mathlib-initiative/mathlib-tactics huggingface dataset:
Module: Mathlib.Algebra.Category.Grp.AB

Goal state before:
pp: J : Type u
inst✝¹ : SmallCategory J
inst✝ : IsFiltered J
X Y : Discrete J ⥤ AddCommGrpCat
f : X ⟶ Y
hf : Epi f
iX : limit X ≅ AddCommGrpCat.of ((i : J) → ↑(X.obj { as := i })) :=
  (Pi.isoLimit X).symm ≪≫
    (limit.isLimit (Discrete.functor fun j ↦ X.obj { as := j })).conePointUniqueUpToIso
      (AddCommGrpCat.HasLimit.productLimitCone fun j ↦ X.obj { as := j }).isLimit
iY : limit Y ≅ AddCommGrpCat.of ((i : J) → ↑(Y.obj { as := i })) :=
  (Pi.isoLimit Y).symm ≪≫
    (limit.isLimit (Discrete.functor fun j ↦ Y.obj { as := j })).conePointUniqueUpToIso
      (AddCommGrpCat.HasLimit.productLimitCone fun j ↦ Y.obj { as := j }).isLimit
this :
  (Pi.map fun i ↦ ⇑(ConcreteCategory.hom (f.app { as := i }))) = ⇑(ConcreteCategory.hom (iX.inv ≫ lim.map f ≫ iY.hom))
⊢ Epi (lim.map f)

Tactic:
suffices Epi (iX.hom ≫ (iX.inv ≫ lim.map f ≫ iY.hom) ≫ iY.inv) by simpa using this

Goal state after:
J : Type u
inst✝¹ : SmallCategory J
inst✝ : IsFiltered J
X Y : Discrete J ⥤ AddCommGrpCat
f : X ⟶ Y
hf : Epi f
iX : limit X ≅ AddCommGrpCat.of ((i : J) → ↑(X.obj { as := i })) :=
  (Pi.isoLimit X).symm ≪≫
    (limit.isLimit (Discrete.functor fun j ↦ X.obj { as := j })).conePointUniqueUpToIso
      (AddCommGrpCat.HasLimit.productLimitCone fun j ↦ X.obj { as := j }).isLimit
iY : limit Y ≅ AddCommGrpCat.of ((i : J) → ↑(Y.obj { as := i })) :=
  (Pi.isoLimit Y).symm ≪≫
    (limit.isLimit (Discrete.functor fun j ↦ Y.obj { as := j })).conePointUniqueUpToIso
      (AddCommGrpCat.HasLimit.productLimitCone fun j ↦ Y.obj { as := j }).isLimit
this :
  (Pi.map fun i ↦ ⇑(ConcreteCategory.hom (f.app { as := i }))) = ⇑(ConcreteCategory.hom (iX.inv ≫ lim.map f ≫ iY.hom))
⊢ Epi (iX.hom ≫ (iX.inv ≫ lim.map f ≫ iY.hom) ≫ iY.inv)
Module: Mathlib.CategoryTheory.Limits.Presheaf

Goal state before:
pp: C : Type u₁
inst✝¹ : Category.{v₁, u₁} C
inst✝ : LocallySmall.{w, v₁, u₁} C
F : C ⥤ Type w
X : C
G : F.Elementsᵒᵖ ⥤ Type w := (CategoryOfElements.π F).op ⋙ shrinkYoneda.{w, v₁, u₁}.obj X
c : G.CoconeTypes := G.coconeTypesEquiv.symm (coconeπOpCompShrinkYonedaObj F X)
x : F.obj X
u : F.Elements
v : u.fst ⟶ X
h : (ConcreteCategory.hom (F.map v)) u.snd = x
⊢ G.ιColimitType (op u)
      ((ConcreteCategory.hom
          (G.map
            (have this := ⟨v, h⟩;
              this).op))
        (shrinkYonedaObjObjEquiv.symm (𝟙 X))) =
    G.ιColimitType (op u) (shrinkYonedaObjObjEquiv.symm v)

Tactic:
simp [G, shrinkYoneda_obj_map_shrinkYonedaObjObjEquiv_symm.{w}]

Goal state after:
Module: Mathlib.Data.ZMod.IntUnitsPower

Goal state before:
pp: z₁ z₂ : ZMod 2
au : Additive ℤˣ
⊢ Additive.toMul ((z₁ + z₂) • au) = Additive.toMul (z₁ • au + z₂ • au)

Tactic:
by
    dsimp only [ZMod.smul_units_def, toMul_nsmul, toMul_add]
    rw [← pow_add, ZMod.val_add, ← Int.units_pow_eq_pow_mod_two]

Goal state after:
Module: Mathlib.Data.Nat.Factorization.Induction

Goal state before:
pp: a b m n✝ p✝ : ℕ
motive : ℕ → Sort u_1
zero : motive 0
one : motive 1
prime_pow_mul : (a p n : ℕ) → Prime p → ¬p ∣ a → 0 < n → motive a → motive (p ^ n * a)
n k : ℕ
hk : (m : ℕ) → m < k + 2 → motive m
p : ℕ := (k + 2).minFac
hp : Prime p
t : ℕ := (k + 2).factorization p
hpt : p ^ t ∣ k + 2
htp : 0 < t
⊢ k + 2 = p ^ t * ((k + 2) / p ^ t)

pp: case convert_1
a b m n✝ p✝ : ℕ
motive : ℕ → Sort u_1
zero : motive 0
one : motive 1
prime_pow_mul : (a p n : ℕ) → Prime p → ¬p ∣ a → 0 < n → motive a → motive (p ^ n * a)
n k : ℕ
hk : (m : ℕ) → m < k + 2 → motive m
p : ℕ := (k + 2).minFac
hp : Prime p
t : ℕ := (k + 2).factorization p
hpt : p ^ t ∣ k + 2
htp : 0 < t
⊢ ¬p ∣ (k + 2) / p ^ t

pp: case convert_2
a b m n✝ p✝ : ℕ
motive : ℕ → Sort u_1
zero : motive 0
one : motive 1
prime_pow_mul : (a p n : ℕ) → Prime p → ¬p ∣ a → 0 < n → motive a → motive (p ^ n * a)
n k : ℕ
hk : (m : ℕ) → m < k + 2 → motive m
p : ℕ := (k + 2).minFac
hp : Prime p
t : ℕ := (k + 2).factorization p
hpt : p ^ t ∣ k + 2
htp : 0 < t
⊢ k + 2 < p ^ t * (k + 2)

Tactic:
· rw [Nat.mul_div_cancel' hpt]

Goal state after:
case convert_1
a b m n✝ p✝ : ℕ
motive : ℕ → Sort u_1
zero : motive 0
one : motive 1
prime_pow_mul : (a p n : ℕ) → Prime p → ¬p ∣ a → 0 < n → motive a → motive (p ^ n * a)
n k : ℕ
hk : (m : ℕ) → m < k + 2 → motive m
p : ℕ := (k + 2).minFac
hp : Prime p
t : ℕ := (k + 2).factorization p
hpt : p ^ t ∣ k + 2
htp : 0 < t
⊢ ¬p ∣ (k + 2) / p ^ t

case convert_2
a b m n✝ p✝ : ℕ
motive : ℕ → Sort u_1
zero : motive 0
one : motive 1
prime_pow_mul : (a p n : ℕ) → Prime p → ¬p ∣ a → 0 < n → motive a → motive (p ^ n * a)
n k : ℕ
hk : (m : ℕ) → m < k + 2 → motive m
p : ℕ := (k + 2).minFac
hp : Prime p
t : ℕ := (k + 2).factorization p
hpt : p ^ t ∣ k + 2
htp : 0 < t
⊢ k + 2 < p ^ t * (k + 2)
Module: Mathlib.Algebra.Module.Injective

Goal state before:
pp: R : Type u
inst✝² : Ring R
M : Type v
inst✝¹ : AddCommGroup M
inst✝ : Module R M
inj : Injective R (ULift.{v', v} M)
X Y : Type v
x✝³ : AddCommGroup X
x✝² : AddCommGroup Y
x✝¹ : Module R X
x✝ : Module R Y
f : X →ₗ[R] Y
hf : Function.Injective ⇑f
g : X →ₗ[R] M
eX : ULift.{v', v} X ≃ₗ[R] X := ULift.moduleEquiv
g' : ULift.{v', v} Y →ₗ[R] ULift.{v', v} M
hg' : ∀ (x : ULift.{v', v} X), g' ((↑ULift.moduleEquiv.symm ∘ₗ f ∘ₗ ↑eX) x) = (↑ULift.moduleEquiv.symm ∘ₗ g ∘ₗ ↑eX) x
x : X
⊢ (↑ULift.moduleEquiv ∘ₗ g' ∘ₗ ↑ULift.moduleEquiv.symm) (f x) = g x

Tactic:
exact congr(ULift.down $(hg' ⟨x⟩))

Goal state after:
Module: Mathlib.Data.Nat.Totient

Goal state before:
pp: n : ℕ
hn : n ≠ 0
⊢ ∀ x ∈ n.factorization.support, φ (x ^ n.factorization x) = x ^ (n.factorization x - 1) * (x - 1)

Tactic:
intro p hp

Goal state after:
n : ℕ
hn : n ≠ 0
p : ℕ
hp : p ∈ n.factorization.support
⊢ φ (p ^ n.factorization p) = p ^ (n.factorization p - 1) * (p - 1)
Module: Mathlib.Order.Filter.Lift

Goal state before:
pp: α : Type u_1
β : Type u_2
ι : Sort u_4
inst✝ : Nonempty ι
f : ι → Filter α
g : Set α → Filter β
hg : ∀ (s t : Set α), g (s ∩ t) = g s ⊓ g t
s : Set β
t : Set α
⊢ t ∈ iInf f → ⨅ i, (f i).lift g ≤ g t

Tactic:
ht

Goal state after:
α : Type u_1
β : Type u_2
ι : Sort u_4
inst✝ : Nonempty ι
f : ι → Filter α
g : Set α → Filter β
hg : ∀ (s t : Set α), g (s ∩ t) = g s ⊓ g t
s : Set β
t : Set α
ht : t ∈ iInf f
⊢ ⨅ i, (f i).lift g ≤ g t
Module: Mathlib.Order.Filter.Lift

Goal state before:
pp: α : Type u_1
β : Type u_2
γ : Type u_3
f : Filter α
h : Set α → Set β
m : γ → β
⊢ comap m (f.lift' h) = f.lift' (preimage m ∘ h)

Tactic:
simp only [Filter.lift', comap_lift_eq, comp_def, comap_principal]

Goal state after:
Module: Mathlib.Algebra.Order.ToIntervalMod

Goal state before:
pp: α : Type u_1
inst✝² : AddCommGroup α
inst✝¹ : LinearOrder α
inst✝ : IsOrderedAddMonoid α
hα : Archimedean α
p : α
hp : 0 < p
a✝ b✝ c : α
n : ℤ
a : α
b : α ⧸ AddSubgroup.zmultiples p
⊢ (fun x ↦ ↑↑x) ((fun b ↦ ⟨⋯.lift b, ⋯⟩) b) = b

Tactic:
induction b using QuotientAddGroup.induction_on
    dsimp
    rw [QuotientAddGroup.eq_iff_sub_mem, toIocMod_sub_self]
    apply AddSubgroup.zsmul_mem_zmultiples

Goal state after:
Module: Mathlib.Topology.ClusterPt

Goal state before:
pp: case mpr.inr
X : Type u
inst✝ : TopologicalSpace X
x : X
C : Set X
h : AccPt x (𝓟 C)
⊢ ClusterPt x (𝓟 C)

Tactic:
· exact h.clusterPt

Goal state after:
Module: Mathlib.Topology.Maps.Basic

Goal state before:
pp: X : Type u_1
Y : Type u_2
f : X → Y
inst✝¹ : TopologicalSpace X
inst✝ : TopologicalSpace Y
hf : IsCoinducing f
hf' : Injective f
s : Set X
hs : IsOpen[inst✝¹] s
⊢ IsOpen[inst✝¹] (f ⁻¹' f '' s)

Tactic:
preimage_image_eq _ hf'

Goal state after:
X : Type u_1
Y : Type u_2
f : X → Y
inst✝¹ : TopologicalSpace X
inst✝ : TopologicalSpace Y
hf : IsCoinducing f
hf' : Injective f
s : Set X
hs : IsOpen[inst✝¹] s
⊢ IsOpen[inst✝¹] s
Module: Mathlib.Topology.Maps.Basic

Goal state before:
pp: X : Type u_1
Y : Type u_2
f : X → Y
inst✝¹ : TopologicalSpace X
inst✝ : TopologicalSpace Y
hf : IsInducing f
h : IsClosed[inst✝] (range f)
t : Set Y
ht : IsClosed[inst✝] t
hs : IsClosed[inst✝¹] (f ⁻¹' t)
⊢ IsClosed[inst✝] (t ∩ range f)

Tactic:
exact ht.inter h

Goal state after:
Module: Mathlib.Topology.NhdsWithin

Goal state before:
pp: α : Type u_1
inst✝ : TopologicalSpace α
a : α
s t : Set α
⊢ 𝓝 a ⊓ 𝓟 (s ∩ t) = 𝓝 a ⊓ 𝓟 s ⊓ 𝓟 t

Tactic:
rw [← inf_principal, inf_assoc]

Goal state after:
Module: Mathlib.Topology.ContinuousOn

Goal state before:
pp: case mp
α : Type u_1
β : Type u_2
inst✝¹ : TopologicalSpace α
inst✝ : TopologicalSpace β
f : α → β
s : Set α
hs : IsOpen[inst✝¹] s
h : ∀ (t : Set β), IsOpen[inst✝] t → ∃ u, IsOpen[inst✝¹] u ∧ f ⁻¹' t ∩ s = u ∩ s
t : Set β
⊢ IsOpen[inst✝] t → IsOpen[inst✝¹] (s ∩ f ⁻¹' t)

Tactic:
ht

Goal state after:
case mp
α : Type u_1
β : Type u_2
inst✝¹ : TopologicalSpace α
inst✝ : TopologicalSpace β
f : α → β
s : Set α
hs : IsOpen[inst✝¹] s
h : ∀ (t : Set β), IsOpen[inst✝] t → ∃ u, IsOpen[inst✝¹] u ∧ f ⁻¹' t ∩ s = u ∩ s
t : Set β
ht : IsOpen[inst✝] t
⊢ IsOpen[inst✝¹] (s ∩ f ⁻¹' t)
Module: Mathlib.Topology.ContinuousOn

Goal state before:
pp: case mpr
α : Type u_1
β : Type u_2
inst✝¹ : TopologicalSpace α
inst✝ : TopologicalSpace β
f : α → β
s : Set α
hs : IsOpen[inst✝¹] s
h : ∀ (t : Set β), IsOpen[inst✝] t → IsOpen[inst✝¹] (s ∩ f ⁻¹' t)
t : Set β
⊢ IsOpen[inst✝] t → ∃ u, IsOpen[inst✝¹] u ∧ f ⁻¹' t ∩ s = u ∩ s

Tactic:
ht

Goal state after:
case mpr
α : Type u_1
β : Type u_2
inst✝¹ : TopologicalSpace α
inst✝ : TopologicalSpace β
f : α → β
s : Set α
hs : IsOpen[inst✝¹] s
h : ∀ (t : Set β), IsOpen[inst✝] t → IsOpen[inst✝¹] (s ∩ f ⁻¹' t)
t : Set β
ht : IsOpen[inst✝] t
⊢ ∃ u, IsOpen[inst✝¹] u ∧ f ⁻¹' t ∩ s = u ∩ s
Module: Mathlib.Topology.Constructions.SumProd

Goal state before:
pp: X : Type u
Y : Type v
inst✝¹ : TopologicalSpace X
inst✝ : TopologicalSpace Y
s : Set X
t : Set Y
hs : Dense s
ht : Dense t
x : X × Y
⊢ x ∈ closure[instTopologicalSpaceProd] (s ×ˢ t)

Tactic:
by
  rw [closure_prod_eq]
  exact ⟨hs x.1, ht x.2⟩

Goal state after:
Module: Mathlib.Topology.ContinuousOn

Goal state before:
pp: α : Type u_1
β : Type u_2
inst✝¹ : TopologicalSpace α
inst✝ : TopologicalSpace β
f g : α → β
s s₁ : Set α
h : ContinuousOn f s
h' : EqOn g f s₁
h₁ : s₁ ⊆ s
x : α
hx : x ∈ s₁
A : Tendsto f (𝓝[s₁] x) (𝓝 (f x))
⊢ Tendsto g (𝓝[s₁] x) (𝓝 (g x))

Tactic:
rw [← h' hx] at A

Goal state after:
α : Type u_1
β : Type u_2
inst✝¹ : TopologicalSpace α
inst✝ : TopologicalSpace β
f g : α → β
s s₁ : Set α
h : ContinuousOn f s
h' : EqOn g f s₁
h₁ : s₁ ⊆ s
x : α
hx : x ∈ s₁
A : Tendsto f (𝓝[s₁] x) (𝓝 (g x))
⊢ Tendsto g (𝓝[s₁] x) (𝓝 (g x))
Module: Mathlib.Topology.Constructions

Goal state before:
pp: X : Type u
inst✝ : TopologicalSpace X
Y : Type u_5
p : X → Prop
l : Filter Y
f : Y → Subtype p
a : X
ha : p a
⊢ Tendsto f l (𝓝 ⟨a, ha⟩) ↔ Tendsto (fun x ↦ ↑(f x)) l (𝓝 ↑⟨a, ha⟩)

Tactic:
by rw [nhds_subtype_eq_comap, tendsto_comap_iff]; rfl

Goal state after:
Module: Mathlib.Topology.Constructions

Goal state before:
pp: X : Type u
Y : Type v
inst✝¹ : TopologicalSpace X
inst✝ : TopologicalSpace Y
f : X → Y
s : Set Y
hs : ∀ (a : X), f a ∈ s
hf : ∀ (s_1 : Set ↑s), IsOpen[instTopologicalSpaceSubtype] s_1 → IsOpen[inst✝¹] (codRestrict f s hs ⁻¹' s_1)
t : Set Y
⊢ IsOpen[inst✝] t → IsOpen[inst✝¹] (f ⁻¹' t)

Tactic:
ht

Goal state after:
X : Type u
Y : Type v
inst✝¹ : TopologicalSpace X
inst✝ : TopologicalSpace Y
f : X → Y
s : Set Y
hs : ∀ (a : X), f a ∈ s
hf : ∀ (s_1 : Set ↑s), IsOpen[instTopologicalSpaceSubtype] s_1 → IsOpen[inst✝¹] (codRestrict f s hs ⁻¹' s_1)
t : Set Y
ht : IsOpen[inst✝] t
⊢ IsOpen[inst✝¹] (f ⁻¹' t)
Module: Mathlib.Topology.Bases

Goal state before:
pp: α : Type u
t : TopologicalSpace α
a : α
s : Set α
b : Set (Set α)
hb : IsTopologicalBasis b
⊢ s ∈ (𝓝 a).sets ↔ ∃ t ∈ b, a ∈ t ∧ t ⊆ s

Tactic:
hb.eq_generateFrom,

Goal state after:
α : Type u
t : TopologicalSpace α
a : α
s : Set α
b : Set (Set α)
hb : IsTopologicalBasis b
⊢ s ∈ (𝓝 a).sets ↔ ∃ t ∈ b, a ∈ t ∧ t ⊆ s
Module: Mathlib.Topology.ContinuousOn

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
inst✝ : DiscreteTopology α
f : α × β → γ
s : Set (α × β)
x : α × β
⊢ Tendsto f (pure x.1 ×ˢ 𝓝 x.2 ⊓ 𝓟 s) (𝓝 (f (x.1, x.2))) ↔
    Tendsto (fun x_1 ↦ f (x.1, x_1)) (𝓝 x.2 ⊓ 𝓟 {b | (x.1, b) ∈ s}) (𝓝 (f (x.1, x.2)))

Tactic:
pure_prod,

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
inst✝ : DiscreteTopology α
f : α × β → γ
s : Set (α × β)
x : α × β
⊢ Tendsto f (map (Prod.mk x.1) (𝓝 x.2) ⊓ 𝓟 s) (𝓝 (f (x.1, x.2))) ↔
    Tendsto (fun x_1 ↦ f (x.1, x_1)) (𝓝 x.2 ⊓ 𝓟 {b | (x.1, b) ∈ s}) (𝓝 (f (x.1, x.2)))
Module: Mathlib.Topology.Constructions

Goal state before:
pp: X : Type u
inst✝ : TopologicalSpace X
s : Set X
hs : ∀ (U : Set X), IsOpen[inst✝] U → U.Nonempty → (U ∩ s).Nonempty
u : Set ↑s
hud : ∀ (U : Set ↑s), IsOpen[instTopologicalSpaceSubtype] U → U.Nonempty → (U ∩ u).Nonempty
v : Set X
hv1 : IsOpen[inst✝] v
hv2 : Subtype.val ⁻¹' v = u
t : Set X
⊢ IsOpen[inst✝] t → t.Nonempty → (t ∩ v).Nonempty

Tactic:
ht

Goal state after:
X : Type u
inst✝ : TopologicalSpace X
s : Set X
hs : ∀ (U : Set X), IsOpen[inst✝] U → U.Nonempty → (U ∩ s).Nonempty
u : Set ↑s
hud : ∀ (U : Set ↑s), IsOpen[instTopologicalSpaceSubtype] U → U.Nonempty → (U ∩ u).Nonempty
v : Set X
hv1 : IsOpen[inst✝] v
hv2 : Subtype.val ⁻¹' v = u
t : Set X
ht : IsOpen[inst✝] t
⊢ t.Nonempty → (t ∩ v).Nonempty
Module: Mathlib.Topology.ContinuousOn

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
inst✝ : DiscreteTopology α
f : α × β → γ
⊢ (∀ (a : α) (b : β), 𝓝 (f (a, b)) ≤ map f (pure a ×ˢ 𝓝 b)) ↔
    ∀ (a : α) (x : β), 𝓝 (f (a, x)) ≤ map (fun x ↦ f (a, x)) (𝓝 x)

Tactic:
pure_prod,

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
inst✝ : DiscreteTopology α
f : α × β → γ
⊢ (∀ (a : α) (b : β), 𝓝 (f (a, b)) ≤ map f (map (Prod.mk a) (𝓝 b))) ↔
    ∀ (a : α) (x : β), 𝓝 (f (a, x)) ≤ map (fun x ↦ f (a, x)) (𝓝 x)
Module: Mathlib.Topology.Constructions.SumProd

Goal state before:
pp: X : Type u
Y : Type v
Z : Type u_2
inst✝² : TopologicalSpace X
inst✝¹ : TopologicalSpace Y
inst✝ : TopologicalSpace Z
f : X → Z
g : Y → Z
⊢ (IsInducing f ∧
        IsInducing g ∧ Disjoint (closure[inst✝] (range f)) (range g) ∧ Disjoint (range f) (closure[inst✝] (range g))) ∧
      Injective (Sum.elim f g) ↔
    (IsInducing f ∧ Injective f) ∧
      (IsInducing g ∧ Injective g) ∧
        Disjoint (closure[inst✝] (range f)) (range g) ∧ Disjoint (range f) (closure[inst✝] (range g))

Tactic:
Sum.elim_injective

Goal state after:
X : Type u
Y : Type v
Z : Type u_2
inst✝² : TopologicalSpace X
inst✝¹ : TopologicalSpace Y
inst✝ : TopologicalSpace Z
f : X → Z
g : Y → Z
⊢ ((IsInducing f ∧
        IsInducing g ∧ Disjoint (closure[inst✝] (range f)) (range g) ∧ Disjoint (range f) (closure[inst✝] (range g))) ∧
      Injective f ∧ Injective g ∧ ∀ (a : X) (b : Y), f a ≠ g b) ↔
    (IsInducing f ∧ Injective f) ∧
      (IsInducing g ∧ Injective g) ∧
        Disjoint (closure[inst✝] (range f)) (range g) ∧ Disjoint (range f) (closure[inst✝] (range g))
Module: Mathlib.Topology.Constructions

Goal state before:
pp: case refine_2
ι : Type u_5
A : ι → Type u_6
T : (i : ι) → TopologicalSpace (A i)
s : Set ((a : ι) → A a)
a : (a : ι) → A a
x✝ : a ∈ s
I : Finset ι
t : (a : ι) → Set (A a)
h1 : ∀ a_1 ∈ I, IsOpen[T a_1] (t a_1) ∧ a a_1 ∈ t a_1
h2 : (↑I).pi t ⊆ s
⊢ ∃ I t, (∀ (i : ι), ∃ t_1 ⊆ t i, IsOpen[T i] t_1 ∧ a i ∈ t_1) ∧ (↑I).pi t ⊆ s

Tactic:
refine ⟨I, fun a => ite (a ∈ I) (t a) univ, fun i => ?_, ?_⟩
    · by_cases hi : i ∈ I
      · use t i
        simp_rw [if_pos hi]
        exact ⟨Subset.rfl, (h1 i) hi⟩
      · use univ
        simp_rw [if_neg hi]
        exact ⟨Subset.rfl, isOpen_univ, mem_univ _⟩
    · rw [← univ_pi_ite]
      simp only [← ite_and, ← Finset.mem_coe, and_self_iff, univ_pi_ite, h2]

Goal state after:
Module: Mathlib.Topology.Bases

Goal state before:
pp: case refine_2.a
α : Type u_1
ts : TopologicalSpace α
inst✝ : SecondCountableTopology α
t : Set (Set α)
ht : ts = generateFrom t
t' : Set (Set α) := (fun f ↦ ⋂₀ f) '' {f | f.Finite ∧ f ⊆ t}
this : IsTopologicalBasis t'
s' : Set (Set α)
s't' : s' ⊆ t'
s'_count : s'.Countable
hs' : IsTopologicalBasis s'
f : Set α → Set (Set α)
f_fin : ∀ u ∈ s', (f u).Finite
ft : ∀ u ∈ s', f u ⊆ t
hf : ∀ u ∈ s', ⋂₀ f u = u
u : Set α
hu : u ∈ s'
v : Set α
hv : v ∈ f u
⊢ v ∈ {s | IsOpen[ts] s}

Tactic:
ht

Goal state after:
case refine_2.a
α : Type u_1
ts : TopologicalSpace α
inst✝ : SecondCountableTopology α
t : Set (Set α)
ht : ts = generateFrom t
t' : Set (Set α) := (fun f ↦ ⋂₀ f) '' {f | f.Finite ∧ f ⊆ t}
this : IsTopologicalBasis t'
s' : Set (Set α)
s't' : s' ⊆ t'
s'_count : s'.Countable
hs' : IsTopologicalBasis s'
f : Set α → Set (Set α)
f_fin : ∀ u ∈ s', (f u).Finite
ft : ∀ u ∈ s', f u ⊆ t
hf : ∀ u ∈ s', ⋂₀ f u = u
u : Set α
hu : u ∈ s'
v : Set α
hv : v ∈ f u
⊢ v ∈ {s | IsOpen[generateFrom t] s}
Module: Mathlib.Topology.Compactness.Compact

Goal state before:
pp: X : Type u
inst✝ : TopologicalSpace X
s : Set X
ι : Type v
hs : IsCompact s
t : ι → Set X
htc : ∀ (i : ι), IsClosed[inst✝] (t i)
hst : ∀ (u : Finset ι), (s ∩ ⋂ i ∈ u, t i).Nonempty
⊢ (s ∩ ⋂ i, t i).Nonempty

Tactic:
by
  contrapose! hst
  exact hs.elim_finite_subfamily_closed t htc hst

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

Goal state before:
pp: X : Type u
Y : Type v
inst✝¹ : TopologicalSpace X
inst✝ : TopologicalSpace Y
f : X → Y
hf : Continuous[inst✝¹, inst✝] f
t : Set X
⊢ IsCompact t → ∃ i, IsCompact i ∧ f ⁻¹' iᶜ ⊆ tᶜ

Tactic:
ht

Goal state after:
X : Type u
Y : Type v
inst✝¹ : TopologicalSpace X
inst✝ : TopologicalSpace Y
f : X → Y
hf : Continuous[inst✝¹, inst✝] f
t : Set X
ht : IsCompact t
⊢ ∃ i, IsCompact i ∧ f ⁻¹' iᶜ ⊆ tᶜ
Module: Mathlib.Topology.Compactness.Compact

Goal state before:
pp: ι : Type u_1
X : ι → Type u_2
inst✝ : (i : ι) → TopologicalSpace (X i)
u : Set ((i : ι) × X i)
hu : IsCompact u
⊢ ∃ s t, s.Finite ∧ (∀ (i : ι), IsCompact (t i)) ∧ s.sigma t = u

Tactic:
obtain ⟨s, hs⟩ := hu.elim_finite_subcover (fun i : ι ↦ Sigma.mk i '' Sigma.mk i ⁻¹' Set.univ)
    (fun i ↦ isOpenMap_sigmaMk _ <| isOpen_univ.preimage continuous_sigmaMk)
    fun x hx ↦ (by simp)
  use s, fun i ↦ Sigma.mk i ⁻¹' u, s.finite_toSet, fun i ↦ ?_, ?_
  · exact Topology.IsClosedEmbedding.sigmaMk.isCompact_preimage hu
  · ext x
    simp only [Set.mem_sigma_iff, Finset.mem_coe, Set.mem_preimage, and_iff_right_iff_imp]
    intro hx
    obtain ⟨i, hi⟩ := Set.mem_iUnion.mp (hs hx)
    simp_all

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

Goal state before:
pp: case inl
X : Type u_1
inst✝¹ : TopologicalSpace X
inst✝ : T1Space X
p : X → Prop
a : X
ha : a ∈ {x | ∀ᶠ (y : X) in 𝓝[≠] x, p y}
hb : ∀ᶠ (x : X) in 𝓝[≠] a, p x
⊢ ∀ᶠ (y : X) in 𝓝[≠] a, p y

pp: case inr
X : Type u_1
inst✝¹ : TopologicalSpace X
inst✝ : T1Space X
p : X → Prop
a : X
ha : a ∈ {x | ∀ᶠ (y : X) in 𝓝[≠] x, p y}
b : X
hb : ∀ᶠ (x : X) in 𝓝[{a}ᶜ] b, p x
h : a ≠ b
⊢ ∀ᶠ (y : X) in 𝓝[≠] b, p y

Tactic:
· exact hb

Goal state after:
case inr
X : Type u_1
inst✝¹ : TopologicalSpace X
inst✝ : T1Space X
p : X → Prop
a : X
ha : a ∈ {x | ∀ᶠ (y : X) in 𝓝[≠] x, p y}
b : X
hb : ∀ᶠ (x : X) in 𝓝[{a}ᶜ] b, p x
h : a ≠ b
⊢ ∀ᶠ (y : X) in 𝓝[≠] b, p y
Module: Mathlib.Topology.Separation.Basic

Goal state before:
pp: X : Type u_1
inst✝¹ : TopologicalSpace X
inst✝ : R1Space X
s : Set X
hs : IsCompact s
ι : Type u_3
t : Finset ι
U : ι → Set X
hU : ∀ i ∈ t, IsOpen[inst✝¹] (U i)
hsC : s ⊆ ⋃ i ∈ t, U i
⊢ ∃ K, (∀ (i : ι), IsCompact (K i)) ∧ (∀ (i : ι), K i ⊆ U i) ∧ s = ⋃ i ∈ t, K i

Tactic:
induction t using Finset.induction generalizing U s with
  | empty =>
    refine ⟨fun _ => ∅, fun _ => isCompact_empty, fun i => empty_subset _, ?_⟩
    simpa only [subset_empty_iff, Finset.notMem_empty, iUnion_false, iUnion_empty] using hsC
  | insert x t hx ih =>
    simp only [Finset.set_biUnion_insert] at hsC
    simp only [Finset.forall_mem_insert] at hU
    have hU' : ∀ i ∈ t, IsOpen (U i) := fun i hi => hU.2 i hi
    rcases hs.binary_compact_cover hU.1 (isOpen_biUnion hU') hsC with
      ⟨K₁, K₂, h1K₁, h1K₂, h2K₁, h2K₂, hK⟩
    rcases ih h1K₂ U hU' h2K₂ with ⟨K, h1K, h2K, h3K⟩
    refine ⟨update K x K₁, ?_, ?_, ?_⟩
    · intro i
      rcases eq_or_ne i x with rfl | hi
      · simp only [update_self, h1K₁]
      · simp only [update_of_ne hi, h1K]
    · intro i
      rcases eq_or_ne i x with rfl | hi
      · simp only [update_self, h2K₁]
      · simp only [update_of_ne hi, h2K]
    · simp only [Finset.set_biUnion_insert_update _ hx, hK, h3K]

Goal state after:
Module: Mathlib.Topology.Connected.Basic

Goal state before:
pp: α : Type u
inst✝ : TopologicalSpace α
ι : Type u_3
t : Set ι
s : ι → Set α
H : ∀ i ∈ t, IsPreconnected (s i)
K : ∀ i ∈ t, ∀ j ∈ t, ReflTransGen (fun i j ↦ (s i ∩ s j).Nonempty ∧ i ∈ t) i j
R : ι → ι → Prop := fun i j ↦ (s i ∩ s j).Nonempty ∧ i ∈ t
⊢ IsPreconnected (⋃ n ∈ t, s n)

Tactic:
have P : ∀ i, i ∈ t → ∀ j, j ∈ t → ReflTransGen R i j →
      ∃ p, p ⊆ t ∧ i ∈ p ∧ j ∈ p ∧ IsPreconnected (⋃ j ∈ p, s j) := fun i hi j hj h => by
    induction h with
    | refl =>
      refine ⟨{i}, singleton_subset_iff.mpr hi, mem_singleton i, mem_singleton i, ?_⟩
      rw [biUnion_singleton]
      exact H i hi
    | @tail j k _ hjk ih =>
      obtain ⟨p, hpt, hip, hjp, hp⟩ := ih hjk.2
      refine ⟨insert k p, insert_subset_iff.mpr ⟨hj, hpt⟩, mem_insert_of_mem k hip,
        mem_insert k p, ?_⟩
      rw [biUnion_insert]
      refine (H k hj).union' (hjk.1.mono ?_) hp
      rw [inter_comm]
      exact inter_subset_inter_right _ (subset_biUnion_of_mem hjp)

Goal state after:
α : Type u
inst✝ : TopologicalSpace α
ι : Type u_3
t : Set ι
s : ι → Set α
H : ∀ i ∈ t, IsPreconnected (s i)
K : ∀ i ∈ t, ∀ j ∈ t, ReflTransGen (fun i j ↦ (s i ∩ s j).Nonempty ∧ i ∈ t) i j
R : ι → ι → Prop := fun i j ↦ (s i ∩ s j).Nonempty ∧ i ∈ t
P : ∀ i ∈ t, ∀ j ∈ t, ReflTransGen R i j → ∃ p ⊆ t, i ∈ p ∧ j ∈ p ∧ IsPreconnected (⋃ j ∈ p, s j)
⊢ IsPreconnected (⋃ n ∈ t, s n)
Module: Mathlib.Topology.Connected.Basic

Goal state before:
pp: α : Type u
inst✝ : TopologicalSpace α
ι : Type u_3
s : ι → Set α
hs : IsPreconnected (⋃ n, s n)
hs' : ∀ (i : ι), IsOpen[inst✝] (s i)
i j : ι
hij : ¬TransGen (fun a b ↦ (s a ∩ s b).Nonempty) i j
S : Set ι := {k | TransGen (fun a b ↦ (s a ∩ s b).Nonempty) i k}
U : Set α := ⋃ k ∈ S, s k
V : Set α := ⋃ k ∈ Sᶜ, s k
hsplit : ⋃ n, s n = U ∪ V
a : α
ha : a ∈ s i
b : α
hb : b ∈ s j
⊢ False

Tactic:
let hi_S : i ∈ S := Relation.TransGen.single ⟨a, ha, ha⟩

Goal state after:
α : Type u
inst✝ : TopologicalSpace α
ι : Type u_3
s : ι → Set α
hs : IsPreconnected (⋃ n, s n)
hs' : ∀ (i : ι), IsOpen[inst✝] (s i)
i j : ι
hij : ¬TransGen (fun a b ↦ (s a ∩ s b).Nonempty) i j
S : Set ι := {k | TransGen (fun a b ↦ (s a ∩ s b).Nonempty) i k}
U : Set α := ⋃ k ∈ S, s k
V : Set α := ⋃ k ∈ Sᶜ, s k
hsplit : ⋃ n, s n = U ∪ V
a : α
ha : a ∈ s i
b : α
hb : b ∈ s j
hi_S : i ∈ S := TransGen.single (Exists.intro a ⟨ha, ha⟩)
⊢ False
Module: Mathlib.Order.Filter.CountableInter

Goal state before:
pp: ι : Sort u_1
α : Type u_2
β : Type u_3
l : Filter α
inst✝ : CountableInterFilter l
⊢ CountableInterFilter ⊥

Tactic:
← principal_empty

Goal state after:
ι : Sort u_1
α : Type u_2
β : Type u_3
l : Filter α
inst✝ : CountableInterFilter l
⊢ CountableInterFilter (𝓟 ∅)
Module: Mathlib.Topology.Connected.Clopen

Goal state before:
pp: case refine_1.inr
ι : Type u_1
X : ι → Type u_2
hι : Nonempty ι
inst✝ : (i : ι) → TopologicalSpace (X i)
s : Set ((i : ι) × X i)
hs : IsPreconnected s
h : s.Nonempty
⊢ ∃ i t, IsPreconnected t ∧ s = mk i '' t

Tactic:
obtain ⟨a, t, ht, rfl⟩ := Sigma.isConnected_iff.1 ⟨h, hs⟩

Goal state after:
case refine_1.inr
ι : Type u_1
X : ι → Type u_2
hι : Nonempty ι
inst✝ : (i : ι) → TopologicalSpace (X i)
a : ι
t : Set (X a)
ht : IsConnected t
hs : IsPreconnected (mk a '' t)
h : (mk a '' t).Nonempty
⊢ ∃ i t_1, IsPreconnected t_1 ∧ mk a '' t = mk i '' t_1