mathlib-initiative/mathlib-tactics huggingface dataset:
Module: Mathlib.Topology.Connected.Basic

Goal state before:
pp: case tail
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
i : ι
hi : i ∈ t
j✝ j k : ι
a✝ : ReflTransGen R i j
hjk : R j k
ih : j ∈ t → ∃ p ⊆ t, i ∈ p ∧ j ∈ p ∧ IsPreconnected (⋃ j ∈ p, s j)
hj : k ∈ t
p : Set ι
hpt : p ⊆ t
hip : i ∈ p
hjp : j ∈ p
hp : IsPreconnected (⋃ j ∈ p, s j)
⊢ ∃ p ⊆ t, i ∈ p ∧ k ∈ p ∧ IsPreconnected (⋃ j ∈ p, s j)

Tactic:
refine ⟨insert k p, insert_subset_iff.mpr ⟨hj, hpt⟩, mem_insert_of_mem k hip,
        mem_insert k p, ?_⟩

Goal state after:
case tail
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
i : ι
hi : i ∈ t
j✝ j k : ι
a✝ : ReflTransGen R i j
hjk : R j k
ih : j ∈ t → ∃ p ⊆ t, i ∈ p ∧ j ∈ p ∧ IsPreconnected (⋃ j ∈ p, s j)
hj : k ∈ t
p : Set ι
hpt : p ⊆ t
hip : i ∈ p
hjp : j ∈ p
hp : IsPreconnected (⋃ j ∈ p, s j)
⊢ IsPreconnected (⋃ j ∈ insert k p, s j)
Module: Mathlib.Topology.Connected.LocallyConnected

Goal state before:
pp: case mpr
α : Type u
inst✝ : TopologicalSpace α
h : ∀ (F : Set α), IsOpen[inst✝] F → ∀ x ∈ F, IsOpen[inst✝] (connectedComponentIn F x)
⊢ LocallyConnectedSpace α

Tactic:
locallyConnectedSpace_iff_subsets_isOpen_isConnected

Goal state after:
case mpr
α : Type u
inst✝ : TopologicalSpace α
h : ∀ (F : Set α), IsOpen[inst✝] F → ∀ x ∈ F, IsOpen[inst✝] (connectedComponentIn F x)
⊢ ∀ (x : α), ∀ U ∈ 𝓝 x, ∃ V ⊆ U, IsOpen[inst✝] V ∧ x ∈ V ∧ IsConnected V
Module: Mathlib.Topology.Connected.LocallyConnected

Goal state before:
pp: case mp
α : Type u
inst✝ : TopologicalSpace α
⊢ LocallyConnectedSpace α → ∀ (x : α), ∀ U ∈ 𝓝 x, ∃ V ∈ 𝓝 x, IsPreconnected V ∧ V ⊆ U

Tactic:
locallyConnectedSpace_iff_subsets_isOpen_isConnected

Goal state after:
case mp
α : Type u
inst✝ : TopologicalSpace α
⊢ (∀ (x : α), ∀ U ∈ 𝓝 x, ∃ V ⊆ U, IsOpen[inst✝] V ∧ x ∈ V ∧ IsConnected V) →
    ∀ (x : α), ∀ U ∈ 𝓝 x, ∃ V ∈ 𝓝 x, IsPreconnected V ∧ V ⊆ U
Module: Mathlib.Topology.Connected.Clopen

Goal state before:
pp: case refine_2
ι : Type u_1
X : ι → Type u_2
inst✝ : (i : ι) → TopologicalSpace (X i)
s : Set ((i : ι) × X i)
⊢ (∃ i t, IsConnected t ∧ s = mk i '' t) → IsConnected s

Tactic:
rintro ⟨i, t, ht, rfl⟩
    exact ht.image _ continuous_sigmaMk.continuousOn

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

Goal state before:
pp: X : Type u
inst✝ : TopologicalSpace X
s : Set X
h :
  ∀ {ι : Type u} (t : ι → Set X),
    (∀ (i : ι), IsClosed[inst✝] (t i)) → s ∩ ⋂ i, t i = ∅ → ∃ u, u.Countable ∧ s ∩ ⋂ i ∈ u, t i = ∅
ι✝ : Type u
U : ι✝ → Set X
hUo : ∀ (i : ι✝), IsOpen[inst✝] (U i)
hsU : s ⊓ ⋂ i, (U i)ᶜ = ⊥
t : Set ι✝
ht : t.Countable ∧ s ∩ ⋂ i ∈ t, (U i)ᶜ = ∅
⊢ t.Countable ∧ Disjoint s (⋃ i ∈ t, U i)ᶜ

Tactic:
compl_iUnion₂,

Goal state after:
X : Type u
inst✝ : TopologicalSpace X
s : Set X
h :
  ∀ {ι : Type u} (t : ι → Set X),
    (∀ (i : ι), IsClosed[inst✝] (t i)) → s ∩ ⋂ i, t i = ∅ → ∃ u, u.Countable ∧ s ∩ ⋂ i ∈ u, t i = ∅
ι✝ : Type u
U : ι✝ → Set X
hUo : ∀ (i : ι✝), IsOpen[inst✝] (U i)
hsU : s ⊓ ⋂ i, (U i)ᶜ = ⊥
t : Set ι✝
ht : t.Countable ∧ s ∩ ⋂ i ∈ t, (U i)ᶜ = ∅
⊢ t.Countable ∧ Disjoint s (⋂ i ∈ t, (U i)ᶜ)
Module: Mathlib.Topology.Separation.Regular

Goal state before:
pp: case a
X : Type u_1
inst✝¹ : TopologicalSpace X
inst✝ : RegularSpace X
s : Set X
hs : IsCompact s
⊢ closure[inst✝¹] s ⊆ nhdsKer s

Tactic:
nhdsKer,

Goal state after:
case a
X : Type u_1
inst✝¹ : TopologicalSpace X
inst✝ : RegularSpace X
s : Set X
hs : IsCompact s
⊢ closure[inst✝¹] s ⊆ (𝓝ˢ s).ker
Module: Mathlib.Topology.Compactness.Lindelof

Goal state before:
pp: case mp
X : Type u
ι : Type u_1
inst✝ : TopologicalSpace X
b : ι → Set X
hb : IsTopologicalBasis (range b)
hb' : ∀ (i : ι), IsLindelof (b i)
Y : Type u
f : Y → Set X
h₁ : IsLindelof (⋃ i, f i)
h₂ : IsOpen[inst✝] (⋃ i, f i)
f' : Y → ι
hf' : ∀ (i : Y), b (f' i) = f i
⊢ ∃ s, s.Countable ∧ ⋃ i, f i = ⋃ i ∈ s, b i

Tactic:
have : b ∘ f' = f := funext hf'

Goal state after:
case mp
X : Type u
ι : Type u_1
inst✝ : TopologicalSpace X
b : ι → Set X
hb : IsTopologicalBasis (range b)
hb' : ∀ (i : ι), IsLindelof (b i)
Y : Type u
f : Y → Set X
h₁ : IsLindelof (⋃ i, f i)
h₂ : IsOpen[inst✝] (⋃ i, f i)
f' : Y → ι
hf' : ∀ (i : Y), b (f' i) = f i
this : b ∘ f' = f
⊢ ∃ s, s.Countable ∧ ⋃ i, f i = ⋃ i ∈ s, b i
Module: Mathlib.Topology.Compactness.Lindelof

Goal state before:
pp: X : Type u
inst✝² : TopologicalSpace X
inst✝¹ : HereditarilyLindelofSpace X
ι : Type u_2
inst✝ : Nonempty ι
U : ι → Set X
h : ∀ (i : ι), IsOpen[inst✝²] (U i)
⊢ ∃ k, ⋃ n, U (k n) = ⋃ i, U i

Tactic:
obtain ⟨t, htc, htu⟩ := eq_open_union_countable U h
  rcases eq_empty_or_nonempty t with rfl | t_ne
  · simp_rw [mem_empty_iff_false, iUnion_false, iUnion_empty, eq_comm (a := ∅), iUnion_eq_empty]
      at htu
    simp [htu]
  · obtain ⟨k, rfl⟩ := htc.exists_eq_range t_ne
    use k
    rwa [biUnion_range] at htu

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

Goal state before:
pp: case inl
α : Type u
β : Type v
inst✝¹ : TopologicalSpace α
inst✝ : TopologicalSpace β
f : α → β
connected_fibers : ∀ (t : β), IsConnected (f ⁻¹' {t})
hcl : IsCoinducing f
t : Set β
ht : IsClosed[inst✝] t
ht' : IsConnected t
hf : Surjective f
hT : IsClosed[inst✝¹] (f ⁻¹' t)
u v : Set α
hu : IsClosed[inst✝¹] u
hv : IsClosed[inst✝¹] v
huv : f ⁻¹' t ⊆ u ∪ v
uv_disj : Disjoint u v
T₁ : Set β := ⋯
T₂ : Set β := ⋯
fiber_decomp : ∀ t' ∈ t, f ⁻¹' {t'} ⊆ u ∨ f ⁻¹' {t'} ⊆ v
T₁_u : f ⁻¹' T₁ = f ⁻¹' t ∩ u
T₂_v : f ⁻¹' T₂ = f ⁻¹' t ∩ v
hT₁ : IsClosed[inst✝] T₁
hT₂ : IsClosed[inst✝] T₂
T_decomp : t ⊆ T₁ ∪ T₂
T_disjoint : Disjoint T₁ T₂
h : t ⊆ T₁
⊢ f ⁻¹' t ⊆ u

Tactic:
Subset.antisymm_iff

Goal state after:
case inl
α : Type u
β : Type v
inst✝¹ : TopologicalSpace α
inst✝ : TopologicalSpace β
f : α → β
connected_fibers : ∀ (t : β), IsConnected (f ⁻¹' {t})
hcl : IsCoinducing f
t : Set β
ht : IsClosed[inst✝] t
ht' : IsConnected t
hf : Surjective f
hT : IsClosed[inst✝¹] (f ⁻¹' t)
u v : Set α
hu : IsClosed[inst✝¹] u
hv : IsClosed[inst✝¹] v
huv : f ⁻¹' t ⊆ u ∪ v
uv_disj : Disjoint u v
T₁ : Set β := {t' | t' ∈ t ∧ f ⁻¹' {t'} ⊆ u}
T₂ : Set β := {t' | t' ∈ t ∧ f ⁻¹' {t'} ⊆ v}
fiber_decomp : ∀ t' ∈ t, f ⁻¹' {t'} ⊆ u ∨ f ⁻¹' {t'} ⊆ v
T₁_u : f ⁻¹' T₁ ⊆ f ⁻¹' t ∩ u ∧ f ⁻¹' t ∩ u ⊆ f ⁻¹' T₁
T₂_v : f ⁻¹' T₂ = f ⁻¹' t ∩ v
hT₁ : IsClosed[inst✝] T₁
hT₂ : IsClosed[inst✝] T₂
T_decomp : t ⊆ T₁ ∪ T₂
T_disjoint : Disjoint T₁ T₂
h : t ⊆ T₁
⊢ f ⁻¹' t ⊆ u
Module: Mathlib.Topology.Connected.Clopen

Goal state before:
pp: case inr
α : Type u
β : Type v
inst✝¹ : TopologicalSpace α
inst✝ : TopologicalSpace β
f : α → β
connected_fibers : ∀ (t : β), IsConnected (f ⁻¹' {t})
hcl : IsCoinducing f
t : Set β
ht : IsClosed[inst✝] t
ht' : IsConnected t
hf : Surjective f
hT : IsClosed[inst✝¹] (f ⁻¹' t)
u v : Set α
hu : IsClosed[inst✝¹] u
hv : IsClosed[inst✝¹] v
huv : f ⁻¹' t ⊆ u ∪ v
uv_disj : Disjoint u v
T₁ : Set β := ⋯
T₂ : Set β := ⋯
fiber_decomp : ∀ t' ∈ t, f ⁻¹' {t'} ⊆ u ∨ f ⁻¹' {t'} ⊆ v
T₁_u : f ⁻¹' T₁ = f ⁻¹' t ∩ u
T₂_v : f ⁻¹' T₂ = f ⁻¹' t ∩ v
hT₁ : IsClosed[inst✝] T₁
hT₂ : IsClosed[inst✝] T₂
T_decomp : t ⊆ T₁ ∪ T₂
T_disjoint : Disjoint T₁ T₂
h : t ⊆ T₂
⊢ f ⁻¹' t ⊆ v

Tactic:
Subset.antisymm_iff

Goal state after:
case inr
α : Type u
β : Type v
inst✝¹ : TopologicalSpace α
inst✝ : TopologicalSpace β
f : α → β
connected_fibers : ∀ (t : β), IsConnected (f ⁻¹' {t})
hcl : IsCoinducing f
t : Set β
ht : IsClosed[inst✝] t
ht' : IsConnected t
hf : Surjective f
hT : IsClosed[inst✝¹] (f ⁻¹' t)
u v : Set α
hu : IsClosed[inst✝¹] u
hv : IsClosed[inst✝¹] v
huv : f ⁻¹' t ⊆ u ∪ v
uv_disj : Disjoint u v
T₁ : Set β := {t' | t' ∈ t ∧ f ⁻¹' {t'} ⊆ u}
T₂ : Set β := {t' | t' ∈ t ∧ f ⁻¹' {t'} ⊆ v}
fiber_decomp : ∀ t' ∈ t, f ⁻¹' {t'} ⊆ u ∨ f ⁻¹' {t'} ⊆ v
T₁_u : f ⁻¹' T₁ = f ⁻¹' t ∩ u
T₂_v : f ⁻¹' T₂ ⊆ f ⁻¹' t ∩ v ∧ f ⁻¹' t ∩ v ⊆ f ⁻¹' T₂
hT₁ : IsClosed[inst✝] T₁
hT₂ : IsClosed[inst✝] T₂
T_decomp : t ⊆ T₁ ∪ T₂
T_disjoint : Disjoint T₁ T₂
h : t ⊆ T₂
⊢ f ⁻¹' t ⊆ v
Module: Mathlib.Topology.UniformSpace.Cauchy

Goal state before:
pp: α : Type u
uniformSpace : UniformSpace α
f : Filter α
x : α
hf : Cauchy f
adhs : ClusterPt x f
s : Set (α × α)
hs : s ∈ 𝓤 α
⊢ ∃ t ∈ f, t ×ˢ t ⊆ s ∧ ∃ y, (x, y) ∈ s ∧ y ∈ t

Tactic:
obtain ⟨t, t_mem, ht⟩ : ∃ t ∈ f, t ×ˢ t ⊆ s := (cauchy_iff.1 hf).2 s hs
      use t, t_mem, ht
      exact forall_mem_nonempty_iff_neBot.2 adhs _ (inter_mem_inf (mem_nhds_left x hs) t_mem)

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

Goal state before:
pp: α : Type u
uniformSpace : UniformSpace α
s : Set α
⊢ (∀ (l : Ultrafilter α), Cauchy ↑l → ↑l ≤ 𝓟 s → ∃ x ∈ s, ↑l ≤ 𝓝 x) ↔
    ∀ (l : Ultrafilter α), Cauchy ↑l → s ∈ l → ∃ x ∈ s, ↑l ≤ 𝓝 x

Tactic:
simp only [le_principal_iff, Ultrafilter.mem_coe]

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

Goal state before:
pp: α : Type u_2
β : Type u_3
γ : Type u_4
uγ : UniformSpace γ
f : α → β
g : β → γ
⊢ comap (g ∘ f) uγ = comap f (comap g uγ)

Tactic:
ext1
  simp only [uniformity_comap, Filter.comap_comap, Prod.map_comp_map]

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

Goal state before:
pp: α : Type ua
β : Type ub
γ : Type uc
δ : Type ud
ι : Sort u_1
inst✝³ : UniformSpace α
inst✝² : (𝓤 α).IsCountablyGenerated
inst✝¹ : UniformSpace β
inst✝ : (𝓤 β).IsCountablyGenerated
⊢ (𝓤 (α × β)).IsCountablyGenerated

Tactic:
rw [uniformity_prod]
  infer_instance

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

Goal state before:
pp: α : Type u_1
β : Type u_2
ι : Type u_4
inst✝ : UniformSpace β
F : ι → α → β
s : Set α
p : Filter ι
γ : Type u_5
hf : UniformCauchySeqOnFilter F p (𝓟 s)
g : γ → α
⊢ UniformCauchySeqOnFilter (fun n ↦ F n ∘ g) p (𝓟 (g ⁻¹' s))

Tactic:
simpa only [UniformCauchySeqOn, comap_principal] using hf.comp g

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

Goal state before:
pp: α : Type ua
inst✝ : UniformSpace α
K : Set α
ι : Sort u_2
U : ι → Set α
hK : IsCompact K
hopen : ∀ (i : ι), IsOpen[inst✝.toTopologicalSpace] (U i)
hcover : K ⊆ ⋃ i, U i
x : α
hx : x ∈ K
⊢ ∃ i, ∃ V ∈ 𝓤 α, ball x (V ○ V) ⊆ U i

Tactic:
obtain ⟨i, hi⟩ := mem_iUnion.1 (hcover hx)

Goal state after:
α : Type ua
inst✝ : UniformSpace α
K : Set α
ι : Sort u_2
U : ι → Set α
hK : IsCompact K
hopen : ∀ (i : ι), IsOpen[inst✝.toTopologicalSpace] (U i)
hcover : K ⊆ ⋃ i, U i
x : α
hx : x ∈ K
i : ι
hi : x ∈ U i
⊢ ∃ i, ∃ V ∈ 𝓤 α, ball x (V ○ V) ⊆ U i
Module: Mathlib.Topology.Coherent

Goal state before:
pp: X : Type u_1
inst✝¹ : TopologicalSpace X
S : Set (Set X)
inst✝ : SequentialSpace X
h : ∀ ⦃u : ℕ → X⦄ ⦃x : X⦄, Tendsto u atTop (𝓝 x) → insert x (range u) ∈ S
t : Set X
ht : ∀ s ∈ S, IsClosed[instTopologicalSpaceSubtype] (Subtype.val ⁻¹' t)
u : ℕ → X
x : X
hut : ∀ (n : ℕ), u n ∈ t
hux : Tendsto u atTop (𝓝 x)
s : Set X
hsc : IsClosed[inst✝¹] s
hst : ∀ (x_1 : X), x_1 ∈ insert x (range u) ∩ s ↔ x_1 ∈ insert x (range u) ∩ t
this : x ∈ s
⊢ x ∈ t

Tactic:
by specialize hst x; simp_all

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

Goal state before:
pp: α : Type u_1
β : Type u_2
inst✝¹ : TopologicalSpace α
inst✝ : UniformSpace β
f : α → β
s : Set α
x : α
hx : x ∈ s
L : ∀ u ∈ 𝓤 β, ∃ t ∈ 𝓝[s] x, ∃ F, ContinuousWithinAt F s x ∧ ∀ y ∈ t, (f y, F y) ∈ u
⊢ ContinuousWithinAt f s x

Tactic:
refine Uniform.continuousWithinAt_iff'_left.2 fun u₀ hu₀ => ?_
  obtain ⟨u₁, h₁, u₁₀⟩ : ∃ u ∈ 𝓤 β, u ○ u ⊆ u₀ := comp_mem_uniformity_sets hu₀
  obtain ⟨u₂, h₂, hsymm, u₂₁⟩ : ∃ u ∈ 𝓤 β, (∀ {a b}, (a, b) ∈ u → (b, a) ∈ u) ∧ u ○ u ⊆ u₁ :=
    comp_symm_of_uniformity h₁
  rcases L u₂ h₂ with ⟨t, tx, F, hFc, hF⟩
  have A : ∀ᶠ y in 𝓝[s] x, (f y, F y) ∈ u₂ := Eventually.mono tx hF
  have B : ∀ᶠ y in 𝓝[s] x, (F y, F x) ∈ u₂ := Uniform.continuousWithinAt_iff'_left.1 hFc h₂
  have C : ∀ᶠ y in 𝓝[s] x, (f y, F x) ∈ u₁ :=
    (A.and B).mono fun y hy => u₂₁ (prodMk_mem_comp hy.1 hy.2)
  have : (F x, f x) ∈ u₁ :=
    u₂₁ (prodMk_mem_comp (refl_mem_uniformity h₂) (hsymm (A.self_of_nhdsWithin hx)))
  exact C.mono fun y hy => u₁₀ <| prodMk_mem_comp hy this

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

Goal state before:
pp: α : Type u_1
β : Type u_2
ι : Type u_4
inst✝² : TopologicalSpace α
inst✝¹ : UniformSpace β
F : ι → α → β
f : α → β
p : Filter ι
inst✝ : CompactSpace α
h : TendstoLocallyUniformly F f p
V : Set (β × β)
hV : V ∈ 𝓤 β
U : α → Set α
t : Finset ↑univ
ht : univ ⊆ ⋃ x ∈ t, U ↑x
hU : ∀ᶠ (x : ι) in p, ∀ (i : ↥t), ∀ y ∈ U ↑↑i, (f y, F x y) ∈ V
i : ι
hi : ∀ (i_1 : ↥t), ∀ y ∈ U ↑↑i_1, (f y, F i y) ∈ V
x : α
⊢ (f x, F i x) ∈ V

Tactic:
specialize ht (mem_univ x)

Goal state after:
α : Type u_1
β : Type u_2
ι : Type u_4
inst✝² : TopologicalSpace α
inst✝¹ : UniformSpace β
F : ι → α → β
f : α → β
p : Filter ι
inst✝ : CompactSpace α
h : TendstoLocallyUniformly F f p
V : Set (β × β)
hV : V ∈ 𝓤 β
U : α → Set α
t : Finset ↑univ
hU : ∀ᶠ (x : ι) in p, ∀ (i : ↥t), ∀ y ∈ U ↑↑i, (f y, F x y) ∈ V
i : ι
hi : ∀ (i_1 : ↥t), ∀ y ∈ U ↑↑i_1, (f y, F i y) ∈ V
x : α
ht : x ∈ ⋃ x ∈ t, U ↑x
⊢ (f x, F i x) ∈ V
Module: Mathlib.Topology.UniformSpace.HeineCantor

Goal state before:
pp: case hmono
α : Type u_4
β : Type u_5
E : Type u_6
inst✝² : TopologicalSpace α
inst✝¹ : TopologicalSpace β
inst✝ : UniformSpace E
f : α → β → E
s : Set α
k : Set β
q : α
u : Set (E × E)
hk : IsCompact k
hf : ContinuousOn (Function.uncurry f) (s ×ˢ k)
hq : q ∈ s
hu : u ∈ 𝓤 E
⊢ ∀ ⦃s_1 t : Set β⦄,
    s_1 ⊆ t →
      (∃ v ∈ 𝓝[s] q, ∀ p ∈ v, ∀ x ∈ t, (f p x, f q x) ∈ u) → ∃ v ∈ 𝓝[s] q, ∀ p ∈ v, ∀ x ∈ s_1, (f p x, f q x) ∈ u

pp: case hunion
α : Type u_4
β : Type u_5
E : Type u_6
inst✝² : TopologicalSpace α
inst✝¹ : TopologicalSpace β
inst✝ : UniformSpace E
f : α → β → E
s : Set α
k : Set β
q : α
u : Set (E × E)
hk : IsCompact k
hf : ContinuousOn (Function.uncurry f) (s ×ˢ k)
hq : q ∈ s
hu : u ∈ 𝓤 E
⊢ ∀ ⦃s_1 t : Set β⦄,
    (∃ v ∈ 𝓝[s] q, ∀ p ∈ v, ∀ x ∈ s_1, (f p x, f q x) ∈ u) →
      (∃ v ∈ 𝓝[s] q, ∀ p ∈ v, ∀ x ∈ t, (f p x, f q x) ∈ u) → ∃ v ∈ 𝓝[s] q, ∀ p ∈ v, ∀ x ∈ s_1 ∪ t, (f p x, f q x) ∈ u

pp: case hnhds
α : Type u_4
β : Type u_5
E : Type u_6
inst✝² : TopologicalSpace α
inst✝¹ : TopologicalSpace β
inst✝ : UniformSpace E
f : α → β → E
s : Set α
k : Set β
q : α
u : Set (E × E)
hk : IsCompact k
hf : ContinuousOn (Function.uncurry f) (s ×ˢ k)
hq : q ∈ s
hu : u ∈ 𝓤 E
⊢ ∀ x ∈ k, ∃ t ∈ 𝓝[k] x, ∃ v ∈ 𝓝[s] q, ∀ p ∈ v, ∀ x ∈ t, (f p x, f q x) ∈ u

Tactic:
· intro t' t ht't ⟨v, v_mem, hv⟩
    exact ⟨v, v_mem, fun p hp x hx ↦ hv p hp x (ht't hx)⟩

Goal state after:
case hunion
α : Type u_4
β : Type u_5
E : Type u_6
inst✝² : TopologicalSpace α
inst✝¹ : TopologicalSpace β
inst✝ : UniformSpace E
f : α → β → E
s : Set α
k : Set β
q : α
u : Set (E × E)
hk : IsCompact k
hf : ContinuousOn (Function.uncurry f) (s ×ˢ k)
hq : q ∈ s
hu : u ∈ 𝓤 E
⊢ ∀ ⦃s_1 t : Set β⦄,
    (∃ v ∈ 𝓝[s] q, ∀ p ∈ v, ∀ x ∈ s_1, (f p x, f q x) ∈ u) →
      (∃ v ∈ 𝓝[s] q, ∀ p ∈ v, ∀ x ∈ t, (f p x, f q x) ∈ u) → ∃ v ∈ 𝓝[s] q, ∀ p ∈ v, ∀ x ∈ s_1 ∪ t, (f p x, f q x) ∈ u

case hnhds
α : Type u_4
β : Type u_5
E : Type u_6
inst✝² : TopologicalSpace α
inst✝¹ : TopologicalSpace β
inst✝ : UniformSpace E
f : α → β → E
s : Set α
k : Set β
q : α
u : Set (E × E)
hk : IsCompact k
hf : ContinuousOn (Function.uncurry f) (s ×ˢ k)
hq : q ∈ s
hu : u ∈ 𝓤 E
⊢ ∀ x ∈ k, ∃ t ∈ 𝓝[k] x, ∃ v ∈ 𝓝[s] q, ∀ p ∈ v, ∀ x ∈ t, (f p x, f q x) ∈ u
Module: Mathlib.Topology.Algebra.Group.Basic

Goal state before:
pp: G : Type w
inst✝³ : TopologicalSpace G
inst✝² : Group G
inst✝¹ : IsTopologicalGroup G
inst✝ : FirstCountableTopology G
u : ℕ → Set G
hu : (𝓝 1).HasBasis (fun x ↦ True) u
u_anti : Antitone u
this : ∀ (ib : ℕ), ∃ a b, True ∧ ∀ (a_1 b_1 : G), a_1 ∈ u a → b_1 ∈ u b → a_1 * b_1 ∈ u ib
n j k : ℕ
h : ∀ (a b : G), a ∈ u j → b ∈ u k → a * b ∈ u n
m : ℕ
hm : m ∈ Ici (max j k)
a : G
ha : a ∈ u m
b : G
hb : b ∈ u m
⊢ (fun x1 x2 ↦ x1 * x2) a b ∈ u n

Tactic:
exact h a b (u_anti ((le_max_left _ _).trans hm) ha) (u_anti ((le_max_right _ _).trans hm) hb)

Goal state after:
Module: Mathlib.Topology.Algebra.GroupWithZero

Goal state before:
pp: G₀ : Type u_3
inst✝² : TopologicalSpace G₀
inst✝¹ : GroupWithZero G₀
inst✝ : SeparatelyContinuousMul G₀
a : G₀
ha : a ≠ 0
⊢ map (fun x ↦ x * a) (𝓝 1) = 𝓝 a

Tactic:
map_mul_right_nhds₀ ha,

Goal state after:
G₀ : Type u_3
inst✝² : TopologicalSpace G₀
inst✝¹ : GroupWithZero G₀
inst✝ : SeparatelyContinuousMul G₀
a : G₀
ha : a ≠ 0
⊢ 𝓝 (1 * a) = 𝓝 a
Module: Mathlib.Topology.Algebra.Field

Goal state before:
pp: K : Type u_1
inst✝⁷ : DivisionRing K
inst✝⁶ : TopologicalSpace K
R : Type u_2
inst✝⁵ : DivisionSemiring R
inst✝⁴ : PartialOrder R
inst✝³ : IsStrictOrderedRing R
inst✝² : PosMulReflectLT R
inst✝¹ : TopologicalSpace R
inst✝ : ContinuousInv₀ R
this : Continuous fun x ↦ (↑x)⁻¹
⊢ Continuous fun x ↦ ↑((unitsEquivPos R).invFun x)⁻¹

Tactic:
simpa [Topology.IsEmbedding.subtypeVal.continuous_iff, Function.comp_def]

Goal state after:
Module: Mathlib.Order.OrdContinuous

Goal state before:
pp: α : Type u
β : Type v
inst✝¹ : SemilatticeSup α
inst✝ : SemilatticeSup β
f : α → β
hf : LeftOrdContinuous f
h : Injective f
x y : α
⊢ f x ≤ f y ↔ x ≤ y

Tactic:
by
  simp only [← sup_eq_right, ← hf.map_sup, h.eq_iff]

Goal state after:
Module: Mathlib.Topology.Algebra.IsUniformGroup.Basic

Goal state before:
pp: α : Type u_1
β : Type u_2
γ : Type u_3
δ : Type u_4
G : Type u_5
inst✝¹⁴ : TopologicalSpace α
inst✝¹³ : AddCommGroup α
inst✝¹² : IsTopologicalAddGroup α
inst✝¹¹ : TopologicalSpace β
inst✝¹⁰ : AddCommGroup β
inst✝⁹ : TopologicalSpace γ
inst✝⁸ : AddCommGroup γ
inst✝⁷ : IsTopologicalAddGroup γ
inst✝⁶ : TopologicalSpace δ
inst✝⁵ : AddCommGroup δ
inst✝⁴ : UniformSpace G
inst✝³ : AddCommGroup G
e : β →+ α
de : IsDenseInducing ⇑e
f : δ →+ γ
df : IsDenseInducing ⇑f
φ : β →+ δ →+ G
hφ : Continuous[instTopologicalSpaceProd, inst✝⁴.toTopologicalSpace] fun p ↦ (φ p.1) p.2
inst✝² : IsUniformAddGroup G
inst✝¹ : T0Space G
inst✝ : CompleteSpace G
x₀ : α
y₀ : γ
this :
  map (fun p ↦ (fun p ↦ (φ p.1) p.2) p.2 - (fun p ↦ (φ p.1) p.2) p.1)
      (comap (fun p ↦ ((e p.1.1, f p.1.2), e p.2.1, f p.2.2)) (𝓝 (x₀, y₀) ×ˢ 𝓝 (x₀, y₀))) ≤
    𝓝 0
⊢ map (fun p ↦ (φ p.1) p.2) (comap (Prod.map ⇑e ⇑f) (𝓝 (x₀, y₀))) ×ˢ
      map (fun p ↦ (φ p.1) p.2) (comap (Prod.map ⇑e ⇑f) (𝓝 (x₀, y₀))) ≤
    𝓤 G

Tactic:
by
      rwa [uniformity_eq_comap_nhds_zero G, prod_map_map_eq, ← map_le_iff_le_comap, Filter.map_map,
        prod_comap_comap_eq]

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

Goal state before:
pp: α : Type u_1
inst✝³ : TopologicalSpace α
inst✝² : LinearOrder α
inst✝¹ : OrderTopology α
inst✝ : SecondCountableTopology α
s : Set α
t : Set α := {x | x ∈ s ∧ 𝓝[s ∩ Ioi x] x = ⊥ ∧ ¬IsTop x}
H : t.Countable
⊢ {x | x ∈ s ∧ 𝓝[s ∩ Ioi x] x = ⊥}.Countable

Tactic:
have : { x ∈ s | 𝓝[s ∩ Ioi x] x = ⊥ } ⊆ t ∪ {x | IsTop x} := by
      intro x hx
      by_cases h'x : IsTop x
      · simp [h'x]
      · simpa [-sep_and, t, h'x]
    apply Countable.mono this
    simp [H, (subsingleton_isTop α).countable]

Goal state after:
Module: Mathlib.Topology.Instances.AddCircle.Defs

Goal state before:
pp: 𝕜 : Type u_1
inst✝⁵ : AddCommGroup 𝕜
inst✝⁴ : LinearOrder 𝕜
inst✝³ : IsOrderedAddMonoid 𝕜
inst✝² : Archimedean 𝕜
inst✝¹ : TopologicalSpace 𝕜
inst✝ : OrderTopology 𝕜
p : 𝕜
hp : 0 < p
a x : 𝕜
hx : ¬x ≡ a [PMOD p]
⊢ toIcoDiv hp a =ᶠ[𝓝 x] fun x_1 ↦ toIcoDiv hp a x

Tactic:
← nhdsLT_sup_nhdsGE,

Goal state after:
𝕜 : Type u_1
inst✝⁵ : AddCommGroup 𝕜
inst✝⁴ : LinearOrder 𝕜
inst✝³ : IsOrderedAddMonoid 𝕜
inst✝² : Archimedean 𝕜
inst✝¹ : TopologicalSpace 𝕜
inst✝ : OrderTopology 𝕜
p : 𝕜
hp : 0 < p
a x : 𝕜
hx : ¬x ≡ a [PMOD p]
⊢ toIcoDiv hp a =ᶠ[𝓝[<] x ⊔ 𝓝[≥] x] fun x_1 ↦ toIcoDiv hp a x
Module: Mathlib.Algebra.Category.Grp.IsFinite

Goal state before:
pp: M N : AddCommGrpCat
f : M ⟶ N
hf : Epi f
hM : M.isFinite
⊢ N.isFinite

Tactic:
rw [AddCommGrpCat.epi_iff_surjective] at hf

Goal state after:
M N : AddCommGrpCat
f : M ⟶ N
hf : Function.Surjective ⇑(ConcreteCategory.hom f)
hM : M.isFinite
⊢ N.isFinite
Module: Mathlib.Algebra.Category.Grp.LargeColimits

Goal state before:
pp: case h
J : Type u
inst✝¹ : Category.{v, u} J
F : J ⥤ AddCommGrpCat
c : Cocone F
inst✝ : DecidableEq J
x✝ : Nonempty (IsColimit c)
hc : IsColimit c
χ : CharacterModule (Colimits.Quot F)
c' : Cocone F :=
  { pt := of (ULift.{w, 0} (AddCircle 1)),
    ι := { app := fun j ↦ ofHom ((AddEquiv.ulift.symm.toAddMonoidHom.comp χ).comp (Quot.ι F j)), naturality := ⋯ } }
j : J
x : ↑(F.obj j)
⊢ AddEquiv.ulift ((ConcreteCategory.hom (c.ι.app j ≫ hc.desc c')) x) = χ ((Quot.ι F j) x)

Tactic:
hc.fac

Goal state after:
case h
J : Type u
inst✝¹ : Category.{v, u} J
F : J ⥤ AddCommGrpCat
c : Cocone F
inst✝ : DecidableEq J
x✝ : Nonempty (IsColimit c)
hc : IsColimit c
χ : CharacterModule (Colimits.Quot F)
c' : Cocone F :=
  { pt := of (ULift.{w, 0} (AddCircle 1)),
    ι := { app := fun j ↦ ofHom ((AddEquiv.ulift.symm.toAddMonoidHom.comp χ).comp (Quot.ι F j)), naturality := ⋯ } }
j : J
x : ↑(F.obj j)
⊢ AddEquiv.ulift ((ConcreteCategory.hom (c'.ι.app j)) x) = χ ((Quot.ι F j) x)
Module: Mathlib.Topology.Instances.AddCircle.Defs

Goal state before:
pp: 𝕜 : Type u_1
inst✝³ : AddCommGroup 𝕜
p : 𝕜
inst✝² : LinearOrder 𝕜
inst✝¹ : IsOrderedAddMonoid 𝕜
hp : Fact (0 < p)
a : 𝕜
inst✝ : Archimedean 𝕜
ha : a ∈ Ico 0 p
⊢ ↑a = 0 ↔ a = 0

Tactic:
by
  have h0 : 0 ∈ Ico 0 (0 + p) := by simpa [zero_add, left_mem_Ico] using hp.out
  have ha' : a ∈ Ico 0 (0 + p) := by rwa [zero_add]
  rw [← AddCircle.coe_eq_coe_iff_of_mem_Ico ha' h0, QuotientAddGroup.mk_zero]

Goal state after:
Module: Mathlib.Algebra.Category.ModuleCat.Subobject

Goal state before:
pp: R : Type u
inst✝ : Ring R
M : ModuleCat R
S T : Submodule R ↑M
⊢ { toFun := fun N ↦ mk (↟N.subtype), invFun := fun S ↦ (Hom.hom S.arrow).range, left_inv := ⋯, right_inv := ⋯ } S ≤
      { toFun := fun N ↦ mk (↟N.subtype), invFun := fun S ↦ (Hom.hom S.arrow).range, left_inv := ⋯, right_inv := ⋯ } T ↔
    S ≤ T

Tactic:
refine ⟨fun h => ?_, fun h => mk_le_mk_of_comm (↟(Submodule.inclusion h)) rfl⟩
        convert! LinearMap.range_comp_le_range (ofMkLEMk _ _ h).hom (ofHom T.subtype).hom
        · rw [← hom_comp, ofMkLEMk_comp]
          exact (Submodule.range_subtype _).symm
        · exact (Submodule.range_subtype _).symm

Goal state after:
Module: Mathlib.CategoryTheory.Abelian.Refinements

Goal state before:
pp: case mp
C : Type u_1
inst✝¹ : Category.{v_1, u_1} C
inst✝ : Abelian C
S : ShortComplex C
hS : ∀ ⦃A : C⦄ (y : A ⟶ S.cycles), ∃ A' π, ∃ (_ : Epi π), ∃ x, π ≫ y = x ≫ S.toCycles
A : C
a : A ⟶ S.X₂
ha : a ≫ S.g = 0
A' : C
π : A' ⟶ A
hπ : Epi π
x₁ : A' ⟶ S.X₁
fac : π ≫ S.liftCycles a ha = x₁ ≫ S.toCycles
⊢ ∃ A' π, ∃ (_ : Epi π), ∃ x₁, π ≫ a = x₁ ≫ S.f

Tactic:
exact ⟨A', π, hπ, x₁, by simpa only [assoc, liftCycles_i, toCycles_i] using fac =≫ S.iCycles⟩

Goal state after:
Module: Mathlib.Algebra.Category.ModuleCat.Adjunctions

Goal state before:
pp: R : Type u
inst✝ : Ring R
X : Type u
M : ModuleCat R
⊢ (adj R).homEquiv X M = freeHomEquiv

Tactic:
by
  simp only [adj, Adjunction.mkOfHomEquiv_homEquiv]

Goal state after:
Module: Mathlib.CategoryTheory.Limits.Shapes.Multiequalizer

Goal state before:
pp: J : MulticospanShape
C : Type u_1
inst✝ : Category.{v_1, u_1} C
F G : WalkingMulticospan J ⥤ C
left : (i : J.L) → F.obj (WalkingMulticospan.left i) ≅ G.obj (WalkingMulticospan.left i)
right : (i : J.R) → F.obj (WalkingMulticospan.right i) ≅ G.obj (WalkingMulticospan.right i)
wl : ∀ (i : J.R), F.map (Hom.fst i) ≫ (right i).hom = (left (J.fst i)).hom ≫ G.map (Hom.fst i)
wr : ∀ (i : J.R), F.map (Hom.snd i) ≫ (right i).hom = (left (J.snd i)).hom ≫ G.map (Hom.snd i)
⊢ ∀ {X Y : WalkingMulticospan J} (f : X ⟶ Y),
    F.map f ≫
        (match Y with
          | WalkingMulticospan.left i => left i
          | WalkingMulticospan.right i => right i).hom =
      (match X with
          | WalkingMulticospan.left i => left i
          | WalkingMulticospan.right i => right i).hom ≫
        G.map f

Tactic:
rintro _ _ ⟨_⟩ <;> simp [wl, wr]

Goal state after: