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

Goal state before:
pp: α : Type u
inst✝ : TopologicalSpace α
x : α
h : connectedComponent x = univ
⊢ IsPreconnected (connectedComponent x)

Tactic:
]

Goal state after:
α : Type u
inst✝ : TopologicalSpace α
x : α
h : connectedComponent x = univ
⊢ IsPreconnected (connectedComponent x)
Module: Mathlib.Topology.Separation.Regular

Goal state before:
pp: case refine_2
X : Type u_1
Y : Type u_2
inst✝² : TopologicalSpace X
inst✝¹ : TopologicalSpace Y
inst✝ : CompletelyNormalSpace Y
e : X → Y
he : IsInducing e
s t : Set X
hd₁ : Disjoint (closure[inst✝²] s) t
hd₂ : Disjoint s (closure[inst✝²] t)
⊢ Disjoint s (closure[inst✝²] t)

Tactic:
]

Goal state after:
case refine_2
X : Type u_1
Y : Type u_2
inst✝² : TopologicalSpace X
inst✝¹ : TopologicalSpace Y
inst✝ : CompletelyNormalSpace Y
e : X → Y
he : IsInducing e
s t : Set X
hd₁ : Disjoint (closure[inst✝²] s) t
hd₂ : Disjoint s (closure[inst✝²] t)
⊢ Disjoint s (closure[inst✝²] t)
Module: Mathlib.Topology.Connected.Basic

Goal state before:
pp: α : Type u
inst✝ : TopologicalSpace α
h : ∀ (x : α), connectedComponent x = univ
hα : IsEmpty α
⊢ IsPreconnected ∅

Tactic:
]

Goal state after:
α : Type u
inst✝ : TopologicalSpace α
h : ∀ (x : α), connectedComponent x = univ
hα : IsEmpty α
⊢ IsPreconnected ∅
Module: Mathlib.Topology.Connected.Basic

Goal state before:
pp: α : Type u
inst✝ : TopologicalSpace α
h : ∀ (x : α), connectedComponent x = univ
hα : Nonempty α
⊢ IsPreconnected (connectedComponent (Classical.choice hα))

Tactic:
]

Goal state after:
α : Type u
inst✝ : TopologicalSpace α
h : ∀ (x : α), connectedComponent x = univ
hα : Nonempty α
⊢ IsPreconnected (connectedComponent (Classical.choice hα))
Module: Mathlib.Topology.Separation.Regular

Goal state before:
pp: X : Type u_1
inst✝ : TopologicalSpace X
s t : Set X
hSt : Disjoint (closure[inst✝] s) t
hsT : Disjoint s (closure[inst✝] t)
e : Set X := (closure[inst✝] s ∩ closure[inst✝] t)ᶜ
h : NormalSpace ↑e
he : IsOpen[inst✝] e
⊢ ∀ ⦃a : { x // x ∈ e }⦄, a ∈ Subtype.val ⁻¹' closure[inst✝] s → a ∉ Subtype.val ⁻¹' closure[inst✝] t

Tactic:
]

Goal state after:
X : Type u_1
inst✝ : TopologicalSpace X
s t : Set X
hSt : Disjoint (closure[inst✝] s) t
hsT : Disjoint s (closure[inst✝] t)
e : Set X := (closure[inst✝] s ∩ closure[inst✝] t)ᶜ
h : NormalSpace ↑e
he : IsOpen[inst✝] e
⊢ ∀ ⦃a : { x // x ∈ e }⦄, a ∈ Subtype.val ⁻¹' closure[inst✝] s → a ∉ Subtype.val ⁻¹' closure[inst✝] t
Module: Mathlib.Topology.Connected.Clopen

Goal state before:
pp: X : Type u_3
inst✝ : TopologicalSpace X
u v : Set X
hu : IsClopen (v ↓∩ u)
huv₁ : u ⊆ v
this : u = ⋃ i, ⋃ (x : i ∈ v), ⋃ (_ : i ∈ u), Subtype.val '' connectedComponent ⟨i, ⋯⟩
⊢ ⋃ i, ⋃ (x : i ∈ v), ⋃ (_ : i ∈ u), Subtype.val '' connectedComponent ⟨i, ⋯⟩ = ⋃ x ∈ u, connectedComponentIn v x

Tactic:
]

Goal state after:
X : Type u_3
inst✝ : TopologicalSpace X
u v : Set X
hu : IsClopen (v ↓∩ u)
huv₁ : u ⊆ v
this : u = ⋃ i, ⋃ (x : i ∈ v), ⋃ (_ : i ∈ u), Subtype.val '' connectedComponent ⟨i, ⋯⟩
⊢ ⋃ i, ⋃ (x : i ∈ v), ⋃ (_ : i ∈ u), Subtype.val '' connectedComponent ⟨i, ⋯⟩ = ⋃ x ∈ u, connectedComponentIn v x
Module: Mathlib.Topology.Connected.Basic

Goal state before:
pp: α : Type u
β : Type v
ι : Type u_1
X : ι → Type u_2
inst✝³ : TopologicalSpace α
s t u v : Set α
inst✝² : TopologicalSpace β
inst✝¹ : PreconnectedSpace α
inst✝ : PreconnectedSpace β
⊢ IsPreconnected (univ ×ˢ univ)

Tactic:
]

Goal state after:
α : Type u
β : Type v
ι : Type u_1
X : ι → Type u_2
inst✝³ : TopologicalSpace α
s t u v : Set α
inst✝² : TopologicalSpace β
inst✝¹ : PreconnectedSpace α
inst✝ : PreconnectedSpace β
⊢ IsPreconnected (univ ×ˢ univ)
Module: Mathlib.Topology.Connected.Basic

Goal state before:
pp: α : Type u
β : Type v
ι : Type u_1
X : ι → Type u_2
inst✝² : TopologicalSpace α
s t u v : Set α
inst✝¹ : (i : ι) → TopologicalSpace (X i)
inst✝ : ∀ (i : ι), PreconnectedSpace (X i)
⊢ IsPreconnected (univ.pi fun i ↦ univ)

Tactic:
]

Goal state after:
α : Type u
β : Type v
ι : Type u_1
X : ι → Type u_2
inst✝² : TopologicalSpace α
s t u v : Set α
inst✝¹ : (i : ι) → TopologicalSpace (X i)
inst✝ : ∀ (i : ι), PreconnectedSpace (X i)
⊢ IsPreconnected (univ.pi fun i ↦ univ)
Module: Mathlib.Topology.Connected.Basic

Goal state before:
pp: α : Type u
inst✝ : TopologicalSpace α
s : Set α
h : IsPreconnected s
⊢ IsPreconnected s

Tactic:
]

Goal state after:
α : Type u
inst✝ : TopologicalSpace α
s : Set α
h : IsPreconnected s
⊢ IsPreconnected s
Module: Mathlib.Topology.Compactness.Lindelof

Goal state before:
pp: case mp.refine_1
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 → ι
h₁ : IsLindelof (⋃ i, (b ∘ f') i)
h₂ : IsOpen[inst✝] (⋃ i, (b ∘ f') i)
hf' : ∀ (i : Y), b (f' i) = (b ∘ f') i
t : Set Y
ht : t.Countable ∧ ⋃ i, (b ∘ f') i ⊆ ⋃ i ∈ t, (b ∘ f') i
i : Y
hi : i ∈ t
⊢ (b ∘ f') i ⊆ ⋃ x, b ↑x

Tactic:
]

Goal state after:
case mp.refine_1
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 → ι
h₁ : IsLindelof (⋃ i, (b ∘ f') i)
h₂ : IsOpen[inst✝] (⋃ i, (b ∘ f') i)
hf' : ∀ (i : Y), b (f' i) = (b ∘ f') i
t : Set Y
ht : t.Countable ∧ ⋃ i, (b ∘ f') i ⊆ ⋃ i ∈ t, (b ∘ f') i
i : Y
hi : i ∈ t
⊢ (b ∘ f') i ⊆ ⋃ x, b ↑x
Module: Mathlib.Topology.Connected.Clopen

Goal state before:
pp: 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), IsClosed[inst✝¹] u → IsClosed[inst✝¹] v → f ⁻¹' t ⊆ u ∪ v → Disjoint u v → f ⁻¹' t ⊆ u ∨ f ⁻¹' t ⊆ v

Tactic:
]

Goal state after:
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), IsClosed[inst✝¹] u → IsClosed[inst✝¹] v → f ⁻¹' t ⊆ u ∪ v → Disjoint u v → f ⁻¹' t ⊆ u ∨ f ⁻¹' t ⊆ v
Module: Mathlib.Topology.Separation.Regular

Goal state before:
pp: X : Type u_1
inst✝ : TopologicalSpace X
s t : Set X
hSt : Disjoint (closure[inst✝] s) t
hsT : Disjoint s (closure[inst✝] t)
e : Set X := (closure[inst✝] s ∩ closure[inst✝] t)ᶜ
h : NormalSpace ↑e
he : IsOpen[inst✝] e
hst : Disjoint (Subtype.val ⁻¹' closure[inst✝] s) (Subtype.val ⁻¹' closure[inst✝] t)
U V : Set { x // x ∈ e }
hU : ∃ t, IsOpen[inst✝] t ∧ Subtype.val ⁻¹' t = U
hV : ∃ t, IsOpen[inst✝] t ∧ Subtype.val ⁻¹' t = V
hsU : Subtype.val ⁻¹' closure[inst✝] s ⊆ U
htV : Subtype.val ⁻¹' closure[inst✝] t ⊆ V
hUV : Disjoint U V
⊢ Disjoint (𝓝ˢ s) (𝓝ˢ t)

Tactic:
]

Goal state after:
X : Type u_1
inst✝ : TopologicalSpace X
s t : Set X
hSt : Disjoint (closure[inst✝] s) t
hsT : Disjoint s (closure[inst✝] t)
e : Set X := (closure[inst✝] s ∩ closure[inst✝] t)ᶜ
h : NormalSpace ↑e
he : IsOpen[inst✝] e
hst : Disjoint (Subtype.val ⁻¹' closure[inst✝] s) (Subtype.val ⁻¹' closure[inst✝] t)
U V : Set { x // x ∈ e }
hU : ∃ t, IsOpen[inst✝] t ∧ Subtype.val ⁻¹' t = U
hV : ∃ t, IsOpen[inst✝] t ∧ Subtype.val ⁻¹' t = V
hsU : Subtype.val ⁻¹' closure[inst✝] s ⊆ U
htV : Subtype.val ⁻¹' closure[inst✝] t ⊆ V
hUV : Disjoint U V
⊢ Disjoint (𝓝ˢ s) (𝓝ˢ t)
Module: Mathlib.Topology.DenseEmbedding

Goal state before:
pp: α : Type u_1
β : Type u_2
inst✝¹ : TopologicalSpace α
inst✝ : TopologicalSpace β
i : α → β
s : Set α
a : α
di : IsDenseInducing i
hs : ∃ i_1, (i a ∈ i_1 ∧ IsOpen[inst✝] i_1) ∧ i ⁻¹' i_1 ⊆ s
⊢ closure[inst✝] (i '' s) ∈ 𝓝 (i a)

Tactic:
]

Goal state after:
α : Type u_1
β : Type u_2
inst✝¹ : TopologicalSpace α
inst✝ : TopologicalSpace β
i : α → β
s : Set α
a : α
di : IsDenseInducing i
hs : ∃ i_1, (i a ∈ i_1 ∧ IsOpen[inst✝] i_1) ∧ i ⁻¹' i_1 ⊆ s
⊢ closure[inst✝] (i '' s) ∈ 𝓝 (i a)
Module: Mathlib.Topology.DenseEmbedding

Goal state before:
pp: α : Type u_1
β : Type u_2
inst✝¹ : TopologicalSpace α
inst✝ : TopologicalSpace β
i : α → β
di : IsDenseInducing i
s : Set α
H : Dense (i '' s)
x : α
⊢ x ∈ univ

Tactic:
]

Goal state after:
α : Type u_1
β : Type u_2
inst✝¹ : TopologicalSpace α
inst✝ : TopologicalSpace β
i : α → β
di : IsDenseInducing i
s : Set α
H : Dense (i '' s)
x : α
⊢ x ∈ univ
Module: Mathlib.Topology.DenseEmbedding

Goal state before:
pp: α : Type u_1
β : Type u_2
inst✝² : TopologicalSpace α
inst✝¹ : TopologicalSpace β
i : α → β
inst✝ : T2Space β
di : IsDenseInducing i
hd : Dense (range i)ᶜ
s : Set α
hs : IsCompact s
x : α
hx : s ∈ 𝓝 x
⊢ False

Tactic:
]

Goal state after:
α : Type u_1
β : Type u_2
inst✝² : TopologicalSpace α
inst✝¹ : TopologicalSpace β
i : α → β
inst✝ : T2Space β
di : IsDenseInducing i
hd : Dense (range i)ᶜ
s : Set α
hs : IsCompact s
x : α
hx : s ∈ 𝓝 x
⊢ False
Module: Mathlib.Topology.DenseEmbedding

Goal state before:
pp: α : Type u_1
β : Type u_2
inst✝² : TopologicalSpace α
inst✝¹ : TopologicalSpace β
i : α → β
inst✝ : T2Space β
di : IsDenseInducing i
hd : Dense (range i)ᶜ
s : Set α
hs : IsCompact s
x : α
hx : s ∈ 𝓝 x
this : i '' s ∈ 𝓝 (i x)
⊢ False

Tactic:
]

Goal state after:
α : Type u_1
β : Type u_2
inst✝² : TopologicalSpace α
inst✝¹ : TopologicalSpace β
i : α → β
inst✝ : T2Space β
di : IsDenseInducing i
hd : Dense (range i)ᶜ
s : Set α
hs : IsCompact s
x : α
hx : s ∈ 𝓝 x
this : i '' s ∈ 𝓝 (i x)
⊢ False
Module: Mathlib.Topology.DenseEmbedding

Goal state before:
pp: α : Type u_1
β : Type u_2
γ : Type u_3
δ : Type u_4
inst✝² : TopologicalSpace α
inst✝¹ : TopologicalSpace β
i : α → β
inst✝ : TopologicalSpace δ
f : γ → α
g : γ → δ
h : δ → β
d : δ
a : α
di : IsDenseInducing i
H : Tendsto h (𝓝 d) (𝓝 (i a))
comm : h ∘ g = i ∘ f
lim1 : map f (comap g (𝓝 d)) ≤ comap i (map h (𝓝 d))
⊢ Tendsto f (comap g (𝓝 d)) (𝓝 a)

Tactic:
]

Goal state after:
α : Type u_1
β : Type u_2
γ : Type u_3
δ : Type u_4
inst✝² : TopologicalSpace α
inst✝¹ : TopologicalSpace β
i : α → β
inst✝ : TopologicalSpace δ
f : γ → α
g : γ → δ
h : δ → β
d : δ
a : α
di : IsDenseInducing i
H : Tendsto h (𝓝 d) (𝓝 (i a))
comm : h ∘ g = i ∘ f
lim1 : map f (comap g (𝓝 d)) ≤ comap i (map h (𝓝 d))
⊢ Tendsto f (comap g (𝓝 d)) (𝓝 a)
Module: Mathlib.Topology.DenseEmbedding

Goal state before:
pp: α : Type u_1
β : Type u_2
γ : Type u_3
δ : Type u_4
inst✝² : TopologicalSpace α
inst✝¹ : TopologicalSpace β
i : α → β
inst✝ : TopologicalSpace δ
f : γ → α
g : γ → δ
h : δ → β
d : δ
a : α
di : IsDenseInducing i
H : Tendsto h (𝓝 d) (𝓝 (i a))
comm : h ∘ g = i ∘ f
lim1 : map f (comap g (𝓝 d)) ≤ comap i (map h (𝓝 d))
⊢ Tendsto f (comap g (𝓝 d)) (𝓝 a)

Tactic:
have lim2 : comap i (map h (𝓝 d)) ≤ comap i (𝓝 (i a)) := comap_mono H

Goal state after:
α : Type u_1
β : Type u_2
γ : Type u_3
δ : Type u_4
inst✝² : TopologicalSpace α
inst✝¹ : TopologicalSpace β
i : α → β
inst✝ : TopologicalSpace δ
f : γ → α
g : γ → δ
h : δ → β
d : δ
a : α
di : IsDenseInducing i
H : Tendsto h (𝓝 d) (𝓝 (i a))
comm : h ∘ g = i ∘ f
lim1 : map f (comap g (𝓝 d)) ≤ comap i (map h (𝓝 d))
lim2 : comap i (map h (𝓝 d)) ≤ comap i (𝓝 (i a))
⊢ Tendsto f (comap g (𝓝 d)) (𝓝 a)
Module: Mathlib.Topology.DenseEmbedding

Goal state before:
pp: α : Type u_1
β : Type u_2
γ : Type u_3
δ : Type u_4
inst✝² : TopologicalSpace α
inst✝¹ : TopologicalSpace β
i : α → β
inst✝ : TopologicalSpace δ
f : γ → α
g : γ → δ
h : δ → β
d : δ
a : α
di : IsDenseInducing i
H : Tendsto h (𝓝 d) (𝓝 (i a))
comm : h ∘ g = i ∘ f
lim1 : map f (comap g (𝓝 d)) ≤ comap i (map h (𝓝 d))
lim2 : comap i (map h (𝓝 d)) ≤ 𝓝 a
⊢ Tendsto f (comap g (𝓝 d)) (𝓝 a)

Tactic:
]

Goal state after:
α : Type u_1
β : Type u_2
γ : Type u_3
δ : Type u_4
inst✝² : TopologicalSpace α
inst✝¹ : TopologicalSpace β
i : α → β
inst✝ : TopologicalSpace δ
f : γ → α
g : γ → δ
h : δ → β
d : δ
a : α
di : IsDenseInducing i
H : Tendsto h (𝓝 d) (𝓝 (i a))
comm : h ∘ g = i ∘ f
lim1 : map f (comap g (𝓝 d)) ≤ comap i (map h (𝓝 d))
lim2 : comap i (map h (𝓝 d)) ≤ 𝓝 a
⊢ Tendsto f (comap g (𝓝 d)) (𝓝 a)
Module: Mathlib.Topology.Separation.Regular

Goal state before:
pp: X : Type u_1
inst✝ : TopologicalSpace X
s t : Set X
hSt : Disjoint (closure[inst✝] s) t
hsT : Disjoint s (closure[inst✝] t)
e : Set X := (closure[inst✝] s ∩ closure[inst✝] t)ᶜ
h : NormalSpace ↑e
he : IsOpen[inst✝] e
hst : Disjoint (Subtype.val ⁻¹' closure[inst✝] s) (Subtype.val ⁻¹' closure[inst✝] t)
U : Set X
hU : IsOpen[inst✝] U
hsU : Subtype.val ⁻¹' closure[inst✝] s ⊆ Subtype.val ⁻¹' U
V : Set X
hV : IsOpen[inst✝] V
htV : Subtype.val ⁻¹' closure[inst✝] t ⊆ Subtype.val ⁻¹' V
hUV : Disjoint (Subtype.val ⁻¹' U) (Subtype.val ⁻¹' V)
⊢ SeparatedNhds s t

Tactic:
]

Goal state after:
X : Type u_1
inst✝ : TopologicalSpace X
s t : Set X
hSt : Disjoint (closure[inst✝] s) t
hsT : Disjoint s (closure[inst✝] t)
e : Set X := (closure[inst✝] s ∩ closure[inst✝] t)ᶜ
h : NormalSpace ↑e
he : IsOpen[inst✝] e
hst : Disjoint (Subtype.val ⁻¹' closure[inst✝] s) (Subtype.val ⁻¹' closure[inst✝] t)
U : Set X
hU : IsOpen[inst✝] U
hsU : Subtype.val ⁻¹' closure[inst✝] s ⊆ Subtype.val ⁻¹' U
V : Set X
hV : IsOpen[inst✝] V
htV : Subtype.val ⁻¹' closure[inst✝] t ⊆ Subtype.val ⁻¹' V
hUV : Disjoint (Subtype.val ⁻¹' U) (Subtype.val ⁻¹' V)
⊢ SeparatedNhds s t
Module: Mathlib.Topology.DenseEmbedding

Goal state before:
pp: α : Type u_1
β : Type u_2
γ : Type u_3
inst✝² : TopologicalSpace α
inst✝¹ : TopologicalSpace β
i : α → β
inst✝ : TopologicalSpace γ
di : IsDenseInducing i
f : α → γ
a : α
hf : ContinuousAt f a
⊢ Tendsto f (𝓝 a) (𝓝 ((𝓝 a).limUnder f))

Tactic:
]

Goal state after:
α : Type u_1
β : Type u_2
γ : Type u_3
inst✝² : TopologicalSpace α
inst✝¹ : TopologicalSpace β
i : α → β
inst✝ : TopologicalSpace γ
di : IsDenseInducing i
f : α → γ
a : α
hf : ContinuousAt f a
⊢ Tendsto f (𝓝 a) (𝓝 ((𝓝 a).limUnder f))
Module: Mathlib.Topology.Connected.Clopen

Goal state before:
pp: case a
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}
t' : β
ht' : t' ∈ t
⊢ ∅ = ∅

Tactic:
]

Goal state after:
Module: Mathlib.Topology.DenseEmbedding

Goal state before:
pp: α : Type u_1
β : Type u_2
γ : Type u_3
inst✝³ : TopologicalSpace α
inst✝² : TopologicalSpace β
i : α → β
inst✝¹ : TopologicalSpace γ
inst✝ : T2Space γ
f : α → γ
di : IsDenseInducing i
hf : ∀ (b : β), ∃ c, Tendsto f (comap i (𝓝 b)) (𝓝 c)
a : α
b : γ
hb : Tendsto f (𝓝 a) (𝓝 b)
⊢ Tendsto f (𝓝 a) (𝓝 b)

Tactic:
]

Goal state after:
α : Type u_1
β : Type u_2
γ : Type u_3
inst✝³ : TopologicalSpace α
inst✝² : TopologicalSpace β
i : α → β
inst✝¹ : TopologicalSpace γ
inst✝ : T2Space γ
f : α → γ
di : IsDenseInducing i
hf : ∀ (b : β), ∃ c, Tendsto f (comap i (𝓝 b)) (𝓝 c)
a : α
b : γ
hb : Tendsto f (𝓝 a) (𝓝 b)
⊢ Tendsto f (𝓝 a) (𝓝 b)
Module: Mathlib.Topology.Separation.Regular

Goal state before:
pp: X : Type u_1
inst✝ : TopologicalSpace X
s t : Set X
hSt : Disjoint (closure[inst✝] s) t
hsT : Disjoint s (closure[inst✝] t)
e : Set X := (closure[inst✝] s ∩ closure[inst✝] t)ᶜ
h : NormalSpace ↑e
he : IsOpen[inst✝] e
hst : Disjoint (Subtype.val ⁻¹' closure[inst✝] s) (Subtype.val ⁻¹' closure[inst✝] t)
U : Set X
hU : IsOpen[inst✝] U
hsU : closure[inst✝] s ∩ e ⊆ U ∩ e
V : Set X
hV : IsOpen[inst✝] V
htV : closure[inst✝] t ∩ e ⊆ V ∩ e
hUV : Disjoint (Subtype.val ⁻¹' U) (Subtype.val ⁻¹' V)
⊢ SeparatedNhds s t

Tactic:
]

Goal state after:
X : Type u_1
inst✝ : TopologicalSpace X
s t : Set X
hSt : Disjoint (closure[inst✝] s) t
hsT : Disjoint s (closure[inst✝] t)
e : Set X := (closure[inst✝] s ∩ closure[inst✝] t)ᶜ
h : NormalSpace ↑e
he : IsOpen[inst✝] e
hst : Disjoint (Subtype.val ⁻¹' closure[inst✝] s) (Subtype.val ⁻¹' closure[inst✝] t)
U : Set X
hU : IsOpen[inst✝] U
hsU : closure[inst✝] s ∩ e ⊆ U ∩ e
V : Set X
hV : IsOpen[inst✝] V
htV : closure[inst✝] t ∩ e ⊆ V ∩ e
hUV : Disjoint (Subtype.val ⁻¹' U) (Subtype.val ⁻¹' V)
⊢ SeparatedNhds s t
Module: Mathlib.Topology.DenseEmbedding

Goal state before:
pp: α : Type u_1
β : Type u_2
γ : Type u_3
inst✝³ : TopologicalSpace α
inst✝² : TopologicalSpace β
i : α → β
inst✝¹ : TopologicalSpace γ
inst✝ : T3Space γ
b : β
f : α → γ
di : IsDenseInducing i
hf : ∀ᶠ (x : β) in 𝓝 b, ∃ c, Tendsto f (comap i (𝓝 x)) (𝓝 c)
φ : β → γ := di.extend f
this✝ : ∀ (b : β), (comap i (𝓝 b)).NeBot
this : ∀ V' ∈ 𝓝 (φ b), IsClosed[inst✝¹] V' → φ ⁻¹' V' ∈ 𝓝 b
⊢ ContinuousAt φ b

Tactic:
simpa [ContinuousAt, (closed_nhds_basis (φ b)).tendsto_right_iff]

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

Goal state before:
pp: case a
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
⊢ ⋃ y ∈ T₁, f ⁻¹' {y} ⊆ f ⁻¹' t ∩ u

Tactic:
]

Goal state after:
case a
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
⊢ ⋃ y ∈ T₁, f ⁻¹' {y} ⊆ f ⁻¹' t ∩ u
Module: Mathlib.Topology.Compactness.Lindelof

Goal state before:
pp: X : Type u
inst✝ : TopologicalSpace X
s : Set X
hs : ∃ K, (∀ (n : ℕ), IsCompact (K n)) ∧ ⋃ n, K n = s
⊢ IsLindelof s

Tactic:
]

Goal state after:
X : Type u
inst✝ : TopologicalSpace X
s : Set X
hs : ∃ K, (∀ (n : ℕ), IsCompact (K n)) ∧ ⋃ n, K n = s
⊢ IsLindelof s
Module: Mathlib.Topology.Compactness.Lindelof

Goal state before:
pp: X : Type u
inst✝ : TopologicalSpace X
s : Set X
K : ℕ → Set X
hc : ∀ (n : ℕ), IsCompact (K n)
huniv : ⋃ n, K n = s
⊢ IsLindelof (⋃ n, K n)

Tactic:
]

Goal state after:
X : Type u
inst✝ : TopologicalSpace X
s : Set X
K : ℕ → Set X
hc : ∀ (n : ℕ), IsCompact (K n)
huniv : ⋃ n, K n = s
⊢ IsLindelof (⋃ n, K n)
Module: Mathlib.Topology.Connected.Clopen

Goal state before:
pp: case a
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
t' : β
ht' : t' ∈ T₁
⊢ t' ∈ t

Tactic:
]

Goal state after:
case a
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
t' : β
ht' : t' ∈ T₁
⊢ t' ∈ t
Module: Mathlib.Topology.Compactness.Lindelof

Goal state before:
pp: X : Type u
Y : Type v
ι : Type u_1
inst✝² : TopologicalSpace X
inst✝¹ : TopologicalSpace Y
s✝ t : Set X
inst✝ : NonLindelofSpace X
s : Set X
hs : s = univ
⊢ ¬IsLindelof s

Tactic:
]

Goal state after:
X : Type u
Y : Type v
ι : Type u_1
inst✝² : TopologicalSpace X
inst✝¹ : TopologicalSpace Y
s✝ t : Set X
inst✝ : NonLindelofSpace X
s : Set X
hs : s = univ
⊢ ¬IsLindelof s
Module: Mathlib.Topology.Compactness.Lindelof

Goal state before:
pp: X : Type u
Y : Type v
ι : Type u_1
inst✝² : TopologicalSpace X
inst✝¹ : TopologicalSpace Y
s✝ t : Set X
inst✝ : NonLindelofSpace X
s : Set X
hs : s = univ
⊢ ¬IsLindelof univ

Tactic:
]

Goal state after:
X : Type u
Y : Type v
ι : Type u_1
inst✝² : TopologicalSpace X
inst✝¹ : TopologicalSpace Y
s✝ t : Set X
inst✝ : NonLindelofSpace X
s : Set X
hs : s = univ
⊢ ¬IsLindelof univ
Module: Mathlib.Topology.DenseEmbedding

Goal state before:
pp: α : Type u_1
β : Type u_2
γ : Type u_3
inst✝³ : TopologicalSpace α
inst✝² : TopologicalSpace β
i : α → β
inst✝¹ : TopologicalSpace γ
inst✝ : T3Space γ
b : β
f : α → γ
di : IsDenseInducing i
hf : ∀ᶠ (x : β) in 𝓝 b, ∃ c, Tendsto f (comap i (𝓝 x)) (𝓝 c)
φ : β → γ := di.extend f
this : ∀ (b : β), (comap i (𝓝 b)).NeBot
V' : Set γ
V'_in : V' ∈ 𝓝 (φ b)
V'_closed : IsClosed[inst✝¹] V'
V₁ : Set β := {x | Tendsto f (comap i (𝓝 x)) (𝓝 (φ x))}
x : β
c : γ
hc : Tendsto f (comap i (𝓝 x)) (𝓝 (di.extend f x))
⊢ x ∈ V₁

Tactic:
]

Goal state after:
α : Type u_1
β : Type u_2
γ : Type u_3
inst✝³ : TopologicalSpace α
inst✝² : TopologicalSpace β
i : α → β
inst✝¹ : TopologicalSpace γ
inst✝ : T3Space γ
b : β
f : α → γ
di : IsDenseInducing i
hf : ∀ᶠ (x : β) in 𝓝 b, ∃ c, Tendsto f (comap i (𝓝 x)) (𝓝 c)
φ : β → γ := di.extend f
this : ∀ (b : β), (comap i (𝓝 b)).NeBot
V' : Set γ
V'_in : V' ∈ 𝓝 (φ b)
V'_closed : IsClosed[inst✝¹] V'
V₁ : Set β := {x | Tendsto f (comap i (𝓝 x)) (𝓝 (φ x))}
x : β
c : γ
hc : Tendsto f (comap i (𝓝 x)) (𝓝 (di.extend f x))
⊢ x ∈ V₁
Module: Mathlib.Topology.Compactness.Lindelof

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
⊢ ∀ (i' : Set X), IsLindelof i' → ∃ i, IsLindelof i ∧ f ⁻¹' iᶜ ⊆ i'ᶜ

Tactic:
]

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
⊢ ∀ (i' : Set X), IsLindelof i' → ∃ i, IsLindelof i ∧ f ⁻¹' iᶜ ⊆ i'ᶜ
Module: Mathlib.Topology.Compactness.Lindelof

Goal state before:
pp: X : Type u
Y : Type v
inst✝² : TopologicalSpace X
inst✝¹ : TopologicalSpace Y
inst✝ : LindelofSpace X
f : X → Y
hf : Continuous[inst✝², inst✝¹] f
⊢ IsLindelof (f '' univ)

Tactic:
]

Goal state after:
X : Type u
Y : Type v
inst✝² : TopologicalSpace X
inst✝¹ : TopologicalSpace Y
inst✝ : LindelofSpace X
f : X → Y
hf : Continuous[inst✝², inst✝¹] f
⊢ IsLindelof (f '' univ)
Module: Mathlib.Topology.Separation.Regular

Goal state before:
pp: case refine_3
X : Type u_1
inst✝ : TopologicalSpace X
s t : Set X
hSt : Disjoint (closure[inst✝] s) t
hsT : Disjoint s (closure[inst✝] t)
e : Set X := (closure[inst✝] s ∩ closure[inst✝] t)ᶜ
h : NormalSpace ↑e
he : IsOpen[inst✝] e
hst : Disjoint (Subtype.val ⁻¹' closure[inst✝] s) (Subtype.val ⁻¹' closure[inst✝] t)
U : Set X
hU : IsOpen[inst✝] U
hsU : closure[inst✝] s ∩ e ⊆ U ∩ e
V : Set X
hV : IsOpen[inst✝] V
htV : closure[inst✝] t ∩ e ⊆ V ∩ e
hUV : ∀ ⦃a : { x // x ∈ e }⦄, a ∈ Subtype.val ⁻¹' U → a ∉ Subtype.val ⁻¹' V
⊢ ∀ ⦃a : X⦄, a ∈ U ∩ e → a ∉ V ∩ e

Tactic:
]

Goal state after:
case refine_3
X : Type u_1
inst✝ : TopologicalSpace X
s t : Set X
hSt : Disjoint (closure[inst✝] s) t
hsT : Disjoint s (closure[inst✝] t)
e : Set X := (closure[inst✝] s ∩ closure[inst✝] t)ᶜ
h : NormalSpace ↑e
he : IsOpen[inst✝] e
hst : Disjoint (Subtype.val ⁻¹' closure[inst✝] s) (Subtype.val ⁻¹' closure[inst✝] t)
U : Set X
hU : IsOpen[inst✝] U
hsU : closure[inst✝] s ∩ e ⊆ U ∩ e
V : Set X
hV : IsOpen[inst✝] V
htV : closure[inst✝] t ∩ e ⊆ V ∩ e
hUV : ∀ ⦃a : { x // x ∈ e }⦄, a ∈ Subtype.val ⁻¹' U → a ∉ Subtype.val ⁻¹' V
⊢ ∀ ⦃a : X⦄, a ∈ U ∩ e → a ∉ V ∩ e