mathlib-initiative/mathlib-tactics huggingface dataset:
Module: Mathlib.Topology.Separation.Profinite

Goal state before:
pp: X : Type u_4
I✝ : Type u_5
inst✝⁵ : TopologicalSpace X
inst✝⁴ : CompactSpace X
inst✝³ : T2Space X
inst✝² : TotallyDisconnectedSpace X
inst✝¹ : Finite I✝
I : Type u_5
inst✝ : Fintype I
IH :
  ∀ {Z D : I → Set X},
    (∀ (i : I), IsClosed[inst✝⁵] (Z i)) →
      (∀ (i : I), IsClopen (D i)) →
        (∀ (i : I), Z i ⊆ D i) →
          univ.PairwiseDisjoint Z →
            ∃ C,
              (∀ (i : I), IsClopen (C i)) ∧
                (∀ (i : I), Z i ⊆ C i) ∧ (∀ (i : I), C i ⊆ D i) ∧ ⋃ i, D i ⊆ ⋃ i, C i ∧ univ.PairwiseDisjoint C
Z D : Option I → Set X
Z_closed : ∀ (i : Option I), IsClosed[inst✝⁵] (Z i)
D_clopen : ∀ (i : Option I), IsClopen (D i)
Z_subset_D : ∀ (i : Option I), Z i ⊆ D i
Z_disj : univ.PairwiseDisjoint Z
Z' : I → Set X := fun i ↦ Z (some i)
Z'_closed : ∀ (i : I), IsClosed[inst✝⁵] (Z (some i))
Z'_disj : univ.PairwiseDisjoint (Z ∘ some)
U : Set X := D none \ ⋃ i, Z (some i)
U_open : IsOpen[inst✝⁵] U
Z0_subset_U : Z none ⊆ U
V : Set X
V_clopen : IsClopen V
Z0_subset_V : Z none ⊆ V
V_subset_U : V ⊆ U
V_subset_D0 : V ⊆ D none
D' : I → Set X := fun i ↦ D (some i) \ V
D'_clopen : ∀ (i : I), IsClopen (D' i)
Z'_subset_D' : ∀ (i : I), Z' i ⊆ D' i
C' : I → Set X
C'_clopen : ∀ (i : I), IsClopen (C' i)
Z'_subset_C' : ∀ (i : I), Z (some i) ⊆ C' i
C'_subset_D' : ∀ (i : I), C' i ⊆ D' i
C'_cover_D' : ⋃ i, D' i ⊆ ⋃ i, C' i
C'_disj : univ.PairwiseDisjoint C'
C0 : Set X := D none \ ⋃ i, C' i
this : IsClopen C0
⊢ Disjoint V (⋃ i, C' i)

Tactic:
by

Goal state after:
Module: Mathlib.Computability.TuringMachine.Config

Goal state before:
pp: c : Code
⊢ c.Ok

Tactic:
by

Goal state after:
Module: Mathlib.Computability.TuringMachine.Config

Goal state before:
pp: case halt
v : List ℕ
⊢ eval step (stepRet Cont.halt v) = Cfg.halt <$> Cont.halt.eval v

Tactic:
| halt =>

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

Goal state before:
pp: X : Type u_4
I✝ : Type u_5
inst✝⁵ : TopologicalSpace X
inst✝⁴ : CompactSpace X
inst✝³ : T2Space X
inst✝² : TotallyDisconnectedSpace X
inst✝¹ : Finite I✝
I : Type u_5
inst✝ : Fintype I
IH :
  ∀ {Z D : I → Set X},
    (∀ (i : I), IsClosed[inst✝⁵] (Z i)) →
      (∀ (i : I), IsClopen (D i)) →
        (∀ (i : I), Z i ⊆ D i) →
          univ.PairwiseDisjoint Z →
            ∃ C,
              (∀ (i : I), IsClopen (C i)) ∧
                (∀ (i : I), Z i ⊆ C i) ∧ (∀ (i : I), C i ⊆ D i) ∧ ⋃ i, D i ⊆ ⋃ i, C i ∧ univ.PairwiseDisjoint C
Z D : Option I → Set X
Z_closed : ∀ (i : Option I), IsClosed[inst✝⁵] (Z i)
D_clopen : ∀ (i : Option I), IsClopen (D i)
Z_subset_D : ∀ (i : Option I), Z i ⊆ D i
Z_disj : univ.PairwiseDisjoint Z
Z' : I → Set X := fun i ↦ Z (some i)
Z'_closed : ∀ (i : I), IsClosed[inst✝⁵] (Z (some i))
Z'_disj : univ.PairwiseDisjoint (Z ∘ some)
U : Set X := D none \ ⋃ i, Z (some i)
U_open : IsOpen[inst✝⁵] U
Z0_subset_U : Z none ⊆ U
V : Set X
V_clopen : IsClopen V
Z0_subset_V : Z none ⊆ V
V_subset_U : V ⊆ U
V_subset_D0 : V ⊆ D none
D' : I → Set X := fun i ↦ D (some i) \ V
D'_clopen : ∀ (i : I), IsClopen (D' i)
Z'_subset_D' : ∀ (i : I), Z' i ⊆ D' i
C' : I → Set X
C'_clopen : ∀ (i : I), IsClopen (C' i)
Z'_subset_C' : ∀ (i : I), Z (some i) ⊆ C' i
C'_subset_D' : ∀ (i : I), C' i ⊆ D' i
C'_cover_D' : ⋃ i, D' i ⊆ ⋃ i, C' i
C'_disj : univ.PairwiseDisjoint C'
C0 : Set X := D none \ ⋃ i, C' i
this : IsClopen C0
⊢ Z none ⊆ C0

Tactic:
by

Goal state after:
Module: Mathlib.Computability.TuringMachine.Config

Goal state before:
pp: case fix
f : Code
k : Cont
IH : ∀ {v : List ℕ}, eval step (stepRet k v) = Cfg.halt <$> k.eval v
v : List ℕ
⊢ eval step (if v.headI = 0 then stepRet k v.tail else stepNormal f (Cont.fix f k) v.tail) =
    Cfg.halt <$> (fun v ↦ if v.headI = 0 then k.eval v.tail else f.fix.eval v.tail >>= k.eval) v

Tactic:
simp only

Goal state after:
case fix
f : Code
k : Cont
IH : ∀ {v : List ℕ}, eval step (stepRet k v) = Cfg.halt <$> k.eval v
v : List ℕ
⊢ eval step (if v.headI = 0 then stepRet k v.tail else stepNormal f (Cont.fix f k) v.tail) =
    Cfg.halt <$> if v.headI = 0 then k.eval v.tail else f.fix.eval v.tail >>= k.eval
Module: Mathlib.Computability.TuringMachine.StackTuringMachine

Goal state before:
pp: K : Type u_1
Γ : K → Type u_2
Λ : Type u_3
σ : Type u_4
inst✝¹ : DecidableEq K
M : Λ → TM2.Stmt Γ Λ σ
inst✝ : Inhabited Λ
S : Finset Λ
ss : TM2.Supports M S
l' : Λ' K Γ Λ σ
h : l' ∈ trSupp M S
⊢ TM1.SupportsStmt (trSupp M S) (tr M l')

Tactic:
by

Goal state after:
Module: Mathlib.Topology.Category.Profinite.Basic

Goal state before:
pp: X : CompHaus
Y : Profinite
f : X.toProfiniteObj ⟶ Y
y : ↑X.toProfiniteObj.toTop
⊢ (ConcreteCategory.hom
        ((fun g ↦ ConcreteCategory.ofHom { toFun := ⋯.connectedComponentsLift, continuous_toFun := ⋯ })
            ((fun f ↦
                ofHom (fun x ↦ True) ((TopCat.Hom.hom f.hom).comp { toFun := Quotient.mk'', continuous_toFun := ⋯ }))
              f)).hom)
      y =
    (ConcreteCategory.hom f.hom) y

Tactic:
by

Goal state after:
Module: Mathlib.Topology.Category.Profinite.Basic

Goal state before:
pp: X✝ Y✝ : FintypeCat
f : X✝ ⟶ Y✝
⊢ Continuous ⇑(ConcreteCategory.hom f)

Tactic:
by

Goal state after:
Module: Mathlib.Topology.Category.Profinite.Basic

Goal state before:
pp: J : Type v
inst✝ : SmallCategory J
F : J ⥤ Profinite
⊢ TotallyDisconnectedSpace ↑(CompHaus.limitCone (F ⋙ profiniteToCompHaus)).pt.toTop

Tactic:
by

Goal state after:
Module: Mathlib.Topology.Category.Profinite.Basic

Goal state before:
pp: J : Type v
inst✝ : SmallCategory J
F : J ⥤ Profinite
⊢ ∀ ⦃X Y : J⦄ (f : X ⟶ Y),
    ((Functor.const J).obj
              { toTop := (CompHaus.limitCone (F ⋙ profiniteToCompHaus)).pt.toTop, is_compact := ⋯, is_hausdorff := ⋯,
                prop := ⋯ }).map
          f ≫
        InducedCategory.homMk ((CompHaus.limitCone (F ⋙ profiniteToCompHaus)).π.app Y).hom =
      InducedCategory.homMk ((CompHaus.limitCone (F ⋙ profiniteToCompHaus)).π.app X).hom ≫ F.map f

Tactic:
by

Goal state after:
Module: Mathlib.Computability.TuringMachine.Config

Goal state before:
pp: k : Cont
v : List ℕ
⊢ eval step (stepRet k v) = Cfg.halt <$> k.eval v

Tactic:
by

Goal state after:
Module: Mathlib.Computability.TuringMachine.ToPartrec

Goal state before:
pp: p : Γ' → Bool
k₁ k₂ : K'
q : Λ'
s : Option Γ'
L₁ : List Γ'
o : Option Γ'
L₂ : List Γ'
S : K' → List Γ'
h₁ : k₁ ≠ k₂
e : splitAtPred p (S k₁) = (L₁, o, L₂)
⊢ Reaches₁ (TM2.step tr) { l := some (Λ'.move p k₁ k₂ q), var := s, stk := S }
    { l := some q, var := o, stk := update (update S k₁ L₂) k₂ (L₁.reverseAux (S k₂)) }

Tactic:
by

Goal state after:
Module: Mathlib.Computability.TuringMachine.ToPartrec

Goal state before:
pp: q : Λ'
s : Option Γ'
S : K' → List Γ'
⊢ rev ≠ main

Tactic:
by

Goal state after:
Module: Mathlib.Topology.Category.Profinite.Basic

Goal state before:
pp: J : Type v
inst✝ : SmallCategory J
F : J ⥤ Profinite
S : Limits.Cone F
x✝ : S.pt ⟶ (limitCone F).pt
h : ∀ (j : J), x✝ ≫ (limitCone F).π.app j = S.π.app j
j : J
⊢ profiniteToCompHaus.map x✝ ≫ (CompHaus.limitCone (F ⋙ profiniteToCompHaus)).π.app j =
    (profiniteToCompHaus.mapCone S).π.app j

Tactic:
by

Goal state after:
Module: Mathlib.Topology.Category.Profinite.Basic

Goal state before:
pp: ⊢ Limits.PreservesLimits (forget Profinite)

Tactic:
by

Goal state after:
Module: Mathlib.Topology.ExtremallyDisconnected

Goal state before:
pp: X : Type u_1
Y : Type u_2
inst✝² : TopologicalSpace X
inst✝¹ : TopologicalSpace Y
inst✝ : ExtremallyDisconnected X
e : X ≃ₜ Y
U : Set Y
hU : IsOpen U
⊢ IsOpen (closure U)

Tactic:
by

Goal state after:
Module: Mathlib.Topology.ExtremallyDisconnected

Goal state before:
pp: X : Type u
inst✝² : TopologicalSpace X
inst✝¹ : ExtremallyDisconnected X
inst✝ : T2Space X
x : X
a✝¹ : x ∈ univ
y : X
a✝ : y ∈ univ
hxy : x ≠ y
U V : Set X
hUV : IsOpen U ∧ IsOpen V ∧ x ∈ U ∧ y ∈ V ∧ Disjoint U V
⊢ IsOpen (closure U)ᶜ

Tactic:
by

Goal state after:
Module: Mathlib.Topology.ExtremallyDisconnected

Goal state before:
pp: X : Type u
inst✝² : TopologicalSpace X
inst✝¹ : ExtremallyDisconnected X
inst✝ : T2Space X
x : X
a✝¹ : x ∈ univ
y : X
a✝ : y ∈ univ
hxy : x ≠ y
U V : Set X
hUV : IsOpen U ∧ IsOpen V ∧ x ∈ U ∧ y ∈ V ∧ Disjoint U V
⊢ univ ⊆ closure U ∪ (closure U)ᶜ

Tactic:
by

Goal state after:
Module: Mathlib.Topology.ExtremallyDisconnected

Goal state before:
pp: X : Type u
inst✝² : TopologicalSpace X
inst✝¹ : ExtremallyDisconnected X
inst✝ : T2Space X
⊢ IsTotallySeparated univ

Tactic:
by

Goal state after:
Module: Mathlib.Topology.Category.Profinite.Basic

Goal state before:
pp: X Y : Profinite
f : X ⟶ Y
y : ↑Y.toTop
hy : ∀ (a : ↑X.toTop), (ConcreteCategory.hom f) a ≠ y
hf : Epi f
C : Set ((fun X ↦ ↑X.toTop) Y) := Set.range ⇑(ConcreteCategory.hom f)
hC : IsClosed C
U : Set ((fun X ↦ ↑X.toTop) Y) := Cᶜ
⊢ y ∈ U

Tactic:
by

Goal state after:
Module: Mathlib.Computability.TuringMachine.ToPartrec

Goal state before:
pp: case none
p : Γ' → Bool
k₁ k₂ : K'
q : Λ'
s : Option Γ'
L₁ L₂ : List Γ'
S : K' → List Γ'
h₁ : k₁ ≠ rev ∧ k₂ ≠ rev ∧ k₁ ≠ k₂
h₂ : S rev = []
e : splitAtPred p (S k₁) = (L₁, none, L₂)
⊢ TransGen
    (fun a b ↦
      (match a with
        | { l := none, var := var, stk := stk } => none
        | { l := some l, var := v, stk := S } => some (TM2.stepAux (tr l) v S)) =
        some b)
    (TM2.stepAux (tr (Λ'.push k₁ id (Λ'.move (fun x ↦ false) rev k₂ q))) none
      (update (update S k₁ L₂) rev (L₁.reverseAux (S rev))))
    { l := some q, var := none,
      stk :=
        update
          (update S k₁
            ((match (motive := Option Γ' → (List Γ' → List Γ') → (Γ' → List Γ' → List Γ') → List Γ' → List Γ') none, id,
                List.cons with
              | some x, x_1, f => f x
              | none, y, x => y)
              L₂))
          k₂ (L₁ ++ S k₂) }

Tactic:
simp only

Goal state after:
case none
p : Γ' → Bool
k₁ k₂ : K'
q : Λ'
s : Option Γ'
L₁ L₂ : List Γ'
S : K' → List Γ'
h₁ : k₁ ≠ rev ∧ k₂ ≠ rev ∧ k₁ ≠ k₂
h₂ : S rev = []
e : splitAtPred p (S k₁) = (L₁, none, L₂)
⊢ TransGen
    (fun a b ↦
      (match a with
        | { l := none, var := var, stk := stk } => none
        | { l := some l, var := v, stk := S } => some (TM2.stepAux (tr l) v S)) =
        some b)
    (TM2.stepAux (tr (Λ'.push k₁ id (Λ'.move (fun x ↦ false) rev k₂ q))) none
      (update (update S k₁ L₂) rev (L₁.reverseAux (S rev))))
    { l := some q, var := none, stk := update (update S k₁ (id L₂)) k₂ (L₁ ++ S k₂) }
Module: Mathlib.Computability.TuringMachine.ToPartrec

Goal state before:
pp: case some
p : Γ' → Bool
k₁ k₂ : K'
q : Λ'
s : Option Γ'
L₁ L₂ : List Γ'
S : K' → List Γ'
h₁ : k₁ ≠ rev ∧ k₂ ≠ rev ∧ k₁ ≠ k₂
h₂ : S rev = []
val✝ : Γ'
e : splitAtPred p (S k₁) = (L₁, some val✝, L₂)
⊢ TransGen
    (fun a b ↦
      (match a with
        | { l := none, var := var, stk := stk } => none
        | { l := some l, var := v, stk := S } => some (TM2.stepAux (tr l) v S)) =
        some b)
    (TM2.stepAux (tr (Λ'.push k₁ id (Λ'.move (fun x ↦ false) rev k₂ q))) (some val✝)
      (update (update S k₁ L₂) rev (L₁.reverseAux (S rev))))
    { l := some q, var := none,
      stk :=
        update
          (update S k₁
            ((match (motive := Option Γ' → (List Γ' → List Γ') → (Γ' → List Γ' → List Γ') → List Γ' → List Γ')
                some val✝, id, List.cons with
              | some x, x_1, f => f x
              | none, y, x => y)
              L₂))
          k₂ (L₁ ++ S k₂) }

Tactic:
simp only

Goal state after:
case some
p : Γ' → Bool
k₁ k₂ : K'
q : Λ'
s : Option Γ'
L₁ L₂ : List Γ'
S : K' → List Γ'
h₁ : k₁ ≠ rev ∧ k₂ ≠ rev ∧ k₁ ≠ k₂
h₂ : S rev = []
val✝ : Γ'
e : splitAtPred p (S k₁) = (L₁, some val✝, L₂)
⊢ TransGen
    (fun a b ↦
      (match a with
        | { l := none, var := var, stk := stk } => none
        | { l := some l, var := v, stk := S } => some (TM2.stepAux (tr l) v S)) =
        some b)
    (TM2.stepAux (tr (Λ'.push k₁ id (Λ'.move (fun x ↦ false) rev k₂ q))) (some val✝)
      (update (update S k₁ L₂) rev (L₁.reverseAux (S rev))))
    { l := some q, var := none, stk := update (update S k₁ (val✝ :: L₂)) k₂ (L₁ ++ S k₂) }
Module: Mathlib.Topology.ExtremallyDisconnected

Goal state before:
pp: X : Type u
inst✝¹ : TopologicalSpace X
inst✝ : DiscreteTopology X
⊢ CompactT2.Projective (StoneCech X)

Tactic:
by

Goal state after:
Module: Mathlib.Topology.ExtremallyDisconnected

Goal state before:
pp: X : Type u
inst✝² : TopologicalSpace X
inst✝¹ : CompactSpace X
inst✝ : T2Space X
h : Projective X
U : Set X
hU : IsOpen U
Z₁ : Set (X × Bool) := Uᶜ ×ˢ {true}
Z₂ : Set (X × Bool) := closure U ×ˢ {false}
Z : Set (X × Bool) := Z₁ ∪ Z₂
x : X × Bool
hx₁ : x ∈ Z₁
hx₂ : x ∈ Z₂
⊢ False

Tactic:
by

Goal state after:
Module: Mathlib.Topology.Category.Profinite.Basic

Goal state before:
pp: X Y : Profinite
f : X ⟶ Y
y : ↑Y.toTop
hy : ∀ (a : ↑X.toTop), (ConcreteCategory.hom f) a ≠ y
hf : Epi f
C : Set ((fun X ↦ ↑X.toTop) Y) := Set.range ⇑(ConcreteCategory.hom f)
hC : IsClosed C
U : Set ((fun X ↦ ↑X.toTop) Y) := Cᶜ
hyU : y ∈ U
hUy : U ∈ 𝓝 y
V : Set ↑Y.toTop
hV : V ∈ {s | IsClopen s}
hyV : y ∈ V
hVU : V ⊆ U
Z : Profinite := of (ULift.{u, 0} (Fin 2))
g : Y ⟶ Z :=
  ofHom (fun X ↦ TotallyDisconnectedSpace ↑X)
    { toFun := ⇑(LocallyConstant.map ULift.up (LocallyConstant.ofIsClopen hV)), continuous_toFun := ⋯ }
h : Y ⟶ Z := ofHom (fun X ↦ TotallyDisconnectedSpace ↑X) { toFun := fun x ↦ { down := 1 }, continuous_toFun := ⋯ }
⊢ h = g

Tactic:
by

Goal state after:
Module: Mathlib.Topology.ExtremallyDisconnected

Goal state before:
pp: X : Type u
inst✝² : TopologicalSpace X
inst✝¹ : CompactSpace X
inst✝ : T2Space X
h : Projective X
U : Set X
hU : IsOpen U
Z₁ : Set (X × Bool) := Uᶜ ×ˢ {true}
Z₂ : Set (X × Bool) := closure U ×ˢ {false}
Z : Set (X × Bool) := Z₁ ∪ Z₂
hZ₁₂ : Disjoint Z₁ Z₂
hZ₁ : IsClosed Z₁
hZ₂ : IsClosed Z₂
hZ : IsClosed Z
f : ↑Z → X := Prod.fst ∘ Subtype.val
f_cont : Continuous f
⊢ Surjective f

Tactic:
by

Goal state after:
Module: Mathlib.Computability.TuringMachine.ToPartrec

Goal state before:
pp: p : Γ' → Bool
k₁ k₂ : K'
q : Λ'
s : Option Γ'
L₁ : List Γ'
o : Option Γ'
L₂ : List Γ'
S : K' → List Γ'
h₁ : k₁ ≠ rev ∧ k₂ ≠ rev ∧ k₁ ≠ k₂
h₂ : S rev = []
e : splitAtPred p (S k₁) = (L₁, o, L₂)
⊢ Reaches₁ (TM2.step tr) { l := some (move₂ p k₁ k₂ q), var := s, stk := S }
    { l := some q, var := none, stk := update (update S k₁ (o.elim id List.cons L₂)) k₂ (L₁ ++ S k₂) }

Tactic:
by

Goal state after:
Module: Mathlib.Topology.Category.Profinite.Basic

Goal state before:
pp: X Y : Profinite
f : X ⟶ Y
⊢ Epi f ↔ Function.Surjective ⇑(ConcreteCategory.hom f)

Tactic:
by

Goal state after:
Module: Mathlib.Topology.Category.CompHaus.Projective

Goal state before:
pp: X : Type u_1
Y Z : CompHaus
f : of (Ultrafilter X) ⟶ Z
g : Y ⟶ Z
hg : Epi g
⊢ ∃ f', f' ≫ g = f

Tactic:
by

Goal state after:
Module: Mathlib.Topology.ExtremallyDisconnected

Goal state before:
pp: X : Type u
inst✝² : TopologicalSpace X
inst✝¹ : CompactSpace X
inst✝ : T2Space X
h : Projective X
U : Set X
hU : IsOpen U
Z₁ : Set (X × Bool) := Uᶜ ×ˢ {true}
Z₂ : Set (X × Bool) := closure U ×ˢ {false}
Z : Set (X × Bool) := Z₁ ∪ Z₂
hZ₁₂ : Disjoint Z₁ Z₂
hZ₁ : IsClosed Z₁
hZ₂ : IsClosed Z₂
hZ : IsClosed Z
f : ↑Z → X := Prod.fst ∘ Subtype.val
f_cont : Continuous f
f_sur : Surjective f
this✝ : CompactSpace ↑Z
g : X → ↑Z
hg : Continuous g
g_sec : f ∘ g = id
φ : X → X × Bool := Subtype.val ∘ g
hφ : Continuous φ
hφ₁ : ∀ (x : X), (φ x).1 = x
this : closure U = φ ⁻¹' Z₂
⊢ IsOpen (closure U)

Tactic:
by

Goal state after:
Module: Mathlib.Topology.ExtremallyDisconnected

Goal state before:
pp: X : Type u
inst✝² : TopologicalSpace X
inst✝¹ : CompactSpace X
inst✝ : T2Space X
h : Projective X
⊢ ExtremallyDisconnected X

Tactic:
by

Goal state after:
Module: Mathlib.Topology.ExtremallyDisconnected

Goal state before:
pp: A D : Type u
inst✝³ : TopologicalSpace A
inst✝² : TopologicalSpace D
inst✝¹ : T1Space A
inst✝ : CompactSpace D
X : D → A
X_cont : Continuous X
X_surj : Surjective X
S : Set (Set D) := {E | IsClosed E ∧ X '' E = univ}
this : ∀ C ⊆ S, IsChain (fun x1 x2 ↦ x1 ⊆ x2) C → ∃ s ∈ S, ∀ c ∈ C, s ⊆ c
⊢ ∃ E, CompactSpace ↑E ∧ X '' E = univ ∧ ∀ (E₀ : Set ↑E), E₀ ≠ univ → IsClosed E₀ → E.domRestrict X '' E₀ ≠ univ

Tactic:
by

Goal state after:
Module: Mathlib.Topology.ExtremallyDisconnected

Goal state before:
pp: A D : Type u
inst✝³ : TopologicalSpace A
inst✝² : TopologicalSpace D
inst✝¹ : T1Space A
inst✝ : CompactSpace D
X : D → A
X_cont : Continuous X
X_surj : Surjective X
⊢ ∃ E, CompactSpace ↑E ∧ X '' E = univ ∧ ∀ (E₀ : Set ↑E), E₀ ≠ univ → IsClosed E₀ → E.domRestrict X '' E₀ ≠ univ

Tactic:
by

Goal state after:
Module: Mathlib.Topology.ExtremallyDisconnected

Goal state before:
pp: case pos
A E : Type u
inst✝¹ : TopologicalSpace A
inst✝ : TopologicalSpace E
ρ : E → A
ρ_cont : Continuous ρ
ρ_surj : Surjective ρ
zorn_subset : ∀ (E₀ : Set E), E₀ ≠ univ → IsClosed E₀ → ρ '' E₀ ≠ univ
G : Set E
hG : IsOpen G
G_empty : G = ∅
⊢ ρ '' G ⊆ closure (ρ '' Gᶜ)ᶜ

Tactic:
simpa only [G_empty, image_empty] using empty_subset _

Goal state after:
Module: Mathlib.Topology.ExtremallyDisconnected

Goal state before:
pp: A E : Type u
inst✝¹ : TopologicalSpace A
inst✝ : TopologicalSpace E
ρ : E → A
ρ_cont : Continuous ρ
ρ_surj : Surjective ρ
zorn_subset : ∀ (E₀ : Set E), E₀ ≠ univ → IsClosed E₀ → ρ '' E₀ ≠ univ
G : Set E
hG : IsOpen G
G_empty : ¬G = ∅
N : Set A
N_open : IsOpen N
e : E
he : e ∈ G
ha : ρ e ∈ ρ '' G
hN : ρ e ∈ N
nonempty : (G ∩ ρ ⁻¹' N).Nonempty
is_open : IsOpen (G ∩ ρ ⁻¹' N)
ne_univ : ρ '' (G ∩ ρ ⁻¹' N)ᶜ ≠ univ
x : A
hx : x ∈ (ρ '' (G ∩ ρ ⁻¹' N)ᶜ)ᶜ
h : x ∈ ρ '' Gᶜ
⊢ Gᶜ ⊆ (G ∩ ρ ⁻¹' N)ᶜ

Tactic:
by

Goal state after:
Module: Mathlib.Topology.ExtremallyDisconnected

Goal state before:
pp: A E : Type u
inst✝¹ : TopologicalSpace A
inst✝ : TopologicalSpace E
ρ : E → A
ρ_cont : Continuous ρ
ρ_surj : Surjective ρ
zorn_subset : ∀ (E₀ : Set E), E₀ ≠ univ → IsClosed E₀ → ρ '' E₀ ≠ univ
G : Set E
hG : IsOpen G
G_empty : ¬G = ∅
N : Set A
N_open : IsOpen N
e : E
he : e ∈ G
ha : ρ e ∈ ρ '' G
hN : ρ e ∈ N
nonempty : (G ∩ ρ ⁻¹' N).Nonempty
is_open : IsOpen (G ∩ ρ ⁻¹' N)
ne_univ : ρ '' (G ∩ ρ ⁻¹' N)ᶜ ≠ univ
y : E
hx : ρ y ∈ (ρ '' (G ∩ ρ ⁻¹' N)ᶜ)ᶜ
hx' : ρ y ∈ (ρ '' Gᶜ)ᶜ
⊢ y ∈ G ∩ ρ ⁻¹' N

Tactic:
by

Goal state after:
Module: Mathlib.Topology.ExtremallyDisconnected

Goal state before:
pp: A E : Type u
inst✝¹ : TopologicalSpace A
inst✝ : TopologicalSpace E
ρ : E → A
ρ_cont : Continuous ρ
ρ_surj : Surjective ρ
zorn_subset : ∀ (E₀ : Set E), E₀ ≠ univ → IsClosed E₀ → ρ '' E₀ ≠ univ
G : Set E
hG : IsOpen G
⊢ ρ '' G ⊆ closure (ρ '' Gᶜ)ᶜ

Tactic:
by_cases G_empty : G = ∅
  · simpa only [G_empty, image_empty] using empty_subset _
  · -- let $a \in \rho(G)$
    intro a ha
    rw [mem_closure_iff]
    -- let $N$ be a neighbourhood of $a$
    intro N N_open hN
    -- get $x \in A$ from nonempty open $G \cap \rho^{-1}(N)$
    rcases (G.mem_image ρ a).mp ha with ⟨e, he, rfl⟩
    have nonempty : (G ∩ ρ ⁻¹' N).Nonempty := ⟨e, mem_inter he <| mem_preimage.mpr hN⟩
    have is_open : IsOpen <| G ∩ ρ ⁻¹' N := hG.inter <| N_open.preimage ρ_cont
    have ne_univ : ρ '' (G ∩ ρ ⁻¹' N)ᶜ ≠ univ :=
      zorn_subset _ (compl_ne_univ.mpr nonempty) is_open.isClosed_compl
    rcases nonempty_compl.mpr ne_univ with ⟨x, hx⟩
    -- prove $x \in N \cap (A \setminus \rho(E \setminus G))$
    have hx' : x ∈ (ρ '' Gᶜ)ᶜ := fun h => hx <| image_mono (by simp) h
    rcases ρ_surj x with ⟨y, rfl⟩
    have hy : y ∈ G ∩ ρ ⁻¹' N := by simpa using mt (mem_image_of_mem ρ) <| mem_compl hx
    exact ⟨ρ y, mem_inter (mem_preimage.mp <| mem_of_mem_inter_right hy) hx'⟩

Goal state after:
Module: Mathlib.Topology.ExtremallyDisconnected

Goal state before:
pp: A E : Type u
inst✝¹ : TopologicalSpace A
inst✝ : TopologicalSpace E
ρ : E → A
ρ_cont : Continuous ρ
ρ_surj : Surjective ρ
zorn_subset : ∀ (E₀ : Set E), E₀ ≠ univ → IsClosed E₀ → ρ '' E₀ ≠ univ
G : Set E
hG : IsOpen G
⊢ ρ '' G ⊆ closure (ρ '' Gᶜ)ᶜ

Tactic:
by

Goal state after:
Module: Mathlib.Topology.ExtremallyDisconnected

Goal state before:
pp: A E : Type u
inst✝⁵ : TopologicalSpace A
inst✝⁴ : TopologicalSpace E
inst✝³ : ExtremallyDisconnected A
inst✝² : T2Space A
inst✝¹ : T2Space E
inst✝ : CompactSpace E
ρ : E → A
ρ_cont : Continuous ρ
ρ_surj : Surjective ρ
zorn_subset : ∀ (E₀ : Set E), E₀ ≠ univ → IsClosed E₀ → ρ '' E₀ ≠ univ
x₁ x₂ : E
hρx : ρ x₁ = ρ x₂
hx : ¬x₁ = x₂
G₁ G₂ : Set E
G₁_open : IsOpen G₁
G₂_open : IsOpen G₂
hx₁ : x₁ ∈ G₁
hx₂ : x₂ ∈ G₂
disj : Disjoint G₁ G₂
G₁_comp : IsCompact G₁ᶜ
G₂_comp : IsCompact G₂ᶜ
G₁_open' : IsOpen (ρ '' G₁ᶜ)ᶜ
G₂_open' : IsOpen (ρ '' G₂ᶜ)ᶜ
⊢ Disjoint (ρ '' G₁ᶜ)ᶜ (ρ '' G₂ᶜ)ᶜ

Tactic:
by

Goal state after:
Module: Mathlib.Computability.TuringMachine.ToPartrec

Goal state before:
pp: case cons.nil
p : Γ' → Bool
k : K'
q : Λ'
o : Option Γ'
L₂ : List Γ'
a : Γ'
L₁ : List Γ'
IH :
  ∀ {s : Option Γ'} {S : K' → List Γ'},
    splitAtPred p (S k) = (L₁, o, L₂) →
      Reaches₁ (TM2.step tr) { l := some (Λ'.clear p k q), var := s, stk := S }
        { l := some q, var := o, stk := update S k L₂ }
s : Option Γ'
S : K' → List Γ'
e : splitAtPred p (S k) = (a :: L₁, o, L₂)
e₁ : S k = []
⊢ TransGen
    (fun a b ↦
      (match a with
        | { l := none, var := var, stk := stk } => none
        | { l := some l, var := v, stk := S } => some (TM2.stepAux (tr l) v S)) =
        some b)
    (bif
        match [].head?, true, p with
        | some x, x_1, f => f x
        | none, y, x => y then
      { l := some q, var := [].head?, stk := update S k [].tail }
    else { l := some (Λ'.clear p k q), var := [].head?, stk := update S k [].tail })
    { l := some q, var := o, stk := update S k L₂ }

Tactic:
rw [e₁, splitAtPred] at e

Goal state after:
case cons.nil
p : Γ' → Bool
k : K'
q : Λ'
o : Option Γ'
L₂ : List Γ'
a : Γ'
L₁ : List Γ'
IH :
  ∀ {s : Option Γ'} {S : K' → List Γ'},
    splitAtPred p (S k) = (L₁, o, L₂) →
      Reaches₁ (TM2.step tr) { l := some (Λ'.clear p k q), var := s, stk := S }
        { l := some q, var := o, stk := update S k L₂ }
s : Option Γ'
S : K' → List Γ'
e : ([], none, []) = (a :: L₁, o, L₂)
e₁ : S k = []
⊢ TransGen
    (fun a b ↦
      (match a with
        | { l := none, var := var, stk := stk } => none
        | { l := some l, var := v, stk := S } => some (TM2.stepAux (tr l) v S)) =
        some b)
    (bif
        match [].head?, true, p with
        | some x, x_1, f => f x
        | none, y, x => y then
      { l := some q, var := [].head?, stk := update S k [].tail }
    else { l := some (Λ'.clear p k q), var := [].head?, stk := update S k [].tail })
    { l := some q, var := o, stk := update S k L₂ }
Module: Mathlib.Topology.ExtremallyDisconnected

Goal state before:
pp: A E : Type u
inst✝⁵ : TopologicalSpace A
inst✝⁴ : TopologicalSpace E
inst✝³ : ExtremallyDisconnected A
inst✝² : T2Space A
inst✝¹ : T2Space E
inst✝ : CompactSpace E
ρ : E → A
ρ_cont : Continuous ρ
ρ_surj : Surjective ρ
zorn_subset : ∀ (E₀ : Set E), E₀ ≠ univ → IsClosed E₀ → ρ '' E₀ ≠ univ
⊢ Injective ρ

Tactic:
by

Goal state after: