mathlib-initiative/mathlib-tactics huggingface dataset:
Module: Mathlib.Topology.Algebra.PontryaginDual

Goal state before:
pp: case refine_1
A : Type u_1
B : Type u_2
C : Type u_3
G : Type u_4
H : Type u_5
inst✝¹² : Monoid A
inst✝¹¹ : Monoid B
inst✝¹⁰ : Monoid C
inst✝⁹ : CommGroup G
inst✝⁸ : Group H
inst✝⁷ : TopologicalSpace A
inst✝⁶ : TopologicalSpace B
inst✝⁵ : TopologicalSpace C
inst✝⁴ : TopologicalSpace G
inst✝³ : TopologicalSpace H
inst✝² : IsTopologicalGroup G
inst✝¹ : IsTopologicalGroup H
inst✝ : CompactSpace A
V : Set (PontryaginDual A) := {ψ | Set.MapsTo (⇑ψ) Set.univ (Circle.centeredArc (π / 2))}
hVopen : IsOpen V
ψ : PontryaginDual A
hψ : ψ ∈ V
⊢ ψ = 1

pp: case refine_2
A : Type u_1
B : Type u_2
C : Type u_3
G : Type u_4
H : Type u_5
inst✝¹² : Monoid A
inst✝¹¹ : Monoid B
inst✝¹⁰ : Monoid C
inst✝⁹ : CommGroup G
inst✝⁸ : Group H
inst✝⁷ : TopologicalSpace A
inst✝⁶ : TopologicalSpace B
inst✝⁵ : TopologicalSpace C
inst✝⁴ : TopologicalSpace G
inst✝³ : TopologicalSpace H
inst✝² : IsTopologicalGroup G
inst✝¹ : IsTopologicalGroup H
inst✝ : CompactSpace A
V : Set (PontryaginDual A) := {ψ | Set.MapsTo (⇑ψ) Set.univ (Circle.centeredArc (π / 2))}
hVopen : IsOpen V
ψ : PontryaginDual A
⊢ ψ = 1 → ψ ∈ V

Tactic:
· ext1 a
      refine Circle.eq_one_of_forall_pow_mem_centeredArc_pi_div_two fun n hn ↦ ?_
      simpa using hψ (Set.mem_univ (a ^ n))

Goal state after:
case refine_2
A : Type u_1
B : Type u_2
C : Type u_3
G : Type u_4
H : Type u_5
inst✝¹² : Monoid A
inst✝¹¹ : Monoid B
inst✝¹⁰ : Monoid C
inst✝⁹ : CommGroup G
inst✝⁸ : Group H
inst✝⁷ : TopologicalSpace A
inst✝⁶ : TopologicalSpace B
inst✝⁵ : TopologicalSpace C
inst✝⁴ : TopologicalSpace G
inst✝³ : TopologicalSpace H
inst✝² : IsTopologicalGroup G
inst✝¹ : IsTopologicalGroup H
inst✝ : CompactSpace A
V : Set (PontryaginDual A) := {ψ | Set.MapsTo (⇑ψ) Set.univ (Circle.centeredArc (π / 2))}
hVopen : IsOpen V
ψ : PontryaginDual A
⊢ ψ = 1 → ψ ∈ V
Module: Mathlib.Topology.CWComplex.Classical.Graph

Goal state before:
pp: X : Type u_1
inst✝¹ : TopologicalSpace X
C : Set X
inst✝ : CWComplex C
e : cell C 1
h : (cellFrontier 1 e).Subsingleton
⊢ ∃ x, cellFrontier 1 e = closedCell 0 x

Tactic:
obtain ⟨x, y, hxy⟩ := exists_cellFrontier_one_eq e

Goal state after:
X : Type u_1
inst✝¹ : TopologicalSpace X
C : Set X
inst✝ : CWComplex C
e : cell C 1
h : (cellFrontier 1 e).Subsingleton
x y : cell C 0
hxy : cellFrontier 1 e = closedCell 0 x ∪ closedCell 0 y
⊢ ∃ x, cellFrontier 1 e = closedCell 0 x
Module: Mathlib.Topology.DerivedSet

Goal state before:
pp: X : Type u_1
inst✝¹ : TopologicalSpace X
β : Type u_2
inst✝ : TopologicalSpace β
F : Filter X
x : X
h : AccPt x F
f : X → β
hf1 : ContinuousAt f x
hf2 : Function.Injective f
⊢ AccPt (f x) (Filter.map f F)

Tactic:
by
  apply map_neBot (m := f) (hf := h) |>.mono
  rw [Filter.map_inf hf2]
  gcongr
  apply tendsto_nhdsWithin_of_tendsto_nhds_of_eventually_within _ hf1.continuousWithinAt
  simpa [hf2.eq_iff] using! eventually_mem_nhdsWithin

Goal state after:
Module: Mathlib.Topology.Category.Compactum

Goal state before:
pp: X : Compactum
A : Set X.A
F : Ultrafilter X.A
hF : F ∈ basic (cl A)
fsu : Type u_1 := Finset (Set (Ultrafilter X.A))
ssu : Type u_1 := Set (Set (Ultrafilter X.A))
ι : fsu → ssu := fun x ↦ ↑x
C0 : ssu := {Z | ∃ B ∈ F, X.str ⁻¹' B = Z}
⊢ X.str F ∈ cl A

Tactic:
let AA := { G : Ultrafilter X | A ∈ G }

Goal state after:
X : Compactum
A : Set X.A
F : Ultrafilter X.A
hF : F ∈ basic (cl A)
fsu : Type u_1 := Finset (Set (Ultrafilter X.A))
ssu : Type u_1 := Set (Set (Ultrafilter X.A))
ι : fsu → ssu := fun x ↦ ↑x
C0 : ssu := {Z | ∃ B ∈ F, X.str ⁻¹' B = Z}
AA : Set (Ultrafilter X.A) := {G | A ∈ G}
⊢ X.str F ∈ cl A
Module: Mathlib.Topology.Category.Compactum

Goal state before:
pp: X : Compactum
F : Ultrafilter X.A
x : X.A
fsu : Type u_1 := Finset (Set (Ultrafilter X.A))
ssu : Type u_1 := Set (Set (Ultrafilter X.A))
ι : fsu → ssu := fun x ↦ ↑x
T0 : ssu := {S | ∃ A ∈ F, S = basic A}
AA : Set (Ultrafilter X.A) := X.str ⁻¹' {x}
T1 : ssu := insert AA T0
T2 : Set (Set (Ultrafilter X.A)) := finiteInterClosure T1
cond : ↑F ≤ 𝓝 x
claim1 : ∀ (A : Set X.A), IsClosed A → A ∈ F → x ∈ A
⊢ X.str F = x

Tactic:
have claim2 : ∀ A : Set X, A ∈ F → x ∈ cl A := by
    intro A hA
    exact claim1 (cl A) (isClosed_cl A) (mem_of_superset hA (subset_cl A))

Goal state after:
X : Compactum
F : Ultrafilter X.A
x : X.A
fsu : Type u_1 := Finset (Set (Ultrafilter X.A))
ssu : Type u_1 := Set (Set (Ultrafilter X.A))
ι : fsu → ssu := fun x ↦ ↑x
T0 : ssu := {S | ∃ A ∈ F, S = basic A}
AA : Set (Ultrafilter X.A) := X.str ⁻¹' {x}
T1 : ssu := insert AA T0
T2 : Set (Set (Ultrafilter X.A)) := finiteInterClosure T1
cond : ↑F ≤ 𝓝 x
claim1 : ∀ (A : Set X.A), IsClosed A → A ∈ F → x ∈ A
claim2 : ∀ A ∈ F, x ∈ cl A
⊢ X.str F = x
Module: Mathlib.Topology.Category.Profinite.Product

Goal state before:
pp: ι : Type u
X : ι → Type
inst✝² : (i : ι) → TopologicalSpace (X i)
C : Set ((i : ι) → X i)
J K : ι → Prop
inst✝¹ : ∀ (i : ι), T2Space (X i)
inst✝ : ∀ (i : ι), TotallyDisconnectedSpace (X i)
hC : IsCompact C
this : CompactSpace ↑C
a : (fun X ↦ ↑X.toTop) (limitCone (indexFunctor hC)).pt
⊢ ∃ x, ∀ (J : Finset ι), (π_app C fun x ↦ x ∈ J) x = ↑a (op J)

Tactic:
have hc : ∀ (J : Finset ι) s, IsClosed ((π_app C (· ∈ J)) ⁻¹' {s}) := by
          intro J s
          refine IsClosed.preimage (π_app C (· ∈ J)).continuous ?_
          exact T1Space.t1 s

Goal state after:
ι : Type u
X : ι → Type
inst✝² : (i : ι) → TopologicalSpace (X i)
C : Set ((i : ι) → X i)
J K : ι → Prop
inst✝¹ : ∀ (i : ι), T2Space (X i)
inst✝ : ∀ (i : ι), TotallyDisconnectedSpace (X i)
hC : IsCompact C
this : CompactSpace ↑C
a : (fun X ↦ ↑X.toTop) (limitCone (indexFunctor hC)).pt
hc : ∀ (J : Finset ι) (s : ↑(obj C fun x ↦ x ∈ J)), IsClosed (⇑(π_app C fun x ↦ x ∈ J) ⁻¹' {s})
⊢ ∃ x, ∀ (J : Finset ι), (π_app C fun x ↦ x ∈ J) x = ↑a (op J)
Module: Mathlib.Topology.Category.Compactum

Goal state before:
pp: X : Type u_1
inst✝² : TopologicalSpace X
inst✝¹ : CompactSpace X
inst✝ : T2Space X
FF : Ultrafilter (Ultrafilter X)
x : X := (Ultrafilter.map Ultrafilter.lim FF).lim
c1 : x = (Ultrafilter.map Ultrafilter.lim FF).lim
c2 : ∀ (U : Set X) (F : Ultrafilter X), F.lim ∈ U → IsOpen[inst✝²] U → U ∈ F
c3 : ↑(Ultrafilter.map Ultrafilter.lim FF) ≤ 𝓝 x
U : Set X
hx : x ∈ U
hU : IsOpen[inst✝²] U
this : Ultrafilter.lim ⁻¹' U ∈ FF
⊢ {G | U ∈ G} ∈ FF

Tactic:
apply mem_of_superset this
        intro P hP
        exact c2 U P hP hU

Goal state after:
Module: Mathlib.Topology.Category.Profinite.Nobeling.Induction

Goal state before:
pp: case hf
S : Profinite
a : ↑S.toTop
⊢ ∀ ⦃a₂ : ↑S.toTop⦄, ι S a = ι S a₂ → a = a₂

Tactic:
b

Goal state after:
case hf
S : Profinite
a b : ↑S.toTop
⊢ ι S a = ι S b → a = b
Module: Mathlib.Topology.Category.Profinite.Nobeling.Successor

Goal state before:
pp: I : Type u
C : Set (I → Bool)
inst✝¹ : LinearOrder I
inst✝ : WellFoundedLT I
o : Ordinal.{u}
ho : o < Ordinal.type fun x1 x2 ↦ x1 < x2
x✝¹ : ↑(GoodProducts (π C fun x ↦ ord I x < o))
x✝ : ↑(MaxProducts C ho)
a : Products I
ha : a ∈ GoodProducts (π C fun x ↦ ord I x < o)
b : Products I
hb : a ∈ MaxProducts C ho
hab : a = b
⊢ False

Tactic:
have ha' := Products.prop_of_isGood C _ ha (term I ho) hb.2

Goal state after:
I : Type u
C : Set (I → Bool)
inst✝¹ : LinearOrder I
inst✝ : WellFoundedLT I
o : Ordinal.{u}
ho : o < Ordinal.type fun x1 x2 ↦ x1 < x2
x✝¹ : ↑(GoodProducts (π C fun x ↦ ord I x < o))
x✝ : ↑(MaxProducts C ho)
a : Products I
ha : a ∈ GoodProducts (π C fun x ↦ ord I x < o)
b : Products I
hb : a ∈ MaxProducts C ho
hab : a = b
ha' : ord I (term I ho) < o
⊢ False
Module: Mathlib.Topology.Category.Profinite.Nobeling.Successor

Goal state before:
pp: I : Type u
C : Set (I → Bool)
inst✝² : LinearOrder I
inst✝¹ : WellFoundedLT I
o : Ordinal.{u}
hsC : contained C (Order.succ o)
ho : o < Ordinal.type fun x1 x2 ↦ x1 < x2
inst✝ : Inhabited I
l : Products I
hl : ↑l ≠ []
hlh : (↑l).head! = term I ho
hlc : List.IsChain (fun x1 x2 ↦ x1 > x2) (term I ho :: ↑l.Tail)
⊢ (Linear_CC' C hsC ho) (eval C l) = eval (C' C ho) l.Tail

Tactic:
rw [max_eq_o_cons_tail' ho l hl hlh hlc, Products.evalCons]

Goal state after:
I : Type u
C : Set (I → Bool)
inst✝² : LinearOrder I
inst✝¹ : WellFoundedLT I
o : Ordinal.{u}
hsC : contained C (Order.succ o)
ho : o < Ordinal.type fun x1 x2 ↦ x1 < x2
inst✝ : Inhabited I
l : Products I
hl : ↑l ≠ []
hlh : (↑l).head! = term I ho
hlc : List.IsChain (fun x1 x2 ↦ x1 > x2) (term I ho :: ↑l.Tail)
⊢ (Linear_CC' C hsC ho) (e C (term I ho) * eval C ⟨↑l.Tail, ⋯⟩) = eval (C' C ho) (Tail ⟨term I ho :: ↑l.Tail, hlc⟩)
Module: Mathlib.Topology.CWComplex.Classical.Basic

Goal state before:
pp: X : Type u_1
t : TopologicalSpace X
C D : Set X
inst✝¹ : T2Space X
inst✝ : RelCWComplex C D
n : ℕ∞
x : X
⊢ x ∈ skeleton C n ↔ x ∈ D ∨ ∃ m, ∃ (_ : ↑m ≤ n), ∃ j, x ∈ openCell m j

Tactic:
rw [skeleton, mem_skeletonLT_iff]

Goal state after:
X : Type u_1
t : TopologicalSpace X
C D : Set X
inst✝¹ : T2Space X
inst✝ : RelCWComplex C D
n : ℕ∞
x : X
⊢ (x ∈ D ∨ ∃ m, ∃ (_ : ↑m < n + 1), ∃ j, x ∈ openCell m j) ↔ x ∈ D ∨ ∃ m, ∃ (_ : ↑m ≤ n), ∃ j, x ∈ openCell m j
Module: Mathlib.Topology.Compactness.CompactSystem

Goal state before:
pp: α : Type u_1
S : Set (Set α)
h : ∀ (C : ℕ → Set α), (∀ (i : ℕ), C i ∈ S) → (∀ (n : ℕ), (⋂ k, ⋂ (_ : k < n), C k).Nonempty) → (⋂ i, C i).Nonempty
C : ℕ → Set α
hi : ∀ (i : ℕ), C i ∈ S
h' : ∀ (n : ℕ), (dissipate C n).Nonempty
⊢ ∀ (n : ℕ), (⋂ k, ⋂ (_ : k < n), C k).Nonempty

Tactic:
Set.nonempty_iff_ne_empty

Goal state after:
α : Type u_1
S : Set (Set α)
h : ∀ (C : ℕ → Set α), (∀ (i : ℕ), C i ∈ S) → (∀ (n : ℕ), (⋂ k, ⋂ (_ : k < n), C k).Nonempty) → (⋂ i, C i).Nonempty
C : ℕ → Set α
hi : ∀ (i : ℕ), C i ∈ S
h' : ∀ (n : ℕ), dissipate C n ≠ ∅
⊢ ∀ (n : ℕ), ⋂ k, ⋂ (_ : k < n), C k ≠ ∅
Module: Mathlib.Topology.Category.Profinite.Nobeling.Successor

Goal state before:
pp: case pos
I : Type u
C : Set (I → Bool)
inst✝² : LinearOrder I
inst✝¹ : WellFoundedLT I
o : Ordinal.{u}
hsC : contained C (Order.succ o)
ho : o < Ordinal.type fun x1 x2 ↦ x1 < x2
inst✝ : Inhabited I
l : Products I
hl : ↑l ≠ []
hlh : (↑l).head! = term I ho
hlc : List.IsChain (fun x1 x2 ↦ x1 > x2) (term I ho :: ↑l.Tail)
x : ↑(C' C ho)
hi' : ∀ i ∈ ↑l.Tail, ↑x i = SwapTrue o (↑x) i
H : (∀ i ∈ ↑l.Tail, ↑x i = true) = ∀ i ∈ ↑l.Tail, SwapTrue o (↑x) i = true
h₁ : ∀ i ∈ ↑l.Tail, SwapTrue o (↑x) i = true
h₂ : ∀ i ∈ ↑(Tail ⟨term I ho :: ↑l.Tail, hlc⟩), ↑x i = true
⊢ (1 - if ↑x (term I ho) = true then 1 else 0) = 1

Tactic:
if_neg

Goal state after:
case pos
I : Type u
C : Set (I → Bool)
inst✝² : LinearOrder I
inst✝¹ : WellFoundedLT I
o : Ordinal.{u}
hsC : contained C (Order.succ o)
ho : o < Ordinal.type fun x1 x2 ↦ x1 < x2
inst✝ : Inhabited I
l : Products I
hl : ↑l ≠ []
hlh : (↑l).head! = term I ho
hlc : List.IsChain (fun x1 x2 ↦ x1 > x2) (term I ho :: ↑l.Tail)
x : ↑(C' C ho)
hi' : ∀ i ∈ ↑l.Tail, ↑x i = SwapTrue o (↑x) i
H : (∀ i ∈ ↑l.Tail, ↑x i = true) = ∀ i ∈ ↑l.Tail, SwapTrue o (↑x) i = true
h₁ : ∀ i ∈ ↑l.Tail, SwapTrue o (↑x) i = true
h₂ : ∀ i ∈ ↑(Tail ⟨term I ho :: ↑l.Tail, hlc⟩), ↑x i = true
⊢ 1 - 0 = 1

case pos.hnc
I : Type u
C : Set (I → Bool)
inst✝² : LinearOrder I
inst✝¹ : WellFoundedLT I
o : Ordinal.{u}
hsC : contained C (Order.succ o)
ho : o < Ordinal.type fun x1 x2 ↦ x1 < x2
inst✝ : Inhabited I
l : Products I
hl : ↑l ≠ []
hlh : (↑l).head! = term I ho
hlc : List.IsChain (fun x1 x2 ↦ x1 > x2) (term I ho :: ↑l.Tail)
x : ↑(C' C ho)
hi' : ∀ i ∈ ↑l.Tail, ↑x i = SwapTrue o (↑x) i
H : (∀ i ∈ ↑l.Tail, ↑x i = true) = ∀ i ∈ ↑l.Tail, SwapTrue o (↑x) i = true
h₁ : ∀ i ∈ ↑l.Tail, SwapTrue o (↑x) i = true
h₂ : ∀ i ∈ ↑(Tail ⟨term I ho :: ↑l.Tail, hlc⟩), ↑x i = true
⊢ ¬↑x (term I ho) = true
Module: Mathlib.Topology.ContinuousMap.BoundedCompactlySupported

Goal state before:
pp: case pos
α : Type u_1
γ : Type u_2
inst✝¹ : TopologicalSpace α
inst✝ : NonUnitalNormedRing γ
c : Nonempty α
f : α →ᵇ γ
h : f ∈ C_cb(α, γ)
hs : (tsupport ⇑f).Nonempty
x : α
left✝ : x ∈ tsupport ⇑f
hmax : IsMaxOn (fun x ↦ ‖f x‖) (tsupport ⇑f) x
y : α
hy : y ∈ tsupport ⇑f
⊢ ‖f y‖ ≤ ‖f x‖

Tactic:
exact hmax hy

Goal state after:
Module: Mathlib.Topology.Compactness.CountablyCompact

Goal state before:
pp: case refine_2
ι : Type u_1
E : Type u_2
F : Type u_3
inst✝³ : TopologicalSpace E
inst✝² : TopologicalSpace F
A✝ B : Set E
inst✝¹ : SequentialSpace E
inst✝ : CountablyCompactSpace E
x : ℕ → E
hx : ∀ (x_1 : E) (x_2 : ℕ → ℕ), StrictMono x_2 → ¬Tendsto (x ∘ x_2) atTop (𝓝 x_1)
A : Set E := ⋃ i, closure[inst✝³] {x i}
this✝ : IsCountablyCompact A
a : E
ha : a ∈ A ∧ MapClusterPt a atTop x
k : ℕ
hk : ∀ n > k, a ∉ closure[inst✝³] {x n}
this : a ∉ ⋃ i, closure[inst✝³] {x (i + (k + 1))}
⊢ x '' Ici (k + 1) ⊆ ⋃ i, closure[inst✝³] {x (i + (k + 1))}

Tactic:
simp only [image_eq_iUnion, mem_Ici, iUnion_ge_eq_iUnion_nat_add _ (k + 1)]
    exact iUnion_mono fun i => subset_closure

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

Goal state before:
pp: case refine_2
X : Type u_1
Y : Type u_2
inst✝² : TopologicalSpace X
inst✝¹ : TopologicalSpace Y
inst✝ : SecondCountableTopology Y
S : Set (Set X)
hScount : S.Countable
hScomp : ∀ K ∈ S, IsCompact K
hS : ∀ (f : C(X, Y)) (V : Set Y), IsOpen[inst✝¹] V → ∀ x ∈ ⇑f ⁻¹' V, ∃ K ∈ S, K ∈ 𝓝 x ∧ MapsTo (⇑f) K V
f : C(X, Y)
x : X
⊢ ∀ V ∈ countableBasis Y, f x ∈ V → ∃ K ∈ S, K ∈ 𝓝 x ∧ MapsTo (⇑f) K V

Tactic:
V

Goal state after:
case refine_2
X : Type u_1
Y : Type u_2
inst✝² : TopologicalSpace X
inst✝¹ : TopologicalSpace Y
inst✝ : SecondCountableTopology Y
S : Set (Set X)
hScount : S.Countable
hScomp : ∀ K ∈ S, IsCompact K
hS : ∀ (f : C(X, Y)) (V : Set Y), IsOpen[inst✝¹] V → ∀ x ∈ ⇑f ⁻¹' V, ∃ K ∈ S, K ∈ 𝓝 x ∧ MapsTo (⇑f) K V
f : C(X, Y)
x : X
V : Set Y
⊢ V ∈ countableBasis Y → f x ∈ V → ∃ K ∈ S, K ∈ 𝓝 x ∧ MapsTo (⇑f) K V
Module: Mathlib.Topology.ContinuousMap.SecondCountableSpace

Goal state before:
pp: case h.refine_2
X : Type u_1
Y : Type u_2
inst✝⁴ : TopologicalSpace X
inst✝³ : TopologicalSpace Y
inst✝² : SecondCountableTopology X
inst✝¹ : LocallyCompactSpace X
inst✝ : SecondCountableTopology Y
this : ∀ (U : ↑(countableBasis X)), LocallyCompactSpace ↑↑U
K : (U : ↑(countableBasis X)) → CompactExhaustion ↑↑U := fun U ↦ CompactExhaustion.choice ↑↑U
f : C(X, Y)
⊢ ∀ (V : Set Y),
    IsOpen[inst✝³] V → ∀ x ∈ ⇑f ⁻¹' V, ∃ K_1 ∈ ⋃ U, range fun n ↦ Subtype.val '' (K U) n, K_1 ∈ 𝓝 x ∧ MapsTo (⇑f) K_1 V

Tactic:
V

Goal state after:
case h.refine_2
X : Type u_1
Y : Type u_2
inst✝⁴ : TopologicalSpace X
inst✝³ : TopologicalSpace Y
inst✝² : SecondCountableTopology X
inst✝¹ : LocallyCompactSpace X
inst✝ : SecondCountableTopology Y
this : ∀ (U : ↑(countableBasis X)), LocallyCompactSpace ↑↑U
K : (U : ↑(countableBasis X)) → CompactExhaustion ↑↑U := fun U ↦ CompactExhaustion.choice ↑↑U
f : C(X, Y)
V : Set Y
⊢ IsOpen[inst✝³] V → ∀ x ∈ ⇑f ⁻¹' V, ∃ K_1 ∈ ⋃ U, range fun n ↦ Subtype.val '' (K U) n, K_1 ∈ 𝓝 x ∧ MapsTo (⇑f) K_1 V
Module: Mathlib.Topology.EMetricSpace.PairReduction

Goal state before:
pp: case pos
T : Type u_1
inst✝ : PseudoEMetricSpace T
a c : ℝ≥0∞
V : Finset T
t : T
ha : 1 < a
ht : t ∈ V
h_one : logSizeRadius t V a c = 1
⊢ a ^ (logSizeRadius t V a c - 1) ≤ ↑(#({x ∈ V | edist t x ≤ (↑(logSizeRadius t V a c) - 1) * c}))

Tactic:
simp only [h_one, tsub_self, pow_zero, Nat.cast_one, zero_mul, nonpos_iff_eq_zero,
      Nat.one_le_cast, Finset.one_le_card]
    exact ⟨t, by simpa⟩

Goal state after:
Module: Mathlib.Topology.Homotopy.HomotopyGroup

Goal state before:
pp: N : Type u_1
inst✝ : DecidableEq N
i : N
t₀ : ↑I
t : { j // j ≠ i } → ↑I
H : (t₀ = 0 ∨ t₀ = 1) ∨ t ∈ boundary { j // j ≠ i }
⊢ (insertAt i) (t₀, t) ∈ boundary N

Tactic:
by
  obtain H | ⟨j, H⟩ := H
  · use i; rwa [funSplitAt_symm_apply, dif_pos rfl]
  · use j; rwa [funSplitAt_symm_apply, dif_neg j.prop, Subtype.coe_eta]

Goal state after:
Module: Mathlib.Topology.IsClosedRestrict

Goal state before:
pp: ι : Type u_1
α✝ : ι → Type u_2
s✝ : Set ((i : ι) → α✝ i)
i : ι
S✝ : Set ι
α : ι → Type u_3
inst✝ : (i : ι) → TopologicalSpace (α i)
S : Set ι
s : Set ((j : ι) → α j)
⊢ Continuous[instTopologicalSpaceSubtype, instTopologicalSpaceProd] fun x ↦ (⟨Sᶜ.domRestrict ↑x, ⋯⟩, fun i ↦ ↑x ↑i)

Tactic:
refine (Continuous.subtype_mk (by fun_prop) _).prodMk ?_
    rw [continuous_pi_iff]
    exact fun _ ↦ (continuous_apply _).comp continuous_subtype_val

Goal state after:
Module: Mathlib.Topology.IsClosedRestrict

Goal state before:
pp: ι : Type u_1
α : ι → Type u_2
S : Set ι
inst✝¹ : (i : ι) → TopologicalSpace (α i)
inst✝ : ∀ (i : ι), CompactSpace (α i)
s : Set ((a : ι) → α a)
hs : IsClosed s
this : S.domRestrict = Prod.fst ∘ ⇑(Homeomorph.piEquivPiSubtypeProd (fun x ↦ x ∈ S) α)
⊢ IsClosed (S.domRestrict '' s)

Tactic:
rw [this, image_comp]

Goal state after:
ι : Type u_1
α : ι → Type u_2
S : Set ι
inst✝¹ : (i : ι) → TopologicalSpace (α i)
inst✝ : ∀ (i : ι), CompactSpace (α i)
s : Set ((a : ι) → α a)
hs : IsClosed s
this : S.domRestrict = Prod.fst ∘ ⇑(Homeomorph.piEquivPiSubtypeProd (fun x ↦ x ∈ S) α)
⊢ IsClosed (Prod.fst '' ⇑(Homeomorph.piEquivPiSubtypeProd (fun x ↦ x ∈ S) α) '' s)
Module: Mathlib.Topology.MetricSpace.GromovHausdorffRealized

Goal state before:
pp: X : Type u
Y : Type v
inst✝¹ : MetricSpace X
inst✝ : MetricSpace Y
f : ProdSpaceFun X Y
fA : f ∈ candidates X Y
⊢ LipschitzWith (2 * maxVar X Y) f

Tactic:
by
  apply LipschitzWith.of_dist_le_mul
  rintro ⟨x, y⟩ ⟨z, t⟩
  rw [Real.dist_eq, abs_sub_le_iff]
  use candidates_lipschitz_aux fA
  rw [dist_comm]
  exact candidates_lipschitz_aux fA

Goal state after:
Module: Mathlib.Topology.MetricSpace.CoveringNumbers

Goal state before:
pp: case refine_2
X : Type u_1
inst✝ : PseudoEMetricSpace X
A : Set X
ε : ℝ≥0
C' : Set X
hC'_subset : C' ⊆ A
hC'_cover : IsCover ε A C'
hC'_fin : C'.Finite
this : Nonempty { s // s ⊆ A ∧ IsCover ε A s }
C : { s // s ⊆ A ∧ IsCover ε A s }
hC : (↑C).encard = ⨅ x, (↑x).encard
⊢ ⨅ x, (↑x).encard = coveringNumber ε A

Tactic:
iInf_subtype,

Goal state after:
case refine_2
X : Type u_1
inst✝ : PseudoEMetricSpace X
A : Set X
ε : ℝ≥0
C' : Set X
hC'_subset : C' ⊆ A
hC'_cover : IsCover ε A C'
hC'_fin : C'.Finite
this : Nonempty { s // s ⊆ A ∧ IsCover ε A s }
C : { s // s ⊆ A ∧ IsCover ε A s }
hC : (↑C).encard = ⨅ x, (↑x).encard
⊢ ⨅ i, ⨅ (_ : i ⊆ A ∧ IsCover ε A i), i.encard = coveringNumber ε A
Module: Mathlib.Topology.MetricSpace.HolderNorm

Goal state before:
pp: X : Type u_1
Y : Type u_2
inst✝¹ : PseudoEMetricSpace X
inst✝ : PseudoEMetricSpace Y
r : ℝ≥0
f : X → Y
s t : ℝ≥0
A : Set X
hf₂ : ∃ C, HolderOnWith C t f A
hrs : r ≤ s
hst : s ≤ t
C₁ : ℝ≥0
hf₁ : HolderOnWith C₁ r f A
⊢ ∃ C, HolderOnWith C s f A

Tactic:
obtain ⟨C₂, hf₂⟩ := hf₂

Goal state after:
X : Type u_1
Y : Type u_2
inst✝¹ : PseudoEMetricSpace X
inst✝ : PseudoEMetricSpace Y
r : ℝ≥0
f : X → Y
s t : ℝ≥0
A : Set X
hrs : r ≤ s
hst : s ≤ t
C₁ : ℝ≥0
hf₁ : HolderOnWith C₁ r f A
C₂ : ℝ≥0
hf₂ : HolderOnWith C₂ t f A
⊢ ∃ C, HolderOnWith C s f A
Module: Mathlib.Topology.MetricSpace.HolderNorm

Goal state before:
pp: case mpr.inl
X : Type u_1
Y : Type u_2
inst✝¹ : MetricSpace X
inst✝ : EMetricSpace Y
r : ℝ≥0
f : X → Y
h : ∀ (x₁ x₂ : X), f x₁ = f x₂
hX : IsEmpty X
⊢ eHolderNorm r f = 0

Tactic:
exact eHolderNorm_of_isEmpty

Goal state after:
Module: Mathlib.Topology.MetricSpace.HolderNorm

Goal state before:
pp: X : Type u_1
Y : Type u_2
inst✝¹ : MetricSpace X
inst✝ : EMetricSpace Y
r : ℝ≥0
f : X → Y
hf : MemHolder r f
⊢ eHolderNorm r f ≠ ∞

Tactic:
exact ne_of_lt <| lt_of_le_of_lt hf.holderWith.eHolderNorm_le <| coe_lt_top

Goal state after:
Module: Mathlib.Topology.NatEmbedding

Goal state before:
pp: case pos
X : Type u_1
inst✝² : TopologicalSpace X
inst✝¹ : T2Space X
inst✝ : Infinite X
h : DiscreteTopology X
⊢ ∃ U, (∀ (n : ℕ), (U n).Nonempty) ∧ (∀ (n : ℕ), IsOpen[inst✝²] (U n)) ∧ Pairwise (Disjoint on U)

Tactic:
refine ⟨fun n ↦ {Infinite.natEmbedding X n}, fun _ ↦ singleton_nonempty _,
      fun _ ↦ isOpen_discrete _, fun _ _ h ↦ ?_⟩

Goal state after:
case pos
X : Type u_1
inst✝² : TopologicalSpace X
inst✝¹ : T2Space X
inst✝ : Infinite X
h✝ : DiscreteTopology X
x✝¹ x✝ : ℕ
h : x✝¹ ≠ x✝
⊢ (Disjoint on fun n ↦ {(Infinite.natEmbedding X) n}) x✝¹ x✝
Module: Mathlib.Topology.Order.UpperLowerSetTopology

Goal state before:
pp: case mpr
α : Type u_1
β : Type u_2
inst✝⁵ : Preorder α
inst✝⁴ : Preorder β
inst✝³ : TopologicalSpace α
inst✝² : TopologicalSpace β
inst✝¹ : Topology.IsUpperSet α
inst✝ : Topology.IsUpperSet β
f : α → β
hf : Continuous[inst✝³, inst✝²] f
a : α
⊢ ∀ ⦃b : α⦄, a ≤ b → f a ≤ f b

Tactic:
b

Goal state after:
case mpr
α : Type u_1
β : Type u_2
inst✝⁵ : Preorder α
inst✝⁴ : Preorder β
inst✝³ : TopologicalSpace α
inst✝² : TopologicalSpace β
inst✝¹ : Topology.IsUpperSet α
inst✝ : Topology.IsUpperSet β
f : α → β
hf : Continuous[inst✝³, inst✝²] f
a b : α
⊢ a ≤ b → f a ≤ f b
Module: Mathlib.Topology.MetricSpace.GromovHausdorff

Goal state before:
pp: X : Type u
inst✝ : MetricSpace X
p q : NonemptyCompacts X
⊢ dist p.toGHSpace q.toGHSpace ≤ dist p q

Tactic:
have ha : Isometry ((↑) : p → X) := isometry_subtype_coe
  have hb : Isometry ((↑) : q → X) := isometry_subtype_coe
  have A : dist p q = hausdorffDist (p : Set X) q := rfl
  have I : ↑p = range ((↑) : p → X) := Subtype.range_coe_subtype.symm
  have J : ↑q = range ((↑) : q → X) := Subtype.range_coe_subtype.symm
  rw [A, I, J]
  exact ghDist_le_hausdorffDist ha hb

Goal state after:
Module: Mathlib.Topology.Sheaves.PUnit

Goal state before:
pp: case inl
C : Type u
inst✝ : Category.{v, u} C
X : TopCat
hind : X.str = ⊤
F : Presheaf C X
it : IsTerminal (F.obj (op ⊥))
c : C
this : IndiscreteTopology ↑X
s : Sieve ⊥
hs : s ∈ (Opens.grothendieckTopology ↑X) ⊥
⊢ Presieve.IsSheafFor (F ⋙ coyoneda.obj (op c)) s.arrows

Tactic:
intro _ _
    rw [@existsUnique_iff_exists _ ⟨fun _ _ => _⟩]
    · refine ⟨it.from _, fun U hU hs => IsTerminal.hom_ext ?_ _ _⟩
      rwa [le_bot_iff.1 hU.le]
    · apply it.hom_ext

Goal state after:
Module: Mathlib.Topology.Separation.PerfectlyNormal

Goal state before:
pp: X : Type u_1
inst✝ : TopologicalSpace X
h : PerfectlyNormalSpace X
s : Set X
hs : IsClosed[inst✝] s
⊢ ∃ f, s = ⇑f ⁻¹' {0} ∧ ∀ (x : X), f x ∈ Icc 0 1

Tactic:
by
    -- write `s` as the intersection of a sequence of open sets `U n`
    obtain ⟨U, ho, hu⟩ := isGδ_iff_eq_iInter_nat.1 hs.isGδ
    have (n : ℕ) : Disjoint s (U n)ᶜ := by
      apply LE.le.disjoint_compl_right
      grw [hu, iInter_subset]
    -- for each `n`, construct a continuous function `f n` that separates `s` from `(U n)ᶜ`
    choose f hfs hfu hfr using fun n =>
      exists_continuous_zero_one_of_isClosed hs (ho n).isClosed_compl (this n)
    have hsb (x : X) (n : ℕ) : ‖(f n) x * (1 / 2 / 2 ^ n)‖ ≤ 1 / 2 / 2 ^ n := by
      simp [abs_of_nonneg (hfr n x).1, (hfr n x).2]
    have hsx (x : X) : Summable fun n => f n x * (1 / 2 / 2 ^ n) :=
      (summable_geometric_two' 1).of_norm_bounded fun n => hsb x n
    -- consider the infinite sum of `f n x * (1 / 2 / 2 ^ n)`, which is uniformly convergent and
    -- thus continuous because it is dominated by a geometric series
    let h : C(X, ℝ) :=
      { toFun x := ∑' n, f n x * (1 / 2 / 2 ^ n)
        continuous_toFun :=
          continuous_tsum (fun n => by fun_prop) (summable_geometric_two' 1) fun n x => hsb x n }
    refine ⟨h, ?_, fun x => ⟨?_, ?_⟩⟩
    · ext x
      refine ⟨fun hp => ?_, fun hp => ?_⟩
      · suffices ∀ n, f n x = 0 from by simp [h, this]
        exact fun n => hfs n hp
      · contrapose h
        simp only [preimage, notMem_ofPred_iff, ContinuousMap.coe_mk, mem_singleton_iff]
        apply ne_of_gt
        obtain ⟨i, hi⟩ := mem_iUnion.1 <| compl_iInter _ ▸ mem_compl (hu ▸ h)
        calc
        _ < 1 / 2 / 2 ^ i := by positivity
        _ = f i x * (1 / 2 / 2 ^ i) := by simp [hfu i hi]
        _ ≤ _ := (hsx x).le_tsum i fun j hj => by positivity [(hfr j x).1]
    · exact tsum_nonneg fun n => by simp [(hfr n x).1]
    · calc
      _ = ∑' n, f n x * (1 / 2 / 2 ^ n) := by simp [h]
      _ ≤ ∑' n, 1 / 2 / 2 ^ n :=
        (hsx x).tsum_le_tsum (fun n => by simp [(hfr n x).2]) (summable_geometric_two' 1)
      _ = _ := tsum_geometric_two' 1

Goal state after: