mathlib-initiative/mathlib-tactics huggingface dataset:
Module: Mathlib.Topology.Category.Profinite.Nobeling.Successor

Goal state before:
pp: I : Type u
inst✝² : LinearOrder I
inst✝¹ : WellFoundedLT I
o : Ordinal.{u}
ho : o < Ordinal.type fun x1 x2 ↦ x1 < x2
inst✝ : Inhabited I
l : Products I
hl : ↑l ≠ []
hlh : (↑l).head! = term I ho
⊢ (↑l).head! :: (↑l).tail = term I ho :: ↑l.Tail

Tactic:
hlh

Goal state after:
I : Type u
inst✝² : LinearOrder I
inst✝¹ : WellFoundedLT I
o : Ordinal.{u}
ho : o < Ordinal.type fun x1 x2 ↦ x1 < x2
inst✝ : Inhabited I
l : Products I
hl : ↑l ≠ []
hlh : (↑l).head! = term I ho
⊢ term I ho :: (↑l).tail = term I ho :: ↑l.Tail
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
j : cell C n
⊢ Disjoint (interior D) (closedCell n j)

Tactic:
rw [disjoint_iff_inter_eq_empty]

Goal state after:
X : Type u_1
t : TopologicalSpace X
C D : Set X
inst✝¹ : T2Space X
inst✝ : RelCWComplex C D
n : ℕ
j : cell C n
⊢ interior D ∩ closedCell n j = ∅
Module: Mathlib.Topology.Compactness.CompactSystem

Goal state before:
pp: α : Type u_1
S : Set (Set α)
hpi : IsPiSystem S
h : ∀ (C : ℕ → Set α), Directed (fun x1 x2 ↦ x1 ⊇ x2) C → (∀ (i : ℕ), C i ∈ S) → ⋂ i, C i = ∅ → ∃ n, C n = ∅
C : ℕ → Set α
h1 : ∀ (i : ℕ), C i ∈ insert ∅ S
h2 : ⋂ n, ⋂ m, ⋂ (_ : m ≤ n), C m = ∅
this : (∀ (n : ℕ), dissipate C n ∈ S ∨ dissipate C n = ∅) ∧ ⋂ n, dissipate C n = ∅
⊢ ∃ n, dissipate C n = ∅

Tactic:
by_cases! f : ∀ n, dissipate C n ∈ S

Goal state after:
case pos
α : Type u_1
S : Set (Set α)
hpi : IsPiSystem S
h : ∀ (C : ℕ → Set α), Directed (fun x1 x2 ↦ x1 ⊇ x2) C → (∀ (i : ℕ), C i ∈ S) → ⋂ i, C i = ∅ → ∃ n, C n = ∅
C : ℕ → Set α
h1 : ∀ (i : ℕ), C i ∈ insert ∅ S
h2 : ⋂ n, ⋂ m, ⋂ (_ : m ≤ n), C m = ∅
this : (∀ (n : ℕ), dissipate C n ∈ S ∨ dissipate C n = ∅) ∧ ⋂ n, dissipate C n = ∅
f : ∀ (n : ℕ), dissipate C n ∈ S
⊢ ∃ n, dissipate C n = ∅

case neg
α : Type u_1
S : Set (Set α)
hpi : IsPiSystem S
h : ∀ (C : ℕ → Set α), Directed (fun x1 x2 ↦ x1 ⊇ x2) C → (∀ (i : ℕ), C i ∈ S) → ⋂ i, C i = ∅ → ∃ n, C n = ∅
C : ℕ → Set α
h1 : ∀ (i : ℕ), C i ∈ insert ∅ S
h2 : ⋂ n, ⋂ m, ⋂ (_ : m ≤ n), C m = ∅
this : (∀ (n : ℕ), dissipate C n ∈ S ∨ dissipate C n = ∅) ∧ ⋂ n, dissipate C n = ∅
f : ∃ n, dissipate C n ∉ S
⊢ ∃ n, dissipate C n = ∅
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}
hC : IsClosed C
hsC : contained C (Order.succ o)
ho : o < Ordinal.type fun x1 x2 ↦ x1 < x2
l : ↑(MaxProducts C ho)
h₁ : ⊤ ≤ Submodule.span ℤ (Set.range (eval (π C fun x ↦ ord I x < o)))
this : Inhabited I
m : Products I →₀ ℤ
hmmem : m ∈ Finsupp.supported ℤ ℤ {m | m < (↑l).Tail}
hmsum : (m.sum fun i a ↦ a • Products.eval (C' C ho) i) = (Linear_CC' C hsC ho) (Products.eval C ↑l)
hse : (πs C o).range = (Linear_CC' C hsC ho).ker
n : LocallyConstant ↑(π C fun x ↦ ord I x < o) ℤ
w : { l // Products.isGood (π C fun x ↦ ord I x < o) l } →₀ ℤ
hn :
  ((πs C o) (w.sum fun i a ↦ a • eval (π C fun x ↦ ord I x < o) i) +
      m.sum fun i a ↦ a • (List.map (e C) (term I ho :: ↑i)).prod) =
    Products.eval C ↑l
hc : (w.sum fun i a ↦ a • eval (π C fun x ↦ ord I x < o) i) = n
⊢ False

Tactic:
map_finsuppSum

Goal state after:
I : Type u
C : Set (I → Bool)
inst✝¹ : LinearOrder I
inst✝ : WellFoundedLT I
o : Ordinal.{u}
hC : IsClosed C
hsC : contained C (Order.succ o)
ho : o < Ordinal.type fun x1 x2 ↦ x1 < x2
l : ↑(MaxProducts C ho)
h₁ : ⊤ ≤ Submodule.span ℤ (Set.range (eval (π C fun x ↦ ord I x < o)))
this : Inhabited I
m : Products I →₀ ℤ
hmmem : m ∈ Finsupp.supported ℤ ℤ {m | m < (↑l).Tail}
hmsum : (m.sum fun i a ↦ a • Products.eval (C' C ho) i) = (Linear_CC' C hsC ho) (Products.eval C ↑l)
hse : (πs C o).range = (Linear_CC' C hsC ho).ker
n : LocallyConstant ↑(π C fun x ↦ ord I x < o) ℤ
w : { l // Products.isGood (π C fun x ↦ ord I x < o) l } →₀ ℤ
hn :
  ((w.sum fun a b ↦ (πs C o) (b • eval (π C fun x ↦ ord I x < o) a)) +
      m.sum fun i a ↦ a • (List.map (e C) (term I ho :: ↑i)).prod) =
    Products.eval C ↑l
hc : (w.sum fun i a ↦ a • eval (π C fun x ↦ ord I x < o) i) = n
⊢ False
Module: Mathlib.Topology.Compactness.CountablyCompact

Goal state before:
pp: ι : Type u_1
E : Type u_2
inst✝ : TopologicalSpace E
A : Set E
hA : IsCountablyCompact A
b : Set ι
hb : b.Countable
U : ι → Set E
hUo : ∀ i ∈ b, IsOpen[inst✝] (U i)
hAU : A ⊆ ⋃ i ∈ b, U i
⊢ ∃ t ⊆ b, t.Finite ∧ A ⊆ ⋃ i ∈ t, U i

Tactic:
by
  have := hb.to_subtype
  obtain ⟨t, ht⟩ := hA.elim_finite_subcover (fun (i : b) ↦ hUo i i.prop) (by simpa using hAU)
  simp only [Subtype.forall', biUnion_eq_iUnion] at hUo hAU
  replace hb := hb.to_subtype
  obtain ⟨d, hd⟩ := hA.elim_finite_subcover hUo hAU
  refine ⟨Subtype.val '' (d : Set b), ?_, d.finite_toSet.image _, ?_⟩
  · simp
  · rwa [biUnion_image]

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

Goal state before:
pp: case prop'
X : Type u
Y : Type v
inst✝³ : TopologicalSpace X
inst✝² : TopologicalSpace Y
inst✝¹ : HSpace X
inst✝ : HSpace Y
G : ↑I × X × Y → X × Y := ⋯
hG : Continuous G
⊢ ∀ (t : ↑I),
    ∀ x ∈ {(e, e)},
      { toFun := fun x ↦ { toFun := G, continuous_toFun := hG, map_zero_left := ⋯, map_one_left := ⋯ }.toFun (t, x),
            continuous_toFun := ⋯ }
          x =
        ({ toFun := fun p ↦ (hmul (p.1.1, p.2.1), hmul (p.1.2, p.2.2)), continuous_toFun := ⋯ }.comp
            ((const (X × Y) (e, e)).prodMk (ContinuousMap.id (X × Y))))
          x

Tactic:
· rintro t ⟨x, y⟩ h
      replace h := Prod.mk_inj.mp h
      exact Prod.ext (HSpace.eHmul.2 t x h.1) (HSpace.eHmul.2 t y h.2)

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

Goal state before:
pp: X : Type u
inst✝ : TopologicalSpace X
x y : X
γ : Path x y
⊢ delayReflRight 0 γ = γ.trans (refl y)

Tactic:
ext t

Goal state after:
X : Type u
inst✝ : TopologicalSpace X
x y : X
γ : Path x y
t : ↑I
⊢ (delayReflRight 0 γ) t = (γ.trans (refl y)) t
Module: Mathlib.Topology.Homotopy.HSpaces

Goal state before:
pp: X : Type u
inst✝ : TopologicalSpace X
x y : X
γ : Path x y
⊢ delayReflRight 1 γ = γ

Tactic:
ext t

Goal state after:
X : Type u
inst✝ : TopologicalSpace X
x y : X
γ : Path x y
t : ↑I
⊢ (delayReflRight 1 γ) t = γ t
Module: Mathlib.Topology.Homotopy.HomotopyGroup

Goal state before:
pp: N : Type u_1
X : Type u_2
inst✝ : TopologicalSpace X
x✝ : X
M : Type ?u.15
x : X
e : M ≃ N
p : ↑(Ω^ M X x)
⊢ (fun p ↦ ⟨(↑p).comp { toFun := fun t n ↦ t (e.symm n), continuous_toFun := ⋯ }, ⋯⟩)
      ((fun p ↦ ⟨(↑p).comp { toFun := fun t m ↦ t (e m), continuous_toFun := ⋯ }, ⋯⟩) p) =
    p

Tactic:
ext t

Goal state after:
N : Type u_1
X : Type u_2
inst✝ : TopologicalSpace X
x✝ : X
M : Type ?u.15
x : X
e : M ≃ N
p : ↑(Ω^ M X x)
t : M → ↑I
⊢ ((fun p ↦ ⟨(↑p).comp { toFun := fun t n ↦ t (e.symm n), continuous_toFun := ⋯ }, ⋯⟩)
        ((fun p ↦ ⟨(↑p).comp { toFun := fun t m ↦ t (e m), continuous_toFun := ⋯ }, ⋯⟩) p))
      t =
    p t
Module: Mathlib.Topology.Homotopy.HomotopyGroup

Goal state before:
pp: N : Type u_1
X : Type u_2
inst✝ : TopologicalSpace X
x✝ : X
M : Type ?u.15
x : X
e : M ≃ N
p : ↑(Ω^ N X x)
⊢ (fun p ↦ ⟨(↑p).comp { toFun := fun t m ↦ t (e m), continuous_toFun := ⋯ }, ⋯⟩)
      ((fun p ↦ ⟨(↑p).comp { toFun := fun t n ↦ t (e.symm n), continuous_toFun := ⋯ }, ⋯⟩) p) =
    p

Tactic:
ext t

Goal state after:
N : Type u_1
X : Type u_2
inst✝ : TopologicalSpace X
x✝ : X
M : Type ?u.15
x : X
e : M ≃ N
p : ↑(Ω^ N X x)
t : N → ↑I
⊢ ((fun p ↦ ⟨(↑p).comp { toFun := fun t m ↦ t (e m), continuous_toFun := ⋯ }, ⋯⟩)
        ((fun p ↦ ⟨(↑p).comp { toFun := fun t n ↦ t (e.symm n), continuous_toFun := ⋯ }, ⋯⟩) p))
      t =
    p t
Module: Mathlib.Topology.Homotopy.HomotopyGroup

Goal state before:
pp: N : Type u_1
X : Type u_2
inst✝¹ : TopologicalSpace X
x : X
inst✝ : DecidableEq N
i : N
p : ↑(Ω^ N X x)
⊢ ⟨((↑p).comp ↑(Cube.insertAt i)).curry 0, ⋯⟩ = const

Tactic:
ext t

Goal state after:
N : Type u_1
X : Type u_2
inst✝¹ : TopologicalSpace X
x : X
inst✝ : DecidableEq N
i : N
p : ↑(Ω^ N X x)
t : { j // j ≠ i } → ↑I
⊢ ⟨((↑p).comp ↑(Cube.insertAt i)).curry 0, ⋯⟩ t = const t
Module: Mathlib.Topology.Homotopy.HomotopyGroup

Goal state before:
pp: N : Type u_1
X : Type u_2
inst✝¹ : TopologicalSpace X
x : X
inst✝ : DecidableEq N
i : N
p : ↑(Ω^ N X x)
⊢ ⟨((↑p).comp ↑(Cube.insertAt i)).curry 1, ⋯⟩ = const

Tactic:
ext t

Goal state after:
N : Type u_1
X : Type u_2
inst✝¹ : TopologicalSpace X
x : X
inst✝ : DecidableEq N
i : N
p : ↑(Ω^ N X x)
t : { j // j ≠ i } → ↑I
⊢ ⟨((↑p).comp ↑(Cube.insertAt i)).curry 1, ⋯⟩ t = const t
Module: Mathlib.Topology.EMetricSpace.PairReduction

Goal state before:
pp: T✝ : Type u_1
inst✝³ : PseudoEMetricSpace T✝
a✝ c✝ : ℝ≥0∞
n✝ : ℕ
J✝ : Finset T✝
inst✝² : DecidableEq T✝
T : Type u_1
inst✝¹ : PseudoEMetricSpace T
a c : ℝ≥0∞
n : ℕ
J : Finset T
inst✝ : DecidableEq T
ha : 1 < a
hJ_card : ↑(#J) ≤ a ^ n
t : T
i : ℕ
hiJ : i < #J
hJ : J.Nonempty
hn : 1 ≤ n
ht : t ∈ (logSizeBallSeq J ⋯ a c i).finset
hdist : edist (logSizeBallSeq J ⋯ a c i).point t ≤ ↑(logSizeBallSeq J ⋯ a c i).radius * c
h : ((logSizeBallSeq J ⋯ a c i).point, t) ∈ pairSet J a c
⊢ ↑(logSizeBallSeq J ⋯ a c i).radius * c ≤ ↑n * c

Tactic:
radius_logSizeBallSeq_le hJ ha hn hJ_card i

Goal state after:
T✝ : Type u_1
inst✝³ : PseudoEMetricSpace T✝
a✝ c✝ : ℝ≥0∞
n✝ : ℕ
J✝ : Finset T✝
inst✝² : DecidableEq T✝
T : Type u_1
inst✝¹ : PseudoEMetricSpace T
a c : ℝ≥0∞
n : ℕ
J : Finset T
inst✝ : DecidableEq T
ha : 1 < a
hJ_card : ↑(#J) ≤ a ^ n
t : T
i : ℕ
hiJ : i < #J
hJ : J.Nonempty
hn : 1 ≤ n
ht : t ∈ (logSizeBallSeq J ⋯ a c i).finset
hdist : edist (logSizeBallSeq J ⋯ a c i).point t ≤ ↑(logSizeBallSeq J ⋯ a c i).radius * c
h : ((logSizeBallSeq J ⋯ a c i).point, t) ∈ pairSet J a c
⊢ ↑n * c ≤ ↑n * c
Module: Mathlib.Topology.Instances.CantorSet

Goal state before:
pp: case succ.right
n : ℕ
ih : 1 / 4 ∈ preCantorSet n ∧ 3 / 4 ∈ preCantorSet n
⊢ 3 / 4 ∈ preCantorSet (n + 1)

Tactic:
exact Or.inr ⟨1 / 4, ih.1, by norm_num⟩

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

Goal state before:
pp: X : Type u_2
inst✝² : TopologicalSpace X
x : X
N : Type u_3
inst✝¹ : DecidableEq N
inst✝ : Unique N
p q : ↑(Ω^ N X x)
⊢ (genLoopEquivOfUnique N) (transAt default q p) = Path.trans ((genLoopEquivOfUnique N) q) ((genLoopEquivOfUnique N) p)

Tactic:
ext t

Goal state after:
X : Type u_2
inst✝² : TopologicalSpace X
x : X
N : Type u_3
inst✝¹ : DecidableEq N
inst✝ : Unique N
p q : ↑(Ω^ N X x)
t : ↑I
⊢ ((genLoopEquivOfUnique N) (transAt default q p)) t =
    (Path.trans ((genLoopEquivOfUnique N) q) ((genLoopEquivOfUnique N) p)) t
Module: Mathlib.Topology.MetricSpace.CoveringNumbers

Goal state before:
pp: E : Type u_3
inst✝ : EMetricSpace E
A : Set E
⊢ externalCoveringNumber 0 A = A.encard

Tactic:
by
  refine le_antisymm (externalCoveringNumber_le_encard_self A) ?_
  refine le_iInf fun C ↦ le_iInf fun hC₁ ↦ ?_
  rw [isCover_zero] at hC₁
  exact encard_le_encard hC₁

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

Goal state before:
pp: case inr
X : Type u_1
inst✝ : PseudoEMetricSpace X
ε : ℝ≥0
A : Set X
h_nonempty : A.Nonempty
⊢ packingNumber (2 * ε) A ≤ externalCoveringNumber ε A

Tactic:
exact packingNumber_two_mul_le_externalCoveringNumber ε A

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

Goal state before:
pp: Y : Type u_2
inst✝¹ : PseudoEMetricSpace Y
r : ℝ≥0
X : Type u_3
inst✝ : PseudoMetricSpace X
hX : BoundedSpace X
f : X → Y
s : ℝ≥0
hf : MemHolder r f
hs : s ≤ r
⊢ MemHolder s f

Tactic:
obtain ⟨C, hf⟩ := hf
  obtain ⟨C', hC'⟩ := Metric.boundedSpace_iff_edist.1 hX
  exact ⟨C * C' ^ (r - s : ℝ),
    holderOnWith_univ.1 <| (holderOnWith_univ.2 hf).of_le (fun x _ y _ ↦ hC' x y) hs⟩

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

Goal state before:
pp: case neg
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
x₁ x₂ : X
hx : ¬x₁ = x₂
⊢ edist (f x₁) (f x₂) ≤ ↑(nnHolderNorm r f) * edist x₁ x₂ ^ ↑r

Tactic:
nnHolderNorm,

Goal state after:
case neg
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
x₁ x₂ : X
hx : ¬x₁ = x₂
⊢ edist (f x₁) (f x₂) ≤ ↑(eHolderNorm r f).toNNReal * edist x₁ x₂ ^ ↑r
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
⊢ ↑(nnHolderNorm r f) = eHolderNorm r f

Tactic:
nnHolderNorm,

Goal state after:
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).toNNReal = eHolderNorm r f
Module: Mathlib.Topology.Order.PartialSups

Goal state before:
pp: L : Type u_1
inst✝² : SemilatticeSup L
inst✝¹ : TopologicalSpace L
inst✝ : ContinuousSup L
α : Type u_2
l : Filter α
f : ℕ → α → L
g : ℕ → L
n : ℕ
hf : ∀ k ≤ n, Tendsto (f k) l (𝓝 (g k))
⊢ Tendsto ((partialSups f) n) l (𝓝 ((partialSups g) n))

Tactic:
simp only [partialSups_eq_sup'_range]
  refine finset_sup'_nhds _ ?_
  simpa [Nat.lt_succ_iff]

Goal state after:
Module: Mathlib.Topology.Order.LawsonTopology

Goal state before:
pp: α : Type u_1
inst✝² : Preorder α
inst✝¹ : TopologicalSpace α
inst✝ : IsLawson α
⊢ {s | ∃ t, t.Finite ∧ ∃ u, IsOpen[scott α univ] u ∧ u \ ↑(upperClosure t) = s} =
    {c |
      ∃ a ∈ {s | ∃ t, t.Finite ∧ (↑(upperClosure t))ᶜ = s},
        ∃ b ∈ {U | IsOpen[scott α univ] U}, ⇑WithLower.toLower ⁻¹' a ∩ ⇑WithScott.toScott ⁻¹' b = c}

Tactic:
sdiff_eq_compl_inter

Goal state after:
α : Type u_1
inst✝² : Preorder α
inst✝¹ : TopologicalSpace α
inst✝ : IsLawson α
⊢ {s | ∃ t, t.Finite ∧ ∃ u, IsOpen[scott α univ] u ∧ (↑(upperClosure t))ᶜ ∩ u = s} =
    {c |
      ∃ a ∈ {s | ∃ t, t.Finite ∧ (↑(upperClosure t))ᶜ = s},
        ∃ b ∈ {U | IsOpen[scott α univ] U}, ⇑WithLower.toLower ⁻¹' a ∩ ⇑WithScott.toScott ⁻¹' b = c}
Module: Mathlib.Topology.Separation.PerfectlyNormal

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

Tactic:
by_cases! hse : s = ∅

Goal state after:
case pos
X : Type u_1
inst✝ : TopologicalSpace X
h : ∀ (s : Set X), IsClosed[inst✝] s → ∃ f, s = ⇑f ⁻¹' {0} ∧ ∀ (x : X), f x ∈ Icc 0 1
s : Set X
hs : IsClosed[inst✝] s
hse : s = ∅
⊢ IsGδ s

case neg
X : Type u_1
inst✝ : TopologicalSpace X
h : ∀ (s : Set X), IsClosed[inst✝] s → ∃ f, s = ⇑f ⁻¹' {0} ∧ ∀ (x : X), f x ∈ Icc 0 1
s : Set X
hs : IsClosed[inst✝] s
hse : s.Nonempty
⊢ IsGδ s
Module: Mathlib.Topology.Sheaves.Skyscraper

Goal state before:
pp: case neg
X : TopCat
p₀ : ↑X
inst✝² : (U : Opens ↑X) → Decidable (p₀ ∈ U)
C : Type v
inst✝¹ : Category.{w, v} C
inst✝ : HasTerminal C
A a b : C
f : a ⟶ b
U V : (Opens ↑X)ᵒᵖ
i : U ⟶ V
hV : p₀ ∉ unop V
⊢ ((if h : p₀ ∈ unop V then eqToHom ⋯ else (⋯ ▸ terminalIsTerminal).from (if p₀ ∈ unop U then a else ⊤_ C)) ≫
      if h : p₀ ∈ unop V then eqToHom ⋯ ≫ f ≫ eqToHom ⋯
      else (⋯ ▸ terminalIsTerminal).from ((skyscraperPresheaf p₀ a).obj V)) =
    (if h : p₀ ∈ unop U then eqToHom ⋯ ≫ f ≫ eqToHom ⋯
      else (⋯ ▸ terminalIsTerminal).from ((skyscraperPresheaf p₀ a).obj U)) ≫
      if h : p₀ ∈ unop V then eqToHom ⋯ else (⋯ ▸ terminalIsTerminal).from (if p₀ ∈ unop U then b else ⊤_ C)

Tactic:
apply ((if_neg hV).symm.ndrec terminalIsTerminal).hom_ext

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

Goal state before:
pp: X✝ : Type v
inst✝⁶ : TopologicalSpace X✝
inst✝⁵ : Preorder X✝
inst✝⁴ : Topology.IsUpperSet X✝
C : Type u
inst✝³ : Category.{v, u} C
inst✝² : HasLimits C
F✝ : X✝ ⥤ C
X : TopCat
inst✝¹ : Preorder ↑X
inst✝ : Topology.IsUpperSet ↑X
F : ↑X ⥤ C
α : Type v
Us : α → Opens ↑X
S : Cone ((ObjectProperty.ι fun V ↦ ∃ i, V ≤ Us i).op ⋙ principalsKanExtension F)
V : Opens ↑X
i : α
hV : V ≤ Us i
⊢ limit.lift (generator (iSup Us) ⋙ F) (lowerCone Us S) ≫
      limit.lift (StructuredArrow.proj (Opposite.op V) (principals ↑X) ⋙ F)
        { pt := limit (StructuredArrow.proj (Opposite.op (iSup Us)) (principals ↑X) ⋙ F),
          π :=
            {
              app := fun g ↦
                limit.π (StructuredArrow.proj (Opposite.op (iSup Us)) (principals ↑X) ⋙ F)
                  ((StructuredArrow.map
                        ((Opens.leSupr Us (OpensLeCover.index { obj := V, property := ⋯ })).op ≫
                          (OpensLeCover.homToIndex { obj := V, property := ⋯ }).op)).obj
                    g),
              naturality := ⋯ } } =
    S.π.app (Opposite.op { obj := V, property := ⋯ })

Tactic:
ext ⟨_, x, f⟩

Goal state after:
X✝ : Type v
inst✝⁶ : TopologicalSpace X✝
inst✝⁵ : Preorder X✝
inst✝⁴ : Topology.IsUpperSet X✝
C : Type u
inst✝³ : Category.{v, u} C
inst✝² : HasLimits C
F✝ : X✝ ⥤ C
X : TopCat
inst✝¹ : Preorder ↑X
inst✝ : Topology.IsUpperSet ↑X
F : ↑X ⥤ C
α : Type v
Us : α → Opens ↑X
S : Cone ((ObjectProperty.ι fun V ↦ ∃ i, V ≤ Us i).op ⋙ principalsKanExtension F)
V : Opens ↑X
i : α
hV : V ≤ Us i
left✝ : Discrete PUnit.{1}
x : ↑X
f : (fromPUnit (Opposite.op V)).obj left✝ ⟶ (principals ↑X).obj x
⊢ (limit.lift (generator (iSup Us) ⋙ F) (lowerCone Us S) ≫
        limit.lift (StructuredArrow.proj (Opposite.op V) (principals ↑X) ⋙ F)
          { pt := limit (StructuredArrow.proj (Opposite.op (iSup Us)) (principals ↑X) ⋙ F),
            π :=
              {
                app := fun g ↦
                  limit.π (StructuredArrow.proj (Opposite.op (iSup Us)) (principals ↑X) ⋙ F)
                    ((StructuredArrow.map
                          ((Opens.leSupr Us (OpensLeCover.index { obj := V, property := ⋯ })).op ≫
                            (OpensLeCover.homToIndex { obj := V, property := ⋯ }).op)).obj
                      g),
                naturality := ⋯ } }) ≫
      limit.π (StructuredArrow.proj (Opposite.op V) (principals ↑X) ⋙ F) { left := left✝, right := x, hom := f } =
    S.π.app (Opposite.op { obj := V, property := ⋯ }) ≫
      limit.π (StructuredArrow.proj (Opposite.op V) (principals ↑X) ⋙ F) { left := left✝, right := x, hom := f }
Module: Mathlib.Topology.Sheaves.Alexandrov

Goal state before:
pp: X✝ : Type v
inst✝⁶ : TopologicalSpace X✝
inst✝⁵ : Preorder X✝
inst✝⁴ : Topology.IsUpperSet X✝
C : Type u
inst✝³ : Category.{v, u} C
inst✝² : HasLimits C
F✝ : X✝ ⥤ C
X : TopCat
inst✝¹ : Preorder ↑X
inst✝ : Topology.IsUpperSet ↑X
F : ↑X ⥤ C
α : Type v
Us : α → Opens ↑X
S : Cone ((ObjectProperty.ι fun V ↦ ∃ i, V ≤ Us i).op ⋙ principalsKanExtension F)
m : S.pt ⟶ ((principalsKanExtension F).mapCone (opensLeCoverCocone Us).op).pt
hm :
  ∀ (j : (ObjectProperty.FullSubcategory fun V ↦ ∃ i, V ≤ Us i)ᵒᵖ),
    m ≫ ((principalsKanExtension F).mapCone (opensLeCoverCocone Us).op).π.app j = S.π.app j
⊢ limit.lift (generator (iSup Us) ⋙ F) (lowerCone Us S) = m

Tactic:
ext ⟨_, x, f⟩

Goal state after:
X✝ : Type v
inst✝⁶ : TopologicalSpace X✝
inst✝⁵ : Preorder X✝
inst✝⁴ : Topology.IsUpperSet X✝
C : Type u
inst✝³ : Category.{v, u} C
inst✝² : HasLimits C
F✝ : X✝ ⥤ C
X : TopCat
inst✝¹ : Preorder ↑X
inst✝ : Topology.IsUpperSet ↑X
F : ↑X ⥤ C
α : Type v
Us : α → Opens ↑X
S : Cone ((ObjectProperty.ι fun V ↦ ∃ i, V ≤ Us i).op ⋙ principalsKanExtension F)
m : S.pt ⟶ ((principalsKanExtension F).mapCone (opensLeCoverCocone Us).op).pt
hm :
  ∀ (j : (ObjectProperty.FullSubcategory fun V ↦ ∃ i, V ≤ Us i)ᵒᵖ),
    m ≫ ((principalsKanExtension F).mapCone (opensLeCoverCocone Us).op).π.app j = S.π.app j
left✝ : Discrete PUnit.{1}
x : ↑X
f : (fromPUnit (Opposite.op (iSup Us))).obj left✝ ⟶ (principals ↑X).obj x
⊢ limit.lift (generator (iSup Us) ⋙ F) (lowerCone Us S) ≫
      limit.π (generator (iSup Us) ⋙ F) { left := left✝, right := x, hom := f } =
    m ≫ limit.π (generator (iSup Us) ⋙ F) { left := left✝, right := x, hom := f }
Module: Mathlib.Topology.Sheaves.SheafCondition.EqualizerProducts

Goal state before:
pp: C : Type u
inst✝¹ : Category.{v, u} C
inst✝ : HasProducts C
X : TopCat
F : Presheaf C X
ι : Type v'
U : ι → Opens ↑X
⊢ res F U ≫ leftRes F U = res F U ≫ rightRes F U

Tactic:
dsimp [res, leftRes, rightRes]
  ext
  simp only [limit.lift_π, limit.lift_π_assoc, Fan.mk_π_app, Category.assoc]
  rw [← F.map_comp]
  rw [← F.map_comp]
  congr 1

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

Goal state before:
pp: X : Type u_1
inst✝ : UniformSpace X
u : Set X
x : X
uc s : SetRel X X
huc : IsOpen uc
ucu : uc ∈ 𝓤 X
hn : ball x (s ○ uc ○ s) ⊆ u
hs : s ∈ 𝓤 X
ds : SetRel X X
hdsu : ds ∈ 𝓤 X
hdso : IsOpen ds
hdsd : ds ○ ds ⊆ s
ho : IsOpen (ds ○ uc ○ ds)
hsub : ds ○ (ds ○ uc ○ ds) ○ ds ⊆ s ○ uc ○ s
⊢ ∃ v,
    IsOpen v ∧
      closure (ball x uc) ⊆ v ∧ closure v ⊆ u ∧ IsThickening (closure (ball x uc)) v ∧ IsThickening (closure v) u

Tactic:
replace hsub := (ball_mono hsub x).trans hn

Goal state after:
X : Type u_1
inst✝ : UniformSpace X
u : Set X
x : X
uc s : SetRel X X
huc : IsOpen uc
ucu : uc ∈ 𝓤 X
hn : ball x (s ○ uc ○ s) ⊆ u
hs : s ∈ 𝓤 X
ds : SetRel X X
hdsu : ds ∈ 𝓤 X
hdso : IsOpen ds
hdsd : ds ○ ds ⊆ s
ho : IsOpen (ds ○ uc ○ ds)
hsub : ball x (ds ○ (ds ○ uc ○ ds) ○ ds) ⊆ u
⊢ ∃ v,
    IsOpen v ∧
      closure (ball x uc) ⊆ v ∧ closure v ⊆ u ∧ IsThickening (closure (ball x uc)) v ∧ IsThickening (closure v) u
Module: Mathlib.Topology.UniformSpace.OfCompactT2

Goal state before:
pp: γ : Type u_1
inst✝² : TopologicalSpace γ
inst✝¹ : CompactSpace γ
inst✝ : R1Space γ
𝓝Δ : Filter (γ × γ) := 𝓝ˢ (diagonal γ)
F : Filter (γ × γ) := 𝓝Δ.lift' fun s ↦ s ○ s
V : Set (γ × γ)
V_in : V ∈ 𝓝Δ
H : ¬F ⊓ 𝓟 Vᶜ = ⊥
this : (F ⊓ 𝓟 Vᶜ).NeBot
x y : γ
hxy : ClusterPt (x, y) (F ⊓ 𝓟 Vᶜ)
clV : ClusterPt (x, y) (𝓟 Vᶜ)
ninsep_xy : ¬Inseparable x y
U₁ V₁ : Set γ
V₁_in : V₁ ∈ 𝓝 x
U₂ V₂ : Set γ
V₂_in : V₂ ∈ 𝓝 y
V₁_cl : IsClosed[inst✝²] V₁
V₂_cl : IsClosed[inst✝²] V₂
U₁_op : IsOpen[inst✝²] U₁
U₂_op : IsOpen[inst✝²] U₂
VU₁ : V₁ ⊆ U₁
VU₂ : V₂ ⊆ U₂
hU₁₂ : Disjoint U₁ U₂
U₃ : Set γ := (V₁ ∪ V₂)ᶜ
⊢ False

Tactic:
have U₃_op : IsOpen U₃ := (V₁_cl.union V₂_cl).isOpen_compl

Goal state after:
γ : Type u_1
inst✝² : TopologicalSpace γ
inst✝¹ : CompactSpace γ
inst✝ : R1Space γ
𝓝Δ : Filter (γ × γ) := 𝓝ˢ (diagonal γ)
F : Filter (γ × γ) := 𝓝Δ.lift' fun s ↦ s ○ s
V : Set (γ × γ)
V_in : V ∈ 𝓝Δ
H : ¬F ⊓ 𝓟 Vᶜ = ⊥
this : (F ⊓ 𝓟 Vᶜ).NeBot
x y : γ
hxy : ClusterPt (x, y) (F ⊓ 𝓟 Vᶜ)
clV : ClusterPt (x, y) (𝓟 Vᶜ)
ninsep_xy : ¬Inseparable x y
U₁ V₁ : Set γ
V₁_in : V₁ ∈ 𝓝 x
U₂ V₂ : Set γ
V₂_in : V₂ ∈ 𝓝 y
V₁_cl : IsClosed[inst✝²] V₁
V₂_cl : IsClosed[inst✝²] V₂
U₁_op : IsOpen[inst✝²] U₁
U₂_op : IsOpen[inst✝²] U₂
VU₁ : V₁ ⊆ U₁
VU₂ : V₂ ⊆ U₂
hU₁₂ : Disjoint U₁ U₂
U₃ : Set γ := (V₁ ∪ V₂)ᶜ
U₃_op : IsOpen[inst✝²] U₃
⊢ False
Module: Mathlib.Topology.Sion

Goal state before:
pp: case a.inl
E : Type u_1
F : Type u_2
β : Type u_3
inst✝¹¹ : LinearOrder β
X : Set E
f : E → F → β
inst✝¹⁰ : TopologicalSpace E
inst✝⁹ : AddCommGroup E
inst✝⁸ : Module ℝ E
inst✝⁷ : IsTopologicalAddGroup E
inst✝⁶ : ContinuousSMul ℝ E
ne_X : X.Nonempty
kX : IsCompact X
inst✝⁵ : TopologicalSpace F
inst✝⁴ : AddCommGroup F
inst✝³ : Module ℝ F
inst✝² : DenselyOrdered β
inst✝¹ : IsTopologicalAddGroup F
inst✝ : ContinuousSMul ℝ F
cX : Convex ℝ X
sup_y : E → β
inf_sup : β
hinf_sup : IsGLB {x | ∃ x_1 ∈ X, sup_y x_1 = x} inf_sup
inf_x : F → β
sup_inf : β
cY : Convex ℝ ∅
hfx : ∀ x ∈ X, UpperSemicontinuousOn (fun y ↦ f x y) ∅
hfx' : ∀ x ∈ X, QuasiconcaveOn ℝ ∅ fun y ↦ f x y
hfy hfy' hinf_x : True
hsup_inf : IsBot sup_inf
hsup_y : ∀ x ∈ X, sup_y x = sup_inf
⊢ {t | ∃ x ∈ X, sup_y x = t} = {sup_inf}

Tactic:
ext t

Goal state after:
case a.inl
E : Type u_1
F : Type u_2
β : Type u_3
inst✝¹¹ : LinearOrder β
X : Set E
f : E → F → β
inst✝¹⁰ : TopologicalSpace E
inst✝⁹ : AddCommGroup E
inst✝⁸ : Module ℝ E
inst✝⁷ : IsTopologicalAddGroup E
inst✝⁶ : ContinuousSMul ℝ E
ne_X : X.Nonempty
kX : IsCompact X
inst✝⁵ : TopologicalSpace F
inst✝⁴ : AddCommGroup F
inst✝³ : Module ℝ F
inst✝² : DenselyOrdered β
inst✝¹ : IsTopologicalAddGroup F
inst✝ : ContinuousSMul ℝ F
cX : Convex ℝ X
sup_y : E → β
inf_sup : β
hinf_sup : IsGLB {x | ∃ x_1 ∈ X, sup_y x_1 = x} inf_sup
inf_x : F → β
sup_inf : β
cY : Convex ℝ ∅
hfx : ∀ x ∈ X, UpperSemicontinuousOn (fun y ↦ f x y) ∅
hfx' : ∀ x ∈ X, QuasiconcaveOn ℝ ∅ fun y ↦ f x y
hfy hfy' hinf_x : True
hsup_inf : IsBot sup_inf
hsup_y : ∀ x ∈ X, sup_y x = sup_inf
t : β
⊢ t ∈ {t | ∃ x ∈ X, sup_y x = t} ↔ t ∈ {sup_inf}