact L
⊢ IsCompact {t | t ⊆ K ∧ ∀ L ∈ s, (t ∩ L).Nonempty}

Tactic:
refine isCompact_generateFrom rfl fun S hS hKS => ?_
  let u := {U | IsOpen U ∧ {s | (s ∩ U).Nonempty} ∈ S}
  by_cases! hsu : ∃ L ∈ s, L ⊆ ⋃₀ u
  · /- If the open sets `Uⱼ` in the hit conditions `t ∩ Uⱼ ≠ ∅` cover some `Lᵢ`, then every set
    intersecting `Lᵢ` also intersects some `Uⱼ`. This `Uⱼ` can be chosen from a finite subfamily by
    the compactness of `Lᵢ`. -/
    obtain ⟨L, hL, hLu⟩ := hsu
    rw [sUnion_eq_biUnion] at hLu
    obtain ⟨T, hTS, hT, hLT⟩ := (hs L hL).elim_finite_subcover_image (fun _ h => h.1) hLu
    refine ⟨(fun U => {s | (s ∩ U).Nonempty}) '' T, by grind [image_subset_iff], hT.image _, ?_⟩
    simp_rw [sUnion_image, ← ofPred_exists, ← nonempty_iUnion, ← inter_iUnion]
    grw [← hLT]
    grind
  · -- Otherwise, the set `K \ ⋃ Uⱼ` intersects every `Lᵢ`, so it is in one of the covering sets.
    simp_rw [← sdiff_nonempty] at hsu
    replace hsu L (h : L ∈ s) : (K \ ⋃₀ u ∩ L).Nonempty := (hsu L h).mono <| by grind
    obtain ⟨_, hUS, hUu⟩ := mem_sUnion.mp <| hKS ⟨sdiff_subset, hsu⟩
    rcases hS hUS with ⟨U, hU, rfl⟩ | ⟨U, hU, rfl⟩
    · /- If `K \ ⋃ Uⱼ ⊆ U`, then every subset of `K` is either a subset of `U` or intersects some
      `Uⱼ`. By the compactness of `K \ U`, `Uⱼ` can be chosen from a finite subfamily. -/
      rw [mem_powerset_iff, sdiff_subset_comm, sUnion_eq_biUnion] at hUu
      obtain ⟨T, hTS, hT, hKT⟩ := (hK.diff hU).elim_finite_subcover_image (fun _ h => h.1) hUu
      refine ⟨insert U.powerset ((fun V => {s | (s ∩ V).Nonempty}) '' T),
        insert_subset hUS <| Set.image_subset_iff.mpr <| hTS.trans fun _ h => h.2,
        (hT.image _).insert _, ?_⟩
      rw [sUnion_insert, ← sdiff_subset_iff, sUnion_image]
      rintro t ⟨⟨htK, -⟩, htU⟩
      rw [mem_powerset_iff, not_subset] at htU
      obtain ⟨x, hxt, hxU⟩ := htU
      obtain ⟨V, hVT, hxV⟩ := mem_iUnion₂.mp <| hKT ⟨htK hxt, hxU⟩
      exact mem_biUnion hVT ⟨x, hxt, hxV⟩
    · -- `K \ ⋃ Uⱼ` is disjoint from every `Uⱼ`, so it cannot satisfy any of the hit conditions.
      obtain ⟨x, hxu, hxU⟩ := hUu
      cases hxu.2 <| mem_sUnion_of_mem hxU ⟨hU, hUS⟩

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

Goal state before:
pp: case refine_2.inl
α : Type u_1
inst✝ : TopologicalSpace α
s t : Set α
x✝ : (∀ x ∈ s, ∃ y ∈ t, x ⤳ y) ∧ t ⊆ closure[inst✝] s
hst : ∀ x ∈ s, ∃ y ∈ t, x ⤳ y
hts : t ⊆ closure[inst✝] s
U : Set α
hU : U ∈ {U | IsOpen[inst✝] U}
hs : t ∈ 𝒫 U
⊢ ⨅
      s_1 ∈
        {s_2 |
          s ∈ s_2 ∧
            s_2 ∈ powerset '' {U | IsOpen[inst✝] U} ∪ (fun V ↦ {s | (s ∩ V).Nonempty}) '' {V | IsOpen[inst✝] V}},
      Filter.principal s_1 ≤
    Filter.principal (𝒫 U)

pp: case refine_2.inr
α : Type u_1
inst✝ : TopologicalSpace α
s t : Set α
x✝ : (∀ x ∈ s, ∃ y ∈ t, x ⤳ y) ∧ t ⊆ closure[inst✝] s
hst : ∀ x ∈ s, ∃ y ∈ t, x ⤳ y
hts : t ⊆ closure[inst✝] s
U : Set α
hU : U ∈ {U | IsOpen[inst✝] U}
hs : t ∈ (fun V ↦ {s | (s ∩ V).Nonempty}) U
⊢ ⨅
      s_1 ∈
        {s_2 |
          s ∈ s_2 ∧
            s_2 ∈ powerset '' {U | IsOpen[inst✝] U} ∪ (fun V ↦ {s | (s ∩ V).Nonempty}) '' {V | IsOpen[inst✝] V}},
      Filter.principal s_1 ≤
    Filter.principal ((fun V ↦ {s | (s ∩ V).Nonempty}) U)

Tactic:
· refine iInf₂_le U.powerset ⟨fun x hx => ?_, .inl <| mem_image_of_mem _ hU⟩
      obtain ⟨y, hyt, hxy⟩ := hst x hx
      exact hxy.mem_open hU <| hs hyt

Goal state after:
case refine_2.inr
α : Type u_1
inst✝ : TopologicalSpace α
s t : Set α
x✝ : (∀ x ∈ s, ∃ y ∈ t, x ⤳ y) ∧ t ⊆ closure[inst✝] s
hst : ∀ x ∈ s, ∃ y ∈ t, x ⤳ y
hts : t ⊆ closure[inst✝] s
U : Set α
hU : U ∈ {U | IsOpen[inst✝] U}
hs : t ∈ (fun V ↦ {s | (s ∩ V).Nonempty}) U
⊢ ⨅
      s_1 ∈
        {s_2 |
          s ∈ s_2 ∧
            s_2 ∈ powerset '' {U | IsOpen[inst✝] U} ∪ (fun V ↦ {s | (s ∩ V).Nonempty}) '' {V | IsOpen[inst✝] V}},
      Filter.principal s_1 ≤
    Filter.principal ((fun V ↦ {s | (s ∩ V).Nonempty}) U)
Module: Mathlib.Topology.Sets.VietorisTopology

Goal state before:
pp: α : Type u_1
inst✝ : TopologicalSpace α
s : Set α
hs : IsPreconnected s
⊢ IsPreconnected {t | t.Nonempty ∧ t.Finite ∧ t ⊆ s}

Tactic:
rcases eq_empty_or_nonempty s with rfl | ⟨x, hx⟩

Goal state after:
case inl
α : Type u_1
inst✝ : TopologicalSpace α
hs : IsPreconnected ∅
⊢ IsPreconnected {t | t.Nonempty ∧ t.Finite ∧ t ⊆ ∅}

case inr
α : Type u_1
inst✝ : TopologicalSpace α
s : Set α
hs : IsPreconnected s
x : α
hx : x ∈ s
⊢ IsPreconnected {t | t.Nonempty ∧ t.Finite ∧ t ⊆ s}
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
⊢ IsUnit ((algebraMap 𝕜 ↥S) μ - x)

Tactic:
refine Subalgebra.isUnit_of_isUnit_val_of_eventually S h ?_ ?_ <| .map hμ₁ (algebraMap 𝕜 S · - x)

Goal state after:
case refine_1
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 ⊓ 𝓟 (σ 𝕜 x)ᶜ) ≤ 𝓝 ((algebraMap 𝕜 ↥S) μ - x)

case refine_2
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
⊢ ∀ᶠ (x : ↥S) in map (fun x_1 ↦ (algebraMap 𝕜 ↥S) x_1 - x) (𝓝 μ ⊓ 𝓟 (σ 𝕜 x)ᶜ), IsUnit x
Module: Mathlib.Analysis.CStarAlgebra.ContinuousFunctionalCalculus.Instances

Goal state before:
pp: A : Type u_1
inst✝⁶ : NonUnitalRing A
inst✝⁵ : StarRing A
inst✝⁴ : TopologicalSpace A
inst✝³ : Module ℝ A
inst✝² : IsScalarTower ℝ A A
inst✝¹ : SMulCommClass ℝ A A
inst✝ : NonUnitalContinuousFunctionalCalculus ℝ A IsSelfAdjoint
a : A
ha₁ : IsSelfAdjoint a
ha₂ : QuasispectrumRestricts a ⇑ContinuousMap.realToNNReal
⊢ ∃ x, IsSelfAdjoint x ∧ QuasispectrumRestricts x ⇑ContinuousMap.realToNNReal ∧ x * x = a

Tactic:
use cfcₙ (√·) a, cfcₙ_predicate (√·) a

Goal state after:
case right
A : Type u_1
inst✝⁶ : NonUnitalRing A
inst✝⁵ : StarRing A
inst✝⁴ : TopologicalSpace A
inst✝³ : Module ℝ A
inst✝² : IsScalarTower ℝ A A
inst✝¹ : SMulCommClass ℝ A A
inst✝ : NonUnitalContinuousFunctionalCalculus ℝ A IsSelfAdjoint
a : A
ha₁ : IsSelfAdjoint a
ha₂ : QuasispectrumRestricts a ⇑ContinuousMap.realToNNReal
⊢ QuasispectrumRestricts (cfcₙ (fun x ↦ √x) a) ⇑ContinuousMap.realToNNReal ∧
    cfcₙ (fun x ↦ √x) a * cfcₙ (fun x ↦ √x) a = a
Module: Mathlib.Analysis.CStarAlgebra.ContinuousFunctionalCalculus.Isometric

Goal state before:
pp: 𝕜 : Type u_1
A : Type u_2
p : A → Prop
inst✝⁴ : RCLike 𝕜
inst✝³ : NormedRing A
inst✝² : StarRing A
inst✝¹ : NormedAlgebra 𝕜 A
inst✝ : IsometricContinuousFunctionalCalculus 𝕜 A p
a : A
ha : p a
this : CompactSpace ↑(σₙ 𝕜 a)
⊢ Isometry
    ⇑↑((↑(ContinuousMap.compStarAlgHom' 𝕜 𝕜 { toFun := Set.inclusion ⋯, continuous_toFun := ⋯ })).comp
            ContinuousMapZero.toContinuousMapHom).toNonUnitalAlgHom

Tactic:
simp only [MulHom.coe_coe, NonUnitalStarAlgHom.coe_toNonUnitalAlgHom]

Goal state after:
𝕜 : Type u_1
A : Type u_2
p : A → Prop
inst✝⁴ : RCLike 𝕜
inst✝³ : NormedRing A
inst✝² : StarRing A
inst✝¹ : NormedAlgebra 𝕜 A
inst✝ : IsometricContinuousFunctionalCalculus 𝕜 A p
a : A
ha : p a
this : CompactSpace ↑(σₙ 𝕜 a)
⊢ Isometry
    ⇑((↑(ContinuousMap.compStarAlgHom' 𝕜 𝕜 { toFun := Set.inclusion ⋯, continuous_toFun := ⋯ })).comp
        ContinuousMapZero.toContinuousMapHom)
Module: Mathlib.Analysis.CStarAlgebra.ContinuousFunctionalCalculus.Isometric

Goal state before:
pp: 𝕜 : Type u_1
A : Type u_2
p : A → Prop
inst✝⁴ : RCLike 𝕜
inst✝³ : NormedRing A
inst✝² : StarRing A
inst✝¹ : NormedAlgebra 𝕜 A
inst✝ : IsometricContinuousFunctionalCalculus 𝕜 A p
a : A
ha : p a
this : CompactSpace ↑(σₙ 𝕜 a)
f : ContinuousMapZero (↑(σₙ 𝕜 a)) 𝕜
ι : C(↑(σ 𝕜 a), ↑(σₙ 𝕜 a)) := { toFun := Set.inclusion ⋯, continuous_toFun := ⋯ }
⊢ ∀ (x : ↑(σ 𝕜 a)), ‖((↑f).comp ι) x‖ ≤ ‖↑f‖

pp: 𝕜 : Type u_1
A : Type u_2
p : A → Prop
inst✝⁴ : RCLike 𝕜
inst✝³ : NormedRing A
inst✝² : StarRing A
inst✝¹ : NormedAlgebra 𝕜 A
inst✝ : IsometricContinuousFunctionalCalculus 𝕜 A p
a : A
ha : p a
this : CompactSpace ↑(σₙ 𝕜 a)
f : ContinuousMapZero (↑(σₙ 𝕜 a)) 𝕜
ι : C(↑(σ 𝕜 a), ↑(σₙ 𝕜 a)) := { toFun := Set.inclusion ⋯, continuous_toFun := ⋯ }
⊢ ∀ (x : ↑(σₙ 𝕜 a)), ‖↑f x‖ ≤ ‖(↑f).comp ι‖

Tactic:
· rintro ⟨x, hx⟩
      exact (f : C(σₙ 𝕜 a, 𝕜)).norm_coe_le_norm ⟨x, spectrum_subset_quasispectrum 𝕜 a hx⟩

Goal state after:
𝕜 : Type u_1
A : Type u_2
p : A → Prop
inst✝⁴ : RCLike 𝕜
inst✝³ : NormedRing A
inst✝² : StarRing A
inst✝¹ : NormedAlgebra 𝕜 A
inst✝ : IsometricContinuousFunctionalCalculus 𝕜 A p
a : A
ha : p a
this : CompactSpace ↑(σₙ 𝕜 a)
f : ContinuousMapZero (↑(σₙ 𝕜 a)) 𝕜
ι : C(↑(σ 𝕜 a), ↑(σₙ 𝕜 a)) := { toFun := Set.inclusion ⋯, continuous_toFun := ⋯ }
⊢ ∀ (x : ↑(σₙ 𝕜 a)), ‖↑f x‖ ≤ ‖(↑f).comp ι‖
Module: Mathlib.LinearAlgebra.AffineSpace.Ordered

Goal state before:
pp: k : Type u_1
E : Type u_2
inst✝⁸ : Ring k
inst✝⁷ : PartialOrder k
inst✝⁶ : IsOrderedRing k
inst✝⁵ : AddCommGroup E
inst✝⁴ : PartialOrder E
inst✝³ : IsOrderedAddMonoid E
inst✝² : Module k E
inst✝¹ : IsStrictOrderedModule k E
a b : E
r : k
inst✝ : PosSMulReflectLT k E
h : r < 1
⊢ (lineMap a b) r < b ↔ (lineMap a b) r < (lineMap a b) 1

Tactic:
rw [lineMap_apply_one]

Goal state after:
Module: Mathlib.LinearAlgebra.AffineSpace.Ordered

Goal state before:
pp: k : Type u_1
E : Type u_2
inst✝⁷ : Ring k
inst✝⁶ : LinearOrder k
inst✝⁵ : IsStrictOrderedRing k
inst✝⁴ : AddCommGroup E
inst✝³ : PartialOrder E
inst✝² : IsOrderedAddMonoid E
inst✝¹ : Module k E
inst✝ : IsStrictOrderedModule k E
a b : E
r : k
h : a < b
⊢ a ≤ (lineMap a b) r ↔ 0 ≤ r

Tactic:
by
  rw [← lineMap_le_lineMap_iff_of_lt' h, lineMap_apply_zero]

Goal state after:
Module: Mathlib.LinearAlgebra.AffineSpace.Ordered

Goal state before:
pp: k : Type u_1
E : Type u_2
inst✝⁷ : Ring k
inst✝⁶ : LinearOrder k
inst✝⁵ : IsStrictOrderedRing k
inst✝⁴ : AddCommGroup E
inst✝³ : PartialOrder E
inst✝² : IsOrderedAddMonoid E
inst✝¹ : Module k E
inst✝ : IsStrictOrderedModule k E
a b : E
r : k
h : a < b
⊢ (lineMap a b) r ≤ a ↔ r ≤ 0

Tactic:
by
  rw [← lineMap_le_lineMap_iff_of_lt' h, lineMap_apply_zero]

Goal state after:
Module: Mathlib.LinearAlgebra.AffineSpace.Ordered

Goal state before:
pp: k : Type u_1
E : Type u_2
inst✝⁸ : Field k
inst✝⁷ : LinearOrder k
inst✝⁶ : IsStrictOrderedRing k
inst✝⁵ : AddCommGroup E
inst✝⁴ : PartialOrder E
inst✝³ : IsOrderedAddMonoid E
inst✝² : Module k E
inst✝¹ : IsStrictOrderedModule k E
inst✝ : PosSMulReflectLE k E
a b : E
r : k
h : r < 1
⊢ (lineMap a b) r ≤ b ↔ (lineMap a b) r ≤ (lineMap a b) 1

Tactic:
rw [lineMap_apply_one]

Goal state after:
Module: Mathlib.Analysis.Normed.Module.WeakDual

Goal state before:
pp: α : Type u_4
𝕜 : Type u_5
E : Type u_6
F : Type u_7
inst✝⁵ : TopologicalSpace α
inst✝⁴ : RCLike 𝕜
inst✝³ : AddCommGroup E
inst✝² : Module 𝕜 E
inst✝¹ : AddCommGroup F
inst✝ : Module 𝕜 F
B : E →ₗ[𝕜] F →ₗ[𝕜] 𝕜
g : α → WeakBilin B
h : ∀ (y : F), Continuous[inst✝⁵, _] fun a ↦ re ((B (g a)) y)
x : F
⊢ Continuous[inst✝⁵, PseudoMetricSpace.toUniformSpace.toTopologicalSpace] fun a ↦ (B (g a)) x

Tactic:
suffices Continuous fun a ↦ (re (B (g a) x) : 𝕜) - re (B (g a) ((I : 𝕜) • x)) * I by simpa

Goal state after:
α : Type u_4
𝕜 : Type u_5
E : Type u_6
F : Type u_7
inst✝⁵ : TopologicalSpace α
inst✝⁴ : RCLike 𝕜
inst✝³ : AddCommGroup E
inst✝² : Module 𝕜 E
inst✝¹ : AddCommGroup F
inst✝ : Module 𝕜 F
B : E →ₗ[𝕜] F →ₗ[𝕜] 𝕜
g : α → WeakBilin B
h : ∀ (y : F), Continuous[inst✝⁵, _] fun a ↦ re ((B (g a)) y)
x : F
⊢ Continuous[inst✝⁵, PseudoMetricSpace.toUniformSpace.toTopologicalSpace] fun a ↦
    ↑(re ((B (g a)) x)) - ↑(re ((B (g a)) (I • x))) * I
Module: Mathlib.Topology.UrysohnsLemma

Goal state before:
pp: case h.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
g : C(X, ℝ)
hgs : EqOn (⇑g) 0 s
hgt : EqOn (⇑g) 1 t
hicc : ∀ (x : X), 0 ≤ g x ∧ g x ≤ 1
⊢ EqOn (⇑(1 - g)) 1 s

Tactic:
intro x hx
    simp only [ContinuousMap.sub_apply, ContinuousMap.one_apply, Pi.one_apply, sub_eq_self]
    exact hgs hx

Goal state after: