mathlib-initiative/mathlib-tactics huggingface dataset:
Module: Mathlib.CategoryTheory.Limits.VanKampen

Goal state before:
pp: J : Type v'
inst✝² : Category.{u', v'} J
C : Type u
inst✝¹ : Category.{v, u} C
F G : J ⥤ C
α : F ⟶ G
inst✝ : IsIso α
c : Cocone G
hc : IsVanKampenColimit c
F' : J ⥤ C
c' : Cocone F'
⊢ ∀ (α_1 : F' ⟶ F) (f : c'.pt ⟶ ((Cocone.precompose α).obj c).pt),
    α_1 ≫ ((Cocone.precompose α).obj c).ι = c'.ι ≫ (const J).map f →
      NatTrans.Equifibered α_1 →
        (Nonempty (IsColimit c') ↔
          ∀ (j : J), IsPullback (c'.ι.app j) (α_1.app j) f (((Cocone.precompose α).obj c).ι.app j))

Tactic:
α'

Goal state after:
J : Type v'
inst✝² : Category.{u', v'} J
C : Type u
inst✝¹ : Category.{v, u} C
F G : J ⥤ C
α : F ⟶ G
inst✝ : IsIso α
c : Cocone G
hc : IsVanKampenColimit c
F' : J ⥤ C
c' : Cocone F'
α' : F' ⟶ F
⊢ ∀ (f : c'.pt ⟶ ((Cocone.precompose α).obj c).pt),
    α' ≫ ((Cocone.precompose α).obj c).ι = c'.ι ≫ (const J).map f →
      NatTrans.Equifibered α' →
        (Nonempty (IsColimit c') ↔
          ∀ (j : J), IsPullback (c'.ι.app j) (α'.app j) f (((Cocone.precompose α).obj c).ι.app j))
Module: Mathlib.CategoryTheory.Limits.VanKampen

Goal state before:
pp: J : Type v'
inst✝² : Category.{u', v'} J
C : Type u
inst✝¹ : Category.{v, u} C
F G : J ⥤ C
α : F ⟶ G
inst✝ : IsIso α
c : Cocone G
hc : IsUniversalColimit c
F' : J ⥤ C
c' : Cocone F'
⊢ ∀ (α_1 : F' ⟶ F) (f : c'.pt ⟶ ((Cocone.precompose α).obj c).pt),
    α_1 ≫ ((Cocone.precompose α).obj c).ι = c'.ι ≫ (const J).map f →
      NatTrans.Equifibered α_1 →
        (∀ (j : J), IsPullback (c'.ι.app j) (α_1.app j) f (((Cocone.precompose α).obj c).ι.app j)) →
          Nonempty (IsColimit c')

Tactic:
α'

Goal state after:
J : Type v'
inst✝² : Category.{u', v'} J
C : Type u
inst✝¹ : Category.{v, u} C
F G : J ⥤ C
α : F ⟶ G
inst✝ : IsIso α
c : Cocone G
hc : IsUniversalColimit c
F' : J ⥤ C
c' : Cocone F'
α' : F' ⟶ F
⊢ ∀ (f : c'.pt ⟶ ((Cocone.precompose α).obj c).pt),
    α' ≫ ((Cocone.precompose α).obj c).ι = c'.ι ≫ (const J).map f →
      NatTrans.Equifibered α' →
        (∀ (j : J), IsPullback (c'.ι.app j) (α'.app j) f (((Cocone.precompose α).obj c).ι.app j)) →
          Nonempty (IsColimit c')
Module: Mathlib.CategoryTheory.Limits.VanKampen

Goal state before:
pp: J : Type v'
inst✝² : Category.{u', v'} J
C : Type u
inst✝¹ : Category.{v, u} C
F G : J ⥤ C
α : F ⟶ G
inst✝ : IsIso α
c : Cocone G
hc : IsUniversalColimit c
⊢ IsUniversalColimit ((Cocone.precompose α).obj c)

Tactic:
intro F' c' α' f e hα H

Goal state after:
J : Type v'
inst✝² : Category.{u', v'} J
C : Type u
inst✝¹ : Category.{v, u} C
F G : J ⥤ C
α : F ⟶ G
inst✝ : IsIso α
c : Cocone G
hc : IsUniversalColimit c
F' : J ⥤ C
c' : Cocone F'
α' : F' ⟶ F
f : c'.pt ⟶ ((Cocone.precompose α).obj c).pt
e : α' ≫ ((Cocone.precompose α).obj c).ι = c'.ι ≫ (const J).map f
hα : NatTrans.Equifibered α'
H : ∀ (j : J), IsPullback (c'.ι.app j) (α'.app j) f (((Cocone.precompose α).obj c).ι.app j)
⊢ Nonempty (IsColimit c')
Module: Mathlib.Topology.Category.TopCat.Limits.Products

Goal state before:
pp: case mpr.refine_3
X Y : TopCat
c : BinaryCofan X Y
h₁ : IsOpenEmbedding ⇑(ConcreteCategory.hom c.inl)
h₂ : IsOpenEmbedding ⇑(ConcreteCategory.hom c.inr)
h₃ : IsCompl (range ⇑(ConcreteCategory.hom c.inl)) (range ⇑(ConcreteCategory.hom c.inr))
this :
  ∀ (x : ↑(((Functor.const (Discrete WalkingPair)).obj c.pt).obj { as := WalkingPair.left })),
    x ∈ range ⇑(ConcreteCategory.hom c.inl) ∨ x ∈ range ⇑(ConcreteCategory.hom c.inr)
⊢ ∀ {T : TopCat} (f : X ⟶ T) (g : Y ⟶ T),
    c.inr ≫
        ofHom
          {
            toFun := fun x ↦
              if h : x ∈ range ⇑(ConcreteCategory.hom c.inl) then
                (ConcreteCategory.hom f) ((Equiv.ofInjective ⇑(ConcreteCategory.hom c.inl) ⋯).symm ⟨x, h⟩)
              else (ConcreteCategory.hom g) ((Equiv.ofInjective ⇑(ConcreteCategory.hom c.inr) ⋯).symm ⟨x, ⋯⟩),
            continuous_toFun := ⋯ } =
      g

Tactic:
intro T f g
        ext x
        dsimp
        rw [dif_neg]
        · exact congr_arg g (Equiv.ofInjective_symm_apply _ _)
        · rintro ⟨y, e⟩
          have : c.inr x ∈ Set.range c.inl ⊓ Set.range c.inr := ⟨⟨_, e⟩, ⟨_, rfl⟩⟩
          rwa [disjoint_iff.mp h₃.1] at this

Goal state after:
Module: Mathlib.CategoryTheory.Extensive

Goal state before:
pp: C : Type u
inst✝² : Category.{v, u} C
inst✝¹ : HasFiniteCoproducts C
inst✝ : HasPullbacksOfInclusions C
T : C
HT : IsTerminal T
c₀ : BinaryCofan T T
hc₀ : IsColimit c₀
H :
  ∀ {X' Y' : C} (c' : BinaryCofan X' Y') (αX : X' ⟶ T) (αY : Y' ⟶ T) (f : c'.pt ⟶ c₀.pt),
    αX ≫ c₀.inl = c'.inl ≫ f →
      αY ≫ c₀.inr = c'.inr ≫ f →
        (Nonempty (IsColimit c') ↔ IsPullback c'.inl αX f c₀.inl ∧ IsPullback c'.inr αY f c₀.inr)
X Y : C
c : BinaryCofan X Y
hc : IsColimit c
X' Y' : C
c' : BinaryCofan X' Y'
αX : X' ⟶ X
αY : Y' ⟶ Y
f : c'.pt ⟶ c.pt
hX : αX ≫ c.inl = c'.inl ≫ f
hY : αY ≫ c.inr = c'.inr ≫ f
d : c.pt ⟶ ((Functor.const (Discrete WalkingPair)).obj c₀.pt).obj { as := WalkingPair.left }
hd : c.inl ≫ d = HT.from X ≫ c₀.inl
hd' : c.inr ≫ d = HT.from Y ≫ c₀.inr
⊢ Nonempty (IsColimit c') ↔ IsPullback c'.inl αX f c.inl ∧ IsPullback c'.inr αY f c.inr

Tactic:
rw [H c' (αX ≫ HT.from _) (αY ≫ HT.from _) (f ≫ d) (by rw [← reassoc_of% hX, hd, Category.assoc])
      (by rw [← reassoc_of% hY, hd', Category.assoc])]

Goal state after:
C : Type u
inst✝² : Category.{v, u} C
inst✝¹ : HasFiniteCoproducts C
inst✝ : HasPullbacksOfInclusions C
T : C
HT : IsTerminal T
c₀ : BinaryCofan T T
hc₀ : IsColimit c₀
H :
  ∀ {X' Y' : C} (c' : BinaryCofan X' Y') (αX : X' ⟶ T) (αY : Y' ⟶ T) (f : c'.pt ⟶ c₀.pt),
    αX ≫ c₀.inl = c'.inl ≫ f →
      αY ≫ c₀.inr = c'.inr ≫ f →
        (Nonempty (IsColimit c') ↔ IsPullback c'.inl αX f c₀.inl ∧ IsPullback c'.inr αY f c₀.inr)
X Y : C
c : BinaryCofan X Y
hc : IsColimit c
X' Y' : C
c' : BinaryCofan X' Y'
αX : X' ⟶ X
αY : Y' ⟶ Y
f : c'.pt ⟶ c.pt
hX : αX ≫ c.inl = c'.inl ≫ f
hY : αY ≫ c.inr = c'.inr ≫ f
d : c.pt ⟶ ((Functor.const (Discrete WalkingPair)).obj c₀.pt).obj { as := WalkingPair.left }
hd : c.inl ≫ d = HT.from X ≫ c₀.inl
hd' : c.inr ≫ d = HT.from Y ≫ c₀.inr
⊢ IsPullback c'.inl (αX ≫ HT.from X) (f ≫ d) c₀.inl ∧ IsPullback c'.inr (αY ≫ HT.from Y) (f ≫ d) c₀.inr ↔
    IsPullback c'.inl αX f c.inl ∧ IsPullback c'.inr αY f c.inr
Module: Mathlib.CategoryTheory.Adhesive.Basic

Goal state before:
pp: C : Type u
inst✝² : Category.{v, u} C
W E X Z : C
c : BinaryCofan W E
inst✝¹ : FinitaryExtensive C
inst✝ : HasPullbacks C
hc : IsColimit c
f : W ⟶ X
h : X ⟶ Z
i : c.pt ⟶ Z
H : IsPushout f c.inl h i
hc₁ : IsColimit (BinaryCofan.mk (c.inr ≫ i) h)
W' X' Y' Z' : C
f' : W' ⟶ X'
g' : W' ⟶ Y'
h' : X' ⟶ Z'
i' : Y' ⟶ Z'
αW : W' ⟶ W
αX : X' ⟶ X
αY : Y' ⟶ ((Functor.const (Discrete WalkingPair)).obj c.pt).obj { as := WalkingPair.left }
αZ : Z' ⟶ Z
hf : IsPullback f' αW αX f
hg : IsPullback g' αW αY c.inl
hh : CommSq h' αX αZ h
hi : CommSq i' αY αZ i
w : CommSq f' g' h' i'
hc₂ : IsColimit (BinaryCofan.mk g' (pullback.fst αY c.inr))
⊢ Nonempty (IsColimit (BinaryCofan.mk ((BinaryCofan.mk g' (pullback.fst αY c.inr)).inr ≫ i') h')) ↔
    IsPullback h' αX αZ h ∧ IsPullback i' αY αZ i

Tactic:
refine ((BinaryCofan.isVanKampen_iff _).mp (FinitaryExtensive.vanKampen _ hc₁)
    (BinaryCofan.mk _ _) (pullback.snd _ _) _ _ ?_ hh.w.symm).trans ?_

Goal state after:
case refine_1
C : Type u
inst✝² : Category.{v, u} C
W E X Z : C
c : BinaryCofan W E
inst✝¹ : FinitaryExtensive C
inst✝ : HasPullbacks C
hc : IsColimit c
f : W ⟶ X
h : X ⟶ Z
i : c.pt ⟶ Z
H : IsPushout f c.inl h i
hc₁ : IsColimit (BinaryCofan.mk (c.inr ≫ i) h)
W' X' Y' Z' : C
f' : W' ⟶ X'
g' : W' ⟶ Y'
h' : X' ⟶ Z'
i' : Y' ⟶ Z'
αW : W' ⟶ W
αX : X' ⟶ X
αY : Y' ⟶ ((Functor.const (Discrete WalkingPair)).obj c.pt).obj { as := WalkingPair.left }
αZ : Z' ⟶ Z
hf : IsPullback f' αW αX f
hg : IsPullback g' αW αY c.inl
hh : CommSq h' αX αZ h
hi : CommSq i' αY αZ i
w : CommSq f' g' h' i'
hc₂ : IsColimit (BinaryCofan.mk g' (pullback.fst αY c.inr))
⊢ pullback.snd αY c.inr ≫ (BinaryCofan.mk (c.inr ≫ i) h).inl =
    (BinaryCofan.mk ((BinaryCofan.mk g' (pullback.fst αY c.inr)).inr ≫ i') h').inl ≫ αZ

case refine_2
C : Type u
inst✝² : Category.{v, u} C
W E X Z : C
c : BinaryCofan W E
inst✝¹ : FinitaryExtensive C
inst✝ : HasPullbacks C
hc : IsColimit c
f : W ⟶ X
h : X ⟶ Z
i : c.pt ⟶ Z
H : IsPushout f c.inl h i
hc₁ : IsColimit (BinaryCofan.mk (c.inr ≫ i) h)
W' X' Y' Z' : C
f' : W' ⟶ X'
g' : W' ⟶ Y'
h' : X' ⟶ Z'
i' : Y' ⟶ Z'
αW : W' ⟶ W
αX : X' ⟶ X
αY : Y' ⟶ ((Functor.const (Discrete WalkingPair)).obj c.pt).obj { as := WalkingPair.left }
αZ : Z' ⟶ Z
hf : IsPullback f' αW αX f
hg : IsPullback g' αW αY c.inl
hh : CommSq h' αX αZ h
hi : CommSq i' αY αZ i
w : CommSq f' g' h' i'
hc₂ : IsColimit (BinaryCofan.mk g' (pullback.fst αY c.inr))
⊢ IsPullback (BinaryCofan.mk ((BinaryCofan.mk g' (pullback.fst αY c.inr)).inr ≫ i') h').inl (pullback.snd αY c.inr) αZ
        (BinaryCofan.mk (c.inr ≫ i) h).inl ∧
      IsPullback (BinaryCofan.mk ((BinaryCofan.mk g' (pullback.fst αY c.inr)).inr ≫ i') h').inr αX αZ
        (BinaryCofan.mk (c.inr ≫ i) h).inr ↔
    IsPullback h' αX αZ h ∧ IsPullback i' αY αZ i
Module: Mathlib.CategoryTheory.Adhesive.Basic

Goal state before:
pp: C : Type u
inst✝² : Category.{v, u} C
W E X Z : C
c : BinaryCofan W E
inst✝¹ : FinitaryExtensive C
inst✝ : HasPullbacks C
hc : IsColimit c
f : W ⟶ X
h : X ⟶ Z
i : c.pt ⟶ Z
H : IsPushout f c.inl h i
hc₁ : IsColimit (BinaryCofan.mk (c.inr ≫ i) h)
W' X' Y' Z' : C
f' : W' ⟶ X'
g' : W' ⟶ Y'
h' : X' ⟶ Z'
i' : Y' ⟶ Z'
αW : W' ⟶ W
αX : X' ⟶ X
αY : Y' ⟶ ((Functor.const (Discrete WalkingPair)).obj c.pt).obj { as := WalkingPair.left }
αZ : Z' ⟶ Z
hf : IsPullback f' αW αX f
hg : IsPullback g' αW αY c.inl
hh : CommSq h' αX αZ h
hi : CommSq i' αY αZ i
w : CommSq f' g' h' i'
hc₂ : IsColimit (BinaryCofan.mk g' (pullback.fst αY c.inr))
hc₃ :
  IsPullback (BinaryCofan.mk ((BinaryCofan.mk g' (pullback.fst αY c.inr)).inr ≫ i') h').inl (pullback.snd αY c.inr) αZ
    (BinaryCofan.mk (c.inr ≫ i) h).inl
hc₄ :
  IsPullback (BinaryCofan.mk ((BinaryCofan.mk g' (pullback.fst αY c.inr)).inr ≫ i') h').inr αX αZ
    (BinaryCofan.mk (c.inr ≫ i) h).inr
Y'' : C := pullback αZ i
cmp : Y' ⟶ Y'' := pullback.lift i' αY ⋯
e₁ : (g' ≫ cmp) ≫ pullback.snd αZ i = αW ≫ c.inl
e₂ : (pullback.fst αY c.inr ≫ cmp) ≫ pullback.snd αZ i = pullback.snd αY c.inr ≫ c.inr
⊢ IsPullback (pullback.fst αY c.inr ≫ cmp ≫ pullback.fst αZ i) (pullback.snd αY c.inr) αZ (c.inr ≫ i)

Tactic:
pullback.lift_fst

Goal state after:
C : Type u
inst✝² : Category.{v, u} C
W E X Z : C
c : BinaryCofan W E
inst✝¹ : FinitaryExtensive C
inst✝ : HasPullbacks C
hc : IsColimit c
f : W ⟶ X
h : X ⟶ Z
i : c.pt ⟶ Z
H : IsPushout f c.inl h i
hc₁ : IsColimit (BinaryCofan.mk (c.inr ≫ i) h)
W' X' Y' Z' : C
f' : W' ⟶ X'
g' : W' ⟶ Y'
h' : X' ⟶ Z'
i' : Y' ⟶ Z'
αW : W' ⟶ W
αX : X' ⟶ X
αY : Y' ⟶ ((Functor.const (Discrete WalkingPair)).obj c.pt).obj { as := WalkingPair.left }
αZ : Z' ⟶ Z
hf : IsPullback f' αW αX f
hg : IsPullback g' αW αY c.inl
hh : CommSq h' αX αZ h
hi : CommSq i' αY αZ i
w : CommSq f' g' h' i'
hc₂ : IsColimit (BinaryCofan.mk g' (pullback.fst αY c.inr))
hc₃ :
  IsPullback (BinaryCofan.mk ((BinaryCofan.mk g' (pullback.fst αY c.inr)).inr ≫ i') h').inl (pullback.snd αY c.inr) αZ
    (BinaryCofan.mk (c.inr ≫ i) h).inl
hc₄ :
  IsPullback (BinaryCofan.mk ((BinaryCofan.mk g' (pullback.fst αY c.inr)).inr ≫ i') h').inr αX αZ
    (BinaryCofan.mk (c.inr ≫ i) h).inr
Y'' : C := pullback αZ i
cmp : Y' ⟶ Y'' := pullback.lift i' αY ⋯
e₁ : (g' ≫ cmp) ≫ pullback.snd αZ i = αW ≫ c.inl
e₂ : (pullback.fst αY c.inr ≫ cmp) ≫ pullback.snd αZ i = pullback.snd αY c.inr ≫ c.inr
⊢ IsPullback (pullback.fst αY c.inr ≫ i') (pullback.snd αY c.inr) αZ (c.inr ≫ i)
Module: Mathlib.CategoryTheory.Adhesive.Basic

Goal state before:
pp: C : Type u
inst✝² : Category.{v, u} C
W E X Z : C
c : BinaryCofan W E
inst✝¹ : FinitaryExtensive C
inst✝ : HasPullbacks C
hc : IsColimit c
f : W ⟶ X
h : X ⟶ Z
i : c.pt ⟶ Z
H : IsPushout f c.inl h i
hc₁ : IsColimit (BinaryCofan.mk (c.inr ≫ i) h)
W' X' Y' Z' : C
f' : W' ⟶ X'
g' : W' ⟶ Y'
h' : X' ⟶ Z'
i' : Y' ⟶ Z'
αW : W' ⟶ W
αX : X' ⟶ X
αY : Y' ⟶ ((Functor.const (Discrete WalkingPair)).obj c.pt).obj { as := WalkingPair.left }
αZ : Z' ⟶ Z
hf : IsPullback f' αW αX f
hg : IsPullback g' αW αY c.inl
hh : CommSq h' αX αZ h
hi : CommSq i' αY αZ i
w : CommSq f' g' h' i'
hc₂ : IsColimit (BinaryCofan.mk g' (pullback.fst αY c.inr))
hc₃ :
  IsPullback (BinaryCofan.mk ((BinaryCofan.mk g' (pullback.fst αY c.inr)).inr ≫ i') h').inl (pullback.snd αY c.inr) αZ
    (BinaryCofan.mk (c.inr ≫ i) h).inl
hc₄✝ :
  IsPullback (BinaryCofan.mk ((BinaryCofan.mk g' (pullback.fst αY c.inr)).inr ≫ i') h').inr αX αZ
    (BinaryCofan.mk (c.inr ≫ i) h).inr
Y'' : C := pullback αZ i
cmp : Y' ⟶ Y'' := pullback.lift i' αY ⋯
e₁ : (g' ≫ cmp) ≫ pullback.snd αZ i = αW ≫ c.inl
e₂ : (pullback.fst αY c.inr ≫ cmp) ≫ pullback.snd αZ i = pullback.snd αY c.inr ≫ c.inr
hc₄ : IsColimit (BinaryCofan.mk (g' ≫ cmp) (pullback.fst αY c.inr ≫ cmp))
this : cmp = (hc₂.coconePointUniqueUpToIso hc₄).hom
⊢ i' = cmp ≫ pullback.fst αZ i

Tactic:
pullback.lift_fst

Goal state after:
C : Type u
inst✝² : Category.{v, u} C
W E X Z : C
c : BinaryCofan W E
inst✝¹ : FinitaryExtensive C
inst✝ : HasPullbacks C
hc : IsColimit c
f : W ⟶ X
h : X ⟶ Z
i : c.pt ⟶ Z
H : IsPushout f c.inl h i
hc₁ : IsColimit (BinaryCofan.mk (c.inr ≫ i) h)
W' X' Y' Z' : C
f' : W' ⟶ X'
g' : W' ⟶ Y'
h' : X' ⟶ Z'
i' : Y' ⟶ Z'
αW : W' ⟶ W
αX : X' ⟶ X
αY : Y' ⟶ ((Functor.const (Discrete WalkingPair)).obj c.pt).obj { as := WalkingPair.left }
αZ : Z' ⟶ Z
hf : IsPullback f' αW αX f
hg : IsPullback g' αW αY c.inl
hh : CommSq h' αX αZ h
hi : CommSq i' αY αZ i
w : CommSq f' g' h' i'
hc₂ : IsColimit (BinaryCofan.mk g' (pullback.fst αY c.inr))
hc₃ :
  IsPullback (BinaryCofan.mk ((BinaryCofan.mk g' (pullback.fst αY c.inr)).inr ≫ i') h').inl (pullback.snd αY c.inr) αZ
    (BinaryCofan.mk (c.inr ≫ i) h).inl
hc₄✝ :
  IsPullback (BinaryCofan.mk ((BinaryCofan.mk g' (pullback.fst αY c.inr)).inr ≫ i') h').inr αX αZ
    (BinaryCofan.mk (c.inr ≫ i) h).inr
Y'' : C := pullback αZ i
cmp : Y' ⟶ Y'' := pullback.lift i' αY ⋯
e₁ : (g' ≫ cmp) ≫ pullback.snd αZ i = αW ≫ c.inl
e₂ : (pullback.fst αY c.inr ≫ cmp) ≫ pullback.snd αZ i = pullback.snd αY c.inr ≫ c.inr
hc₄ : IsColimit (BinaryCofan.mk (g' ≫ cmp) (pullback.fst αY c.inr ≫ cmp))
this : cmp = (hc₂.coconePointUniqueUpToIso hc₄).hom
⊢ i' = i'
Module: Mathlib.CategoryTheory.Adhesive.Basic

Goal state before:
pp: case refine_2.mpr
C : Type u
inst✝² : Category.{v, u} C
W E X Z : C
c : BinaryCofan W E
inst✝¹ : FinitaryExtensive C
inst✝ : HasPullbacks C
hc : IsColimit c
f : W ⟶ X
h : X ⟶ Z
i : c.pt ⟶ Z
H : IsPushout f c.inl h i
hc₁ : IsColimit (BinaryCofan.mk (c.inr ≫ i) h)
W' X' Y' Z' : C
f' : W' ⟶ X'
g' : W' ⟶ Y'
h' : X' ⟶ Z'
i' : Y' ⟶ Z'
αW : W' ⟶ W
αX : X' ⟶ X
αY : Y' ⟶ ((Functor.const (Discrete WalkingPair)).obj c.pt).obj { as := WalkingPair.left }
αZ : Z' ⟶ Z
hf : IsPullback f' αW αX f
hg : IsPullback g' αW αY c.inl
hh : CommSq h' αX αZ h
hi : CommSq i' αY αZ i
w : CommSq f' g' h' i'
hc₂ : IsColimit (BinaryCofan.mk g' (pullback.fst αY c.inr))
⊢ IsPullback h' αX αZ h ∧ IsPullback i' αY αZ i →
    IsPullback (BinaryCofan.mk ((BinaryCofan.mk g' (pullback.fst αY c.inr)).inr ≫ i') h').inl (pullback.snd αY c.inr) αZ
        (BinaryCofan.mk (c.inr ≫ i) h).inl ∧
      IsPullback (BinaryCofan.mk ((BinaryCofan.mk g' (pullback.fst αY c.inr)).inr ≫ i') h').inr αX αZ
        (BinaryCofan.mk (c.inr ≫ i) h).inr

Tactic:
· rintro ⟨hc₃, hc₄⟩
    exact ⟨(IsPullback.of_hasPullback αY c.inr).paste_horiz hc₄, hc₃⟩

Goal state after:
Module: Mathlib.CategoryTheory.Limits.VanKampen

Goal state before:
pp: case refine_2
C : Type u
inst✝¹ : Category.{v, u} C
n : ℕ
f : Fin (n + 1) → C
c₁ : Cofan fun i ↦ f i.succ
c₂ : BinaryCofan (f 0) c₁.pt
t₁ : IsUniversalColimit c₁
t₂ : IsUniversalColimit c₂
inst✝ : ∀ {Z : C} (i : Z ⟶ c₂.pt), HasPullback c₂.inr i
F : Discrete (Fin (n + 1)) ⥤ C
c : Cocone F
α : F ⟶ Discrete.functor f
i : c.pt ⟶ (extendCofan c₁ c₂).pt
e : α ≫ (extendCofan c₁ c₂).ι = c.ι ≫ (const (Discrete (Fin (n + 1)))).map i
hα : NatTrans.Equifibered α
H : ∀ (j : Discrete (Fin (n + 1))), IsPullback (c.ι.app j) (α.app j) i ((extendCofan c₁ c₂).ι.app j)
F' : Fin (n + 1) → C := F.obj ∘ Discrete.mk
this : F = Discrete.functor F'
⊢ (Discrete.natTrans fun i ↦ α.app { as := i.as.succ }) ≫ c₁.ι =
    (Cofan.mk (pullback c₂.inr i) fun j ↦
          pullback.lift (α.app { as := j.succ } ≫ c₁.inj j) (c.ι.app { as := j.succ }) ⋯).ι ≫
      (const (Discrete (Fin n))).map (pullback.fst c₂.inr i)

Tactic:
ext j
    dsimp
    simp only [limit.lift_π, PullbackCone.mk_pt, PullbackCone.mk_π_app, Cofan.inj]

Goal state after:
Module: Mathlib.CategoryTheory.Limits.VanKampen

Goal state before:
pp: case refine_3
C : Type u
inst✝¹ : Category.{v, u} C
n : ℕ
f : Fin (n + 1) → C
c₁ : Cofan fun i ↦ f i.succ
c₂ : BinaryCofan (f 0) c₁.pt
t₁ : IsUniversalColimit c₁
t₂ : IsUniversalColimit c₂
inst✝ : ∀ {Z : C} (i : Z ⟶ c₂.pt), HasPullback c₂.inr i
F : Discrete (Fin (n + 1)) ⥤ C
c : Cocone F
α : F ⟶ Discrete.functor f
i : c.pt ⟶ (extendCofan c₁ c₂).pt
e : α ≫ (extendCofan c₁ c₂).ι = c.ι ≫ (const (Discrete (Fin (n + 1)))).map i
hα : NatTrans.Equifibered α
H : ∀ (j : Discrete (Fin (n + 1))), IsPullback (c.ι.app j) (α.app j) i ((extendCofan c₁ c₂).ι.app j)
F' : Fin (n + 1) → C := F.obj ∘ Discrete.mk
this : F = Discrete.functor F'
j : Discrete (Fin n)
⊢ IsPullback (pullback.lift (α.app { as := j.as.succ } ≫ c₁.inj j.as) (c.ι.app { as := j.as.succ }) ⋯)
    (α.app { as := j.as.succ }) (pullback.fst c₂.inr i) (c₁.ι.app j)

Tactic:
refine IsPullback.of_right ?_ ?_ (IsPullback.of_hasPullback (BinaryCofan.inr c₂) i).flip

Goal state after:
case refine_3.refine_1
C : Type u
inst✝¹ : Category.{v, u} C
n : ℕ
f : Fin (n + 1) → C
c₁ : Cofan fun i ↦ f i.succ
c₂ : BinaryCofan (f 0) c₁.pt
t₁ : IsUniversalColimit c₁
t₂ : IsUniversalColimit c₂
inst✝ : ∀ {Z : C} (i : Z ⟶ c₂.pt), HasPullback c₂.inr i
F : Discrete (Fin (n + 1)) ⥤ C
c : Cocone F
α : F ⟶ Discrete.functor f
i : c.pt ⟶ (extendCofan c₁ c₂).pt
e : α ≫ (extendCofan c₁ c₂).ι = c.ι ≫ (const (Discrete (Fin (n + 1)))).map i
hα : NatTrans.Equifibered α
H : ∀ (j : Discrete (Fin (n + 1))), IsPullback (c.ι.app j) (α.app j) i ((extendCofan c₁ c₂).ι.app j)
F' : Fin (n + 1) → C := F.obj ∘ Discrete.mk
this : F = Discrete.functor F'
j : Discrete (Fin n)
⊢ IsPullback
    (pullback.lift (α.app { as := j.as.succ } ≫ c₁.inj j.as) (c.ι.app { as := j.as.succ }) ⋯ ≫ pullback.snd c₂.inr i)
    (α.app { as := j.as.succ }) i (c₁.ι.app j ≫ c₂.inr)

case refine_3.refine_2
C : Type u
inst✝¹ : Category.{v, u} C
n : ℕ
f : Fin (n + 1) → C
c₁ : Cofan fun i ↦ f i.succ
c₂ : BinaryCofan (f 0) c₁.pt
t₁ : IsUniversalColimit c₁
t₂ : IsUniversalColimit c₂
inst✝ : ∀ {Z : C} (i : Z ⟶ c₂.pt), HasPullback c₂.inr i
F : Discrete (Fin (n + 1)) ⥤ C
c : Cocone F
α : F ⟶ Discrete.functor f
i : c.pt ⟶ (extendCofan c₁ c₂).pt
e : α ≫ (extendCofan c₁ c₂).ι = c.ι ≫ (const (Discrete (Fin (n + 1)))).map i
hα : NatTrans.Equifibered α
H : ∀ (j : Discrete (Fin (n + 1))), IsPullback (c.ι.app j) (α.app j) i ((extendCofan c₁ c₂).ι.app j)
F' : Fin (n + 1) → C := F.obj ∘ Discrete.mk
this : F = Discrete.functor F'
j : Discrete (Fin n)
⊢ pullback.lift (α.app { as := j.as.succ } ≫ c₁.inj j.as) (c.ι.app { as := j.as.succ }) ⋯ ≫ pullback.fst c₂.inr i =
    α.app { as := j.as.succ } ≫ c₁.ι.app j
Module: Mathlib.CategoryTheory.Sites.LocallyInjective

Goal state before:
pp: C : Type u
inst✝³ : Category.{v, u} C
D : Type u'
inst✝² : Category.{v', u'} D
FD : D → D → Type u_1
CD : D → Type w
inst✝¹ : (X Y : D) → FunLike (FD X Y) (CD X) (CD Y)
inst✝ : ConcreteCategory D FD
J : GrothendieckTopology C
F₁ F₂ F₃ : Cᵒᵖ ⥤ D
φ : F₁ ⟶ F₂
ψ : F₂ ⟶ F₃
F : Cᵒᵖ ⥤ Type w
G : Subfunctor F
X : Cᵒᵖ
⊢ Function.Injective ⇑(ConcreteCategory.hom (G.ι.app X))

Tactic:
by
    intro ⟨x, _⟩ ⟨y, _⟩ h
    exact Subtype.ext h

Goal state after:
Module: Mathlib.CategoryTheory.Limits.Bicones

Goal state before:
pp: J : Type u₁
inst✝ : Fintype J
j : Bicone J
⊢ j ∈ [Bicone.left, Bicone.right].toFinset ∪ Finset.image Bicone.diagram Fintype.elems

Tactic:
cases j

Goal state after:
case left
J : Type u₁
inst✝ : Fintype J
⊢ Bicone.left ∈ [Bicone.left, Bicone.right].toFinset ∪ Finset.image Bicone.diagram Fintype.elems

case right
J : Type u₁
inst✝ : Fintype J
⊢ Bicone.right ∈ [Bicone.left, Bicone.right].toFinset ∪ Finset.image Bicone.diagram Fintype.elems

case diagram
J : Type u₁
inst✝ : Fintype J
val✝ : J
⊢ Bicone.diagram val✝ ∈ [Bicone.left, Bicone.right].toFinset ∪ Finset.image Bicone.diagram Fintype.elems
Module: Mathlib.Algebra.Category.ModuleCat.Presheaf.Sheafify

Goal state before:
pp: C : Type u₁
inst✝⁷ : Category.{v₁, u₁} C
J : GrothendieckTopology C
R₀ : Cᵒᵖ ⥤ RingCat
R : Sheaf J RingCat
α : R₀ ⟶ R.obj
inst✝⁶ : Presheaf.IsLocallyInjective J α
inst✝⁵ : Presheaf.IsLocallySurjective J α
M₀ : PresheafOfModules R₀
A : Sheaf J AddCommGrpCat
φ : M₀.presheaf ⟶ A.obj
inst✝⁴ : Presheaf.IsLocallyInjective J φ
inst✝³ : Presheaf.IsLocallySurjective J φ
inst✝² : J.WEqualsLocallyBijective AddCommGrpCat
M₀' : PresheafOfModules R₀
A' : Sheaf J AddCommGrpCat
φ' : M₀'.presheaf ⟶ A'.obj
inst✝¹ : Presheaf.IsLocallyInjective J φ'
inst✝ : Presheaf.IsLocallySurjective J φ'
τ₀ : M₀ ⟶ M₀'
τ : A ⟶ A'
fac : (toPresheaf R₀).map τ₀ ≫ φ' = φ ≫ τ.hom
X : Cᵒᵖ
r : ↑(R.obj.obj X)
m : ↑((sheafify α φ).val.obj X)
f : (sheafify α φ).val ⟶ (sheafify α φ').val := (sheafifyHomEquiv' α φ ⋯).symm (τ₀ ≫ toSheafify α φ')
⊢ φ ≫ τ.hom = φ ≫ (toPresheaf R.obj).map ((sheafifyHomEquiv' α φ ⋯).symm (τ₀ ≫ toSheafify α φ'))

Tactic:
comp_toPresheaf_map_sheafifyHomEquiv'_symm_hom

Goal state after:
C : Type u₁
inst✝⁷ : Category.{v₁, u₁} C
J : GrothendieckTopology C
R₀ : Cᵒᵖ ⥤ RingCat
R : Sheaf J RingCat
α : R₀ ⟶ R.obj
inst✝⁶ : Presheaf.IsLocallyInjective J α
inst✝⁵ : Presheaf.IsLocallySurjective J α
M₀ : PresheafOfModules R₀
A : Sheaf J AddCommGrpCat
φ : M₀.presheaf ⟶ A.obj
inst✝⁴ : Presheaf.IsLocallyInjective J φ
inst✝³ : Presheaf.IsLocallySurjective J φ
inst✝² : J.WEqualsLocallyBijective AddCommGrpCat
M₀' : PresheafOfModules R₀
A' : Sheaf J AddCommGrpCat
φ' : M₀'.presheaf ⟶ A'.obj
inst✝¹ : Presheaf.IsLocallyInjective J φ'
inst✝ : Presheaf.IsLocallySurjective J φ'
τ₀ : M₀ ⟶ M₀'
τ : A ⟶ A'
fac : (toPresheaf R₀).map τ₀ ≫ φ' = φ ≫ τ.hom
X : Cᵒᵖ
r : ↑(R.obj.obj X)
m : ↑((sheafify α φ).val.obj X)
f : (sheafify α φ).val ⟶ (sheafify α φ').val := (sheafifyHomEquiv' α φ ⋯).symm (τ₀ ≫ toSheafify α φ')
⊢ φ ≫ τ.hom = (toPresheaf R₀).map (τ₀ ≫ toSheafify α φ')
Module: Mathlib.CategoryTheory.Limits.Bicones

Goal state before:
pp: J : Type v₁
inst✝¹ : SmallCategory J
inst✝ : FinCategory J
j k : Bicone J
⊢ Fintype (j ⟶ k)

Tactic:
cases j

Goal state after:
case left
J : Type v₁
inst✝¹ : SmallCategory J
inst✝ : FinCategory J
k : Bicone J
⊢ Fintype (Bicone.left ⟶ k)

case right
J : Type v₁
inst✝¹ : SmallCategory J
inst✝ : FinCategory J
k : Bicone J
⊢ Fintype (Bicone.right ⟶ k)

case diagram
J : Type v₁
inst✝¹ : SmallCategory J
inst✝ : FinCategory J
k : Bicone J
val✝ : J
⊢ Fintype (Bicone.diagram val✝ ⟶ k)
Module: Mathlib.CategoryTheory.Sites.Hypercover.Zero

Goal state before:
pp: C : Type u
inst✝² : Category.{v, u} C
S✝ T✝ : C
E✝ : PreZeroHypercover S✝
F : PreZeroHypercover S✝
S T : C
f : S ⟶ T
E : PreZeroHypercover T
inst✝¹ : ∀ (i : E.I₀), HasPullback f (E.f i)
inst✝ : ∀ (i : E.I₀), HasPullback (E.f i) f
⊢ { s₀ := id, h₀ := fun i ↦ (pullbackSymmetry f (E.f i)).hom, w₀ := ⋯ } ≫
      { s₀ := id, h₀ := fun i ↦ (pullbackSymmetry f (E.f i)).inv, w₀ := ⋯ } =
    𝟙 (pullback₁ f E)

Tactic:
apply Hom.ext (by rfl)

Goal state after:
C : Type u
inst✝² : Category.{v, u} C
S✝ T✝ : C
E✝ : PreZeroHypercover S✝
F : PreZeroHypercover S✝
S T : C
f : S ⟶ T
E : PreZeroHypercover T
inst✝¹ : ∀ (i : E.I₀), HasPullback f (E.f i)
inst✝ : ∀ (i : E.I₀), HasPullback (E.f i) f
⊢ ({ s₀ := id, h₀ := fun i ↦ (pullbackSymmetry f (E.f i)).hom, w₀ := ⋯ } ≫
        { s₀ := id, h₀ := fun i ↦ (pullbackSymmetry f (E.f i)).inv, w₀ := ⋯ }).h₀ ≍
    (𝟙 (pullback₁ f E)).h₀