mathlib-initiative/mathlib-tactics huggingface dataset:
Module: Mathlib.CategoryTheory.Presentable.CardinalDirectedPoset

Goal state before:
pp: κ : Cardinal.{u}
inst✝¹ : Fact κ.IsRegular
J : CardinalDirectedPoset κ
κ' : Cardinal.{u}
inst✝ : Fact κ'.IsRegular
hJ : HasCardinalLT (↑J.obj) κ'
h : κ ≤ κ'
A : Type u
x✝¹ : SmallCategory A
x✝ : IsCardinalFiltered A κ'
F : A ⥤ CardinalDirectedPoset κ
c : Cocone F
this✝ : IsFiltered A
this : IsCardinalFiltered A κ
hc : IsColimit ((forget (CardinalDirectedPoset κ)).mapCocone c)
f : J ⟶ c.pt
j : ↑J.obj → A
g : (x : ↑J.obj) → (fun X ↦ X) ((F ⋙ forget (CardinalDirectedPoset κ)).obj (j x))
hg :
  ∀ (x : ↑J.obj),
    (ConcreteCategory.hom (((forget (CardinalDirectedPoset κ)).mapCocone c).ι.app (j x))) (g x) =
      (ConcreteCategory.hom f) x
m : A := ⋯
φ : ↑J.obj → ↑(F.obj m).obj := ⋯
hφ : ∀ (x : ↑J.obj), (ConcreteCategory.hom f) x = (ConcreteCategory.hom (c.ι.app m)) (φ x)
x : ↑J.obj
⊢ (PartOrdEmb.Hom.hom f.hom) x = (ConcreteCategory.hom (c.ι.app (j x))) (g x)

Tactic:
exact (hg x).symm

Goal state after:
Module: Mathlib.CategoryTheory.Presentable.CardinalDirectedPoset

Goal state before:
pp: κ : Cardinal.{u}
inst✝¹ : Fact κ.IsRegular
J : CardinalDirectedPoset κ
κ' : Cardinal.{u}
inst✝ : Fact κ'.IsRegular
hJ : HasCardinalLT (↑J.obj) κ'
h : κ ≤ κ'
A : Type u
x✝¹ : SmallCategory A
x✝ : IsCardinalFiltered A κ'
F : A ⥤ CardinalDirectedPoset κ
c : Cocone F
hc : IsColimit c
⊢ IsColimit ((coyoneda.obj (Opposite.op J)).mapCocone c)

Tactic:
have := isFiltered_of_isCardinalFiltered A κ'
    have := IsCardinalFiltered.of_le A h
    replace hc := isColimitOfPreserves (forget _) hc
    refine Types.FilteredColimit.isColimitOf' _ _ (fun f ↦ ?_) (fun j f g h ↦ ?_)
    · dsimp at f
      choose j g hg using fun (x : J.obj) ↦ Types.jointly_surjective_of_isColimit hc (f x)
      let m := IsCardinalFiltered.max j hJ
      let φ (x : J.obj) : (F.obj m).obj := F.map (IsCardinalFiltered.toMax j hJ x) (g x)
      have hφ (x : J.obj) : f x = c.ι.app _ (φ x) := by
        dsimp [φ]
        rw [← hg, ← ConcreteCategory.comp_apply, c.w]
        rfl
      refine ⟨m,
        ObjectProperty.homMk (PartOrdEmb.ofHom
          { toFun := φ
            inj' x y h := Hom.injective f (by simpa [hφ])
            map_rel_iff' {x y} := ?_ }), ?_⟩
      · simp [← Hom.le_iff_le f, hφ]
      · dsimp
        ext x
        trans c.ι.app (j x) (g x)
        · exact (hg x).symm
        · exact (ConcreteCategory.congr_hom (c.w (IsCardinalFiltered.toMax j hJ x)).symm (g x))
    · choose k a hk using fun (x : J.obj) ↦
        (Types.FilteredColimit.isColimit_eq_iff' hc _ _).1 (ConcreteCategory.congr_hom h x)
      dsimp at f g h k a hk ⊢
      obtain ⟨l, b, c, hl⟩ : ∃ (l : A) (c : j ⟶ l) (b : ∀ x, k x ⟶ l),
          ∀ x, a x ≫ b x = c := by
        let φ (x : J.obj) : j ⟶ IsCardinalFiltered.max k hJ :=
          a x ≫ IsCardinalFiltered.toMax k hJ x
        exact ⟨IsCardinalFiltered.coeq φ hJ,
          IsCardinalFiltered.toCoeq φ hJ,
          fun x ↦ IsCardinalFiltered.toMax k hJ x ≫ IsCardinalFiltered.coeqHom φ hJ,
          fun x ↦ by simpa [φ] using IsCardinalFiltered.coeq_condition φ hJ x⟩
      refine ⟨l, b, ?_⟩
      ext x
      simpa only [← hl x, Functor.map_comp, ObjectProperty.FullSubcategory.comp_hom,
        PartOrdEmb.hom_comp, RelEmbedding.coe_trans, Function.comp_apply]
          using! congr_arg _ (hk x)

Goal state after:
Module: Mathlib.CategoryTheory.Presentable.SharplyLT.Basic

Goal state before:
pp: κ₁ κ₂ : Cardinal.{w}
inst✝² : Fact κ₁.IsRegular
inst✝¹ : Fact κ₂.IsRegular
h : κ₁ ≤ κ₂
inst✝ : IsCardinalAccessibleCategory (CardinalDirectedPoset κ₁) κ₂
X : Type w
hX : HasCardinalLT X κ₂
J : Type w
w✝¹ : SmallCategory J
w✝ : IsCardinalFiltered J κ₂
p : (isCardinalPresentable (CardinalDirectedPoset κ₁) κ₂).ColimitOfShape J (setCardinalLT κ₁ X)
this : IsCardinalFiltered J κ₁
hp : ∀ (j : J), HasCardinalLT (↑(p.diag.obj j).obj) κ₂
j : X → J
y : (x : X) → ToType (p.diag.obj (j x))
hy : ∀ (x : X), (ConcreteCategory.hom (p.ι.app (j x))) (y x) = SetCardinalLT.singleton κ₁ x
j' : J := IsCardinalFiltered.max j hX
y' : X → ↑(p.diag.obj j').obj := fun x ↦ (ConcreteCategory.hom (p.diag.map (IsCardinalFiltered.toMax j hX x))) (y x)
x : X
⊢ (ConcreteCategory.hom (p.ι.app j')) (y' x) = SetCardinalLT.singleton κ₁ x

Tactic:
rw [← hy, ← p.w (IsCardinalFiltered.toMax j hX x)]

Goal state after:
κ₁ κ₂ : Cardinal.{w}
inst✝² : Fact κ₁.IsRegular
inst✝¹ : Fact κ₂.IsRegular
h : κ₁ ≤ κ₂
inst✝ : IsCardinalAccessibleCategory (CardinalDirectedPoset κ₁) κ₂
X : Type w
hX : HasCardinalLT X κ₂
J : Type w
w✝¹ : SmallCategory J
w✝ : IsCardinalFiltered J κ₂
p : (isCardinalPresentable (CardinalDirectedPoset κ₁) κ₂).ColimitOfShape J (setCardinalLT κ₁ X)
this : IsCardinalFiltered J κ₁
hp : ∀ (j : J), HasCardinalLT (↑(p.diag.obj j).obj) κ₂
j : X → J
y : (x : X) → ToType (p.diag.obj (j x))
hy : ∀ (x : X), (ConcreteCategory.hom (p.ι.app (j x))) (y x) = SetCardinalLT.singleton κ₁ x
j' : J := IsCardinalFiltered.max j hX
y' : X → ↑(p.diag.obj j').obj := fun x ↦ (ConcreteCategory.hom (p.diag.map (IsCardinalFiltered.toMax j hX x))) (y x)
x : X
⊢ (ConcreteCategory.hom (p.ι.app j')) (y' x) =
    (ConcreteCategory.hom (p.diag.map (IsCardinalFiltered.toMax j hX x) ≫ p.ι.app (IsCardinalFiltered.max j hX))) (y x)
Module: Mathlib.CategoryTheory.Presentable.Type

Goal state before:
pp: case refine_1
X : Type u
κ : Cardinal.{u}
hX : HasCardinalLT X κ
inst✝ : Fact κ.IsRegular
J : Type u
x✝¹ : SmallCategory J
x✝ : IsCardinalFiltered J κ
F : J ⥤ Type u
c : Cocone F
hc : IsColimit c
this : IsFiltered J
f : ((coyoneda.obj (op X)).mapCocone c).pt
⊢ ∃ i xi, f = (hom (((coyoneda.obj (op X)).mapCocone c).ι.app i)) xi

Tactic:
dsimp at f

Goal state after:
case refine_1
X : Type u
κ : Cardinal.{u}
hX : HasCardinalLT X κ
inst✝ : Fact κ.IsRegular
J : Type u
x✝¹ : SmallCategory J
x✝ : IsCardinalFiltered J κ
F : J ⥤ Type u
c : Cocone F
hc : IsColimit c
this : IsFiltered J
f : X ⟶ c.pt
⊢ ∃ i xi, f = (hom (((coyoneda.obj (op X)).mapCocone c).ι.app i)) xi
Module: Mathlib.CategoryTheory.Presentable.Directed

Goal state before:
pp: case refine_2.inr
J : Type w
inst✝² : SmallCategory J
κ : Cardinal.{w}
inst✝¹ : Fact κ.IsRegular
inst✝ : IsCardinalFiltered J κ
hJ : ∀ (e : J), ∃ m x, IsEmpty (m ⟶ e)
ι : Type w
D : ι → DiagramWithUniqueTerminal J κ
hι : HasCardinalLT ι κ
m : J
u : (i : ι) → (D i).top ⟶ m
hm₀ : ∀ (i : ι), IsEmpty (m ⟶ (D i).top)
hm :
  ∀ (i₁ i₂ : ι) (j : J) (hj₁ : (D i₁).P j) (hj₂ : (D i₂).P j),
    (D i₁).isTerminal.lift hj₁ ≫ u i₁ = (D i₂).isTerminal.lift hj₂ ≫ u i₂
φ : (x : (i : ι) × Subtype (D i).P) → ↑x.snd ⟶ m := fun x ↦ (D x.fst).isTerminal.lift ⋯ ≫ u x.fst
hD : ∀ {i : ι}, ¬(D i).P m
H : ∀ {i : ι} {j : J} (hj : (D i).P j) {f : j ⟶ m}, (D₂ D hι u).W f → f = φ ⟨i, ⟨j, hj⟩⟩
⊢ ∃ lift,
    (((⨆ i, (D i).W) ⊔ MorphismProperty.ofHoms fun x ↦ 𝟙 m) ⊔
        MorphismProperty.ofHoms fun x ↦ (D x.fst).isTerminal.lift ⋯ ≫ u x.fst)
      lift

Tactic:
· exact ⟨𝟙 _, Or.inl (Or.inr ⟨⟨⟩⟩)⟩

Goal state after:
Module: Mathlib.CategoryTheory.Sites.Adjunction

Goal state before:
pp: case e'_3
C : Type u₁
inst✝² : Category.{v₁, u₁} C
J : GrothendieckTopology C
D : Type u₂
inst✝¹ : Category.{v₂, u₂} D
E : Type u_1
inst✝ : Category.{v_1, u_1} E
F : D ⥤ E
G : E ⥤ D
adj : G ⊣ F
P Q : Cᵒᵖ ⥤ E
f : P ⟶ Q
hf : J.W f
this : F.IsRightAdjoint
R : Cᵒᵖ ⥤ D
hR : Presheaf.IsSheaf J R
e_1✝ : (Q ⋙ G ⟶ R) = (((whiskeringRight Cᵒᵖ E D).obj G).obj Q ⟶ R)
e_2✝ : (P ⟶ ((whiskeringRight Cᵒᵖ D E).obj F).obj R) = (P ⟶ R ⋙ F)
⊢ (⇑((Adjunction.whiskerRight Cᵒᵖ adj).homEquiv P R) ∘ fun g ↦ whiskerRight f G ≫ g) =
    ⇑(((Adjunction.whiskerRight Cᵒᵖ adj).homEquiv Q R).trans (ObjectProperty.isLocal.homEquiv hf (R ⋙ F) ⋯))

Tactic:
ext g X

Goal state after:
case e'_3
C : Type u₁
inst✝² : Category.{v₁, u₁} C
J : GrothendieckTopology C
D : Type u₂
inst✝¹ : Category.{v₂, u₂} D
E : Type u_1
inst✝ : Category.{v_1, u_1} E
F : D ⥤ E
G : E ⥤ D
adj : G ⊣ F
P Q : Cᵒᵖ ⥤ E
f : P ⟶ Q
hf : J.W f
this : F.IsRightAdjoint
R : Cᵒᵖ ⥤ D
hR : Presheaf.IsSheaf J R
e_1✝ : (Q ⋙ G ⟶ R) = (((whiskeringRight Cᵒᵖ E D).obj G).obj Q ⟶ R)
e_2✝ : (P ⟶ ((whiskeringRight Cᵒᵖ D E).obj F).obj R) = (P ⟶ R ⋙ F)
g : Q ⋙ G ⟶ R
X : Cᵒᵖ
⊢ ((⇑((Adjunction.whiskerRight Cᵒᵖ adj).homEquiv P R) ∘ fun g ↦ whiskerRight f G ≫ g) g).app X =
    ((((Adjunction.whiskerRight Cᵒᵖ adj).homEquiv Q R).trans (ObjectProperty.isLocal.homEquiv hf (R ⋙ F) ⋯)) g).app X
Module: Mathlib.CategoryTheory.Presentable.Directed

Goal state before:
pp: case inr
J : Type w
inst✝² : SmallCategory J
κ : Cardinal.{w}
inst✝¹ : Fact κ.IsRegular
inst✝ : IsCardinalFiltered J κ
hJ : ∀ (e : J), ∃ m x, IsEmpty (m ⟶ e)
this✝¹ : IsCardinalFiltered (DiagramWithUniqueTerminal J κ) κ
this✝ : IsFiltered J
this : IsFiltered (DiagramWithUniqueTerminal J κ)
j : J
D : DiagramWithUniqueTerminal J κ
f₁ f₂ : j ⟶ D.top
m₀ : J
t : D.top ⟶ m₀
hm₀ : IsEmpty (m₀ ⟶ D.top)
m₁ : J
u : m₀ ⟶ m₁
hu : f₁ ≫ t ≫ u = f₂ ≫ t ≫ u
h₁ : ¬D.P m₁
φ : (x : Subtype D.P) → ↑x ⟶ m₁ := fun x ↦ D.isTerminal.lift ⋯ ≫ t ≫ u
h₂ : ∀ {j : J} (hj : D.P j) {f : j ⟶ m₁}, (D₄ D φ).W f → f = φ ⟨j, hj⟩
h₃ : ∀ {f : m₁ ⟶ m₁}, (D₄ D φ).W f → f = 𝟙 m₁
⊢ ∃ lift, (D₄ D φ).W lift

Tactic:
· exact ⟨𝟙 _, Or.inl (Or.inr ⟨⟨⟩⟩)⟩

Goal state after:
Module: Mathlib.CategoryTheory.Sites.Coherent.ExtensiveSheaves

Goal state before:
pp: case mpr
C : Type u_1
inst✝³ : Category.{v_1, u_1} C
D : Type u_2
inst✝² : Category.{v_2, u_2} D
inst✝¹ : FinitaryPreExtensive C
inst✝ : FinitaryExtensive C
F : Cᵒᵖ ⥤ D
a✝ : PreservesFiniteProducts F
⊢ IsSheaf (extensiveTopology C) F

Tactic:
E

Goal state after:
case mpr
C : Type u_1
inst✝³ : Category.{v_1, u_1} C
D : Type u_2
inst✝² : Category.{v_2, u_2} D
inst✝¹ : FinitaryPreExtensive C
inst✝ : FinitaryExtensive C
F : Cᵒᵖ ⥤ D
a✝ : PreservesFiniteProducts F
E : D
⊢ Presieve.IsSheaf (extensiveTopology C) (F ⋙ coyoneda.obj (op E))
Module: Mathlib.CategoryTheory.Sites.Coherent.SheafComparison

Goal state before:
pp: case refine_2.refine_2
C : Type u_1
D : Type u_2
inst✝⁷ : Category.{v_1, u_1} C
inst✝⁶ : Category.{v_2, u_2} D
F : C ⥤ D
inst✝⁵ : F.PreservesFiniteEffectiveEpiFamilies
inst✝⁴ : F.ReflectsFiniteEffectiveEpiFamilies
inst✝³ : F.Full
inst✝² : F.Faithful
inst✝¹ : F.EffectivelyEnough
inst✝ : Precoherent D
X : C
S : Sieve X
hS : Sieve.functorPushforward F S ∈ (coherentTopology D) (F.obj X)
α : Type
w✝ : Finite α
Y : α → D
π : (a : α) → Y a ⟶ F.obj X
H₁ : EffectiveEpiFamily Y π
H₂ : ∀ (a : α), (Sieve.functorPushforward F S).arrows (π a)
Z : α → C := fun a ↦ ⋯.some.p
g₀ : (a : α) → F.obj (Z a) ⟶ Y a := fun a ↦ F.effectiveEpiOver (Y a)
this : EffectiveEpiFamily (fun a ↦ F.obj (Z a)) fun a ↦ g₀ a ≫ π a
a : α
⊢ S.arrows (F.preimage (g₀ a ≫ π a))

Tactic:
· obtain ⟨W, g₁, g₂, h₁, h₂⟩ := H₂ a
      rw [h₂]
      convert! S.downward_closed h₁ (F.preimage (g₀ a ≫ g₂))
      exact F.map_injective (by simp)

Goal state after:
Module: Mathlib.CategoryTheory.Sites.Coherent.RegularSheaves

Goal state before:
pp: case refine_2
C : Type u_1
inst✝¹ : Category.{v_1, u_1} C
P : Cᵒᵖ ⥤ Type u_4
X B : C
π : X ⟶ B
inst✝ : EffectiveEpi π
c : PullbackCone π π
hc : IsLimit c
this : HasPullback π π
hP :
  ∀
    (b :
      (fun X ↦ X)
        ↑{x |
            (ConcreteCategory.hom (P.map (pullback.fst π π).op)) x =
              (ConcreteCategory.hom (P.map (pullback.snd π π).op)) x}),
    ∃! a, (ConcreteCategory.hom (mapToEqualizer P π (pullback.fst π π) (pullback.snd π π) ⋯)) a = b
b : P.obj (op X)
hb : (ConcreteCategory.hom (P.map c.fst.op)) b = (ConcreteCategory.hom (P.map c.snd.op)) b
h₁ : ((pullbackIsPullback π π).conePointUniqueUpToIso hc).hom ≫ c.fst = pullback.fst π π
hb' : (ConcreteCategory.hom (P.map (pullback.fst π π).op)) b = (ConcreteCategory.hom (P.map (pullback.snd π π).op)) b
a : P.obj (op B)
ha₁ : (ConcreteCategory.hom (mapToEqualizer P π (pullback.fst π π) (pullback.snd π π) ⋯)) a = ⟨b, hb'⟩
ha₂ :
  ∀ (y : (fun X ↦ X) (P.obj (op B))),
    (fun a ↦ (ConcreteCategory.hom (mapToEqualizer P π (pullback.fst π π) (pullback.snd π π) ⋯)) a = ⟨b, hb'⟩) y → y = a
⊢ ∀ (y : P.obj (op B)), (fun x ↦ (ConcreteCategory.hom (P.map π.op)) x = b) y → y = a

Tactic:
simpa [mapToEqualizer] using ha₂

Goal state after:
Module: Mathlib.CategoryTheory.Sites.Coherent.LocallySurjective

Goal state before:
pp: case e'_2
C : Type u_1
inst✝⁴ : Category.{v_1, u_1} C
inst✝³ : Preregular C
inst✝² : FinitaryPreExtensive C
F G : Cᵒᵖ ⥤ Type w
f : F ⟶ G
inst✝¹ : PreservesFiniteProducts F
inst✝ : PreservesFiniteProducts G
U✝ : C
y : ToType (G.obj (op U✝))
α : Type
w✝ : Finite α
Z : α → C
π : (a : α) → Z a ⟶ U✝
h : EffectiveEpiFamily Z π
h' : ∀ (a : α), (Presheaf.imageSieve f y).arrows (π a)
x : (a : α) → F.obj (op (Z a)) := fun a ↦ Exists.choose ⋯
i' : ((a : α) → F.obj (op (Z a))) ≅ F.obj (op (∐ Z)) :=
  (Types.productIso fun a ↦ F.obj (op (Z a))).symm ≪≫
    (PreservesProduct.iso F fun a ↦ op (Z a)).symm ≪≫ F.mapIso (opCoproductIsoProduct Z).symm
this✝¹ : PreservesLimitsOfShape (Discrete α)ᵒᵖ G
a : α
this✝ : (ConcreteCategory.hom (f.app (op (Z a)))) (x a) = (ConcreteCategory.hom (G.map (π a).op)) y
this : ((Types.productIso fun a ↦ F.obj (op (Z a))).hom ≫ ↾fun f ↦ f a) = Pi.π (fun a ↦ F.obj (op (Z a))) a
⊢ (ConcreteCategory.hom ((PreservesProduct.iso F fun x ↦ op (Z x)).hom ≫ Pi.π (fun b ↦ F.obj (op (Z b))) a))
      ((ConcreteCategory.hom (PreservesProduct.iso F fun a ↦ op (Z a)).inv)
        ((ConcreteCategory.hom (Types.productIso fun a ↦ F.obj (op (Z a))).inv) x)) =
    x a

Tactic:
← Iso.eq_inv_comp

Goal state after:
case e'_2
C : Type u_1
inst✝⁴ : Category.{v_1, u_1} C
inst✝³ : Preregular C
inst✝² : FinitaryPreExtensive C
F G : Cᵒᵖ ⥤ Type w
f : F ⟶ G
inst✝¹ : PreservesFiniteProducts F
inst✝ : PreservesFiniteProducts G
U✝ : C
y : ToType (G.obj (op U✝))
α : Type
w✝ : Finite α
Z : α → C
π : (a : α) → Z a ⟶ U✝
h : EffectiveEpiFamily Z π
h' : ∀ (a : α), (Presheaf.imageSieve f y).arrows (π a)
x : (a : α) → F.obj (op (Z a)) := fun a ↦ Exists.choose ⋯
i' : ((a : α) → F.obj (op (Z a))) ≅ F.obj (op (∐ Z)) :=
  (Types.productIso fun a ↦ F.obj (op (Z a))).symm ≪≫
    (PreservesProduct.iso F fun a ↦ op (Z a)).symm ≪≫ F.mapIso (opCoproductIsoProduct Z).symm
this✝¹ : PreservesLimitsOfShape (Discrete α)ᵒᵖ G
a : α
this✝ : (ConcreteCategory.hom (f.app (op (Z a)))) (x a) = (ConcreteCategory.hom (G.map (π a).op)) y
this : (↾fun f ↦ f a) = (Types.productIso fun a ↦ F.obj (op (Z a))).inv ≫ Pi.π (fun a ↦ F.obj (op (Z a))) a
⊢ (ConcreteCategory.hom ((PreservesProduct.iso F fun x ↦ op (Z x)).hom ≫ Pi.π (fun b ↦ F.obj (op (Z b))) a))
      ((ConcreteCategory.hom (PreservesProduct.iso F fun a ↦ op (Z a)).inv)
        ((ConcreteCategory.hom (Types.productIso fun a ↦ F.obj (op (Z a))).inv) x)) =
    x a
Module: Mathlib.CategoryTheory.Sites.Descent.Precoverage

Goal state before:
pp: C : Type u
inst✝ : Category.{v, u} C
F : LocallyDiscrete Cᵒᵖ ⥤ᵖ Cat
ι : Type t
S : C
X : ι → C
f : (i : ι) → X i ⟶ S
ι' : Type t'
X' : ι' → C
f' : (j : ι') → X' j ⟶ S
α : ι' → ι
p' : (j : ι') → X' j ⟶ X (α j)
w : ∀ (j : ι'), p' j ≫ f (α j) = f' j
D₁ D₂ : F.DescentData f
φ : (pullFunctor F ⋯).obj D₁ ⟶ (pullFunctor F ⋯).obj D₂
i : ι
Y₁ Y₂ Z : Over (X i)
h₂ : (sieve f f' i).arrows (Over.homMk Y₂.hom ⋯)
g₁ : Z.left ⟶ Y₁.left
hg₁ : g₁ ≫ Y₁.hom = Z.hom
g₂ : Z.left ⟶ Y₂.left
hg₂ : g₂ ≫ Y₂.hom = Z.hom
fac : Over.homMk g₁ ⋯ ≫ Over.homMk Y₁.hom ⋯ = Over.homMk g₂ ⋯ ≫ Over.homMk Y₂.hom ⋯
Y : C
j₁ : ι'
a₁ : (Over.forget (X i)).obj Y₁ ⟶ X' j₁
fac₁ : a₁ ≫ f' j₁ = (Over.forget (X i)).map (Over.homMk Y₁.hom ⋯) ≫ f i
⊢ (ConcreteCategory.hom ((F.presheafHom (D₁.obj i) (D₂.obj i)).map (Over.homMk g₁ ⋯).op))
      (familyOfElements w φ i (Over.homMk Y₁.hom ⋯) ⋯) =
    (ConcreteCategory.hom ((F.presheafHom (D₁.obj i) (D₂.obj i)).map (Over.homMk g₂ ⋯).op))
      (familyOfElements w φ i (Over.homMk Y₂.hom ⋯) h₂)

Tactic:
obtain ⟨_, a₂, _, ⟨j₂⟩, fac₂⟩ := h₂

Goal state after:
C : Type u
inst✝ : Category.{v, u} C
F : LocallyDiscrete Cᵒᵖ ⥤ᵖ Cat
ι : Type t
S : C
X : ι → C
f : (i : ι) → X i ⟶ S
ι' : Type t'
X' : ι' → C
f' : (j : ι') → X' j ⟶ S
α : ι' → ι
p' : (j : ι') → X' j ⟶ X (α j)
w : ∀ (j : ι'), p' j ≫ f (α j) = f' j
D₁ D₂ : F.DescentData f
φ : (pullFunctor F ⋯).obj D₁ ⟶ (pullFunctor F ⋯).obj D₂
i : ι
Y₁ Y₂ Z : Over (X i)
g₁ : Z.left ⟶ Y₁.left
hg₁ : g₁ ≫ Y₁.hom = Z.hom
g₂ : Z.left ⟶ Y₂.left
hg₂ : g₂ ≫ Y₂.hom = Z.hom
fac : Over.homMk g₁ ⋯ ≫ Over.homMk Y₁.hom ⋯ = Over.homMk g₂ ⋯ ≫ Over.homMk Y₂.hom ⋯
Y✝ : C
j₁ : ι'
a₁ : (Over.forget (X i)).obj Y₁ ⟶ X' j₁
fac₁ : a₁ ≫ f' j₁ = (Over.forget (X i)).map (Over.homMk Y₁.hom ⋯) ≫ f i
Y : C
j₂ : ι'
a₂ : (Over.forget (X i)).obj Y₂ ⟶ X' j₂
fac₂ : a₂ ≫ f' j₂ = (Over.forget (X i)).map (Over.homMk Y₂.hom ⋯) ≫ f i
⊢ (ConcreteCategory.hom ((F.presheafHom (D₁.obj i) (D₂.obj i)).map (Over.homMk g₁ ⋯).op))
      (familyOfElements w φ i (Over.homMk Y₁.hom ⋯) ⋯) =
    (ConcreteCategory.hom ((F.presheafHom (D₁.obj i) (D₂.obj i)).map (Over.homMk g₂ ⋯).op))
      (familyOfElements w φ i (Over.homMk Y₂.hom ⋯) ⋯)
Module: Mathlib.CategoryTheory.Sites.SheafHom

Goal state before:
pp: case mpr
C : Type u
inst✝¹ : Category.{v, u} C
A : Type u'
inst✝ : Category.{v', u'} A
F G : Cᵒᵖ ⥤ A
X : C
S : Sieve X
x : Presieve.FamilyOfElements (presheafHom F G) S.arrows
hx : x.Compatible
y : (presheafHom F G).obj (op X)
⊢ (∀ (Y : C) (g : Y ⟶ X) (hg : S.arrows g), y.app (op (Over.mk g)) = (x g hg).app (op (Over.mk (𝟙 Y)))) →
    x.IsAmalgamation y

Tactic:
intro h Y g hg
    dsimp
    ext ⟨W : Over Y⟩
    refine (h W.left (W.hom ≫ g) (S.downward_closed hg _)).trans ?_
    have H := hx (𝟙 _) W.hom (S.downward_closed hg W.hom) hg (by simp)
    simp only [op_id, Functor.map_id, id_apply] at H
    rw [H, presheafHom_map_app _ _ W.hom (by simp)]
    rfl

Goal state after:
Module: Mathlib.CategoryTheory.Sites.Descent.Precoverage

Goal state before:
pp: C : Type u
inst✝¹ : Category.{v, u} C
F : LocallyDiscrete Cᵒᵖ ⥤ᵖ Cat
J : GrothendieckTopology C
inst✝ : F.IsPrestack J
ι : Type t
S : C
X : ι → C
f : (i : ι) → X i ⟶ S
ι' : Type t'
X' : ι' → C
f' : (j : ι') → X' j ⟶ S
α : ι' → ι
p' : (j : ι') → X' j ⟶ X (α j)
w : ∀ (j : ι'), p' j ≫ f (α j) = f' j
hf' : Sieve.ofArrows X' f' ∈ J S
⊢ (pullFunctor F ⋯).FullyFaithful

Tactic:
have := faithful_pullFunctor F w hf'
  have := full_pullFunctor F w hf'
  exact .ofFullyFaithful _

Goal state after:
Module: Mathlib.CategoryTheory.Sites.Point.Monoidal

Goal state before:
pp: C : Type u
inst✝³ : Category.{v, u} C
J : GrothendieckTopology C
Φ : J.Point
A : Type u'
inst✝² : Category.{v', u'} A
inst✝¹ : MonoidalCategory A
inst✝ : HasColimitsOfSize.{w, w, v', u'} A
x✝ : Cᵒᵖ ⥤ A
⊢ (λ_ (Φ.presheafFiber.obj x✝)).inv =
    Φ.presheafFiber.map (λ_ x✝).inv ≫
      Φ.presheafFiberDesc (fun X x ↦ Φ.toPresheafFiber X x (𝟙_ (Cᵒᵖ ⥤ A)) ⊗ₘ Φ.toPresheafFiber X x x✝) ⋯ ≫
        Φ.presheafFiberDesc (fun x x_1 ↦ 𝟙 ((𝟙_ (Cᵒᵖ ⥤ A)).obj (Opposite.op x))) ⋯ ▷ Φ.presheafFiber.obj x✝

Tactic:
ext
    simp [tensorHom_def', ← comp_whiskerRight]

Goal state after:
Module: Mathlib.CategoryTheory.Sites.RegularEpi

Goal state before:
pp: C : Type u_1
D : Type u_2
inst✝⁶ : Category.{u_3, u_1} C
inst✝⁵ : Category.{u_4, u_2} D
J : GrothendieckTopology C
inst✝⁴ : HasPullbacks D
inst✝³ : HasPushouts D
inst✝² : IsRegularEpiCategory D
h : ∀ {F G : Sheaf J D} (f : F ⟶ G) [Epi f], ∃ I p i, Epi p ∧ Mono i ∧ p ≫ i = f.hom
inst✝¹ : HasSheafify J D
inst✝ : Balanced (Sheaf J D)
F G : Sheaf J D
f : F ⟶ G
x✝ : Epi f
I : Cᵒᵖ ⥤ D
p : F.obj ⟶ I
i : I ⟶ G.obj
hp : Epi p
hi : Mono i
hpi : p ≫ i = f.hom
h₁ :
  (presheafToSheaf J D).map f.hom =
    (sheafificationAdjunction J D).counit.app F ≫ f ≫ inv ((sheafificationAdjunction J D).counit.app G)
h₂ :
  f =
    inv ((sheafificationAdjunction J D).counit.app F) ≫
      (presheafToSheaf J D).map f.hom ≫ (sheafificationAdjunction J D).counit.app G
this : Epi ((presheafToSheaf J D).map (p ≫ i))
⊢ Epi ((presheafToSheaf J D).map i)

Tactic:
Functor.map_comp

Goal state after:
C : Type u_1
D : Type u_2
inst✝⁶ : Category.{u_3, u_1} C
inst✝⁵ : Category.{u_4, u_2} D
J : GrothendieckTopology C
inst✝⁴ : HasPullbacks D
inst✝³ : HasPushouts D
inst✝² : IsRegularEpiCategory D
h : ∀ {F G : Sheaf J D} (f : F ⟶ G) [Epi f], ∃ I p i, Epi p ∧ Mono i ∧ p ≫ i = f.hom
inst✝¹ : HasSheafify J D
inst✝ : Balanced (Sheaf J D)
F G : Sheaf J D
f : F ⟶ G
x✝ : Epi f
I : Cᵒᵖ ⥤ D
p : F.obj ⟶ I
i : I ⟶ G.obj
hp : Epi p
hi : Mono i
hpi : p ≫ i = f.hom
h₁ :
  (presheafToSheaf J D).map f.hom =
    (sheafificationAdjunction J D).counit.app F ≫ f ≫ inv ((sheafificationAdjunction J D).counit.app G)
h₂ :
  f =
    inv ((sheafificationAdjunction J D).counit.app F) ≫
      (presheafToSheaf J D).map f.hom ≫ (sheafificationAdjunction J D).counit.app G
this : Epi ((presheafToSheaf J D).map p ≫ (presheafToSheaf J D).map i)
⊢ Epi ((presheafToSheaf J D).map i)
Module: Mathlib.CategoryTheory.Sites.RegularEpi

Goal state before:
pp: C : Type u_1
D : Type u_2
inst✝⁶ : Category.{u_3, u_1} C
inst✝⁵ : Category.{u_4, u_2} D
J : GrothendieckTopology C
inst✝⁴ : HasPullbacks D
inst✝³ : HasPushouts D
inst✝² : IsRegularEpiCategory D
h : ∀ {F G : Sheaf J D} (f : F ⟶ G) [Epi f], ∃ I p i, Epi p ∧ Mono i ∧ p ≫ i = f.hom
inst✝¹ : HasSheafify J D
inst✝ : Balanced (Sheaf J D)
F G : Sheaf J D
f : F ⟶ G
x✝ : Epi f
I : Cᵒᵖ ⥤ D
p : F.obj ⟶ I
i : I ⟶ G.obj
hp : Epi p
hi : Mono i
hpi : p ≫ i = f.hom
h₁ :
  (presheafToSheaf J D).map f.hom =
    (sheafificationAdjunction J D).counit.app F ≫ f ≫ inv ((sheafificationAdjunction J D).counit.app G)
h₂ :
  f =
    inv ((sheafificationAdjunction J D).counit.app F) ≫
      (presheafToSheaf J D).map f.hom ≫ (sheafificationAdjunction J D).counit.app G
this : Epi ((presheafToSheaf J D).map p ≫ (presheafToSheaf J D).map i)
⊢ Epi ((presheafToSheaf J D).map i)

Tactic:
exact epi_of_epi ((presheafToSheaf J D).map p) _

Goal state after:
Module: Mathlib.CategoryTheory.Sites.RegularEpi

Goal state before:
pp: C : Type u_1
D : Type u_2
inst✝⁶ : Category.{u_3, u_1} C
inst✝⁵ : Category.{u_4, u_2} D
J : GrothendieckTopology C
inst✝⁴ : HasPullbacks D
inst✝³ : HasPushouts D
inst✝² : IsRegularEpiCategory D
h : ∀ {F G : Sheaf J D} (f : F ⟶ G) [Epi f], ∃ I p i, Epi p ∧ Mono i ∧ p ≫ i = f.hom
inst✝¹ : HasSheafify J D
inst✝ : Balanced (Sheaf J D)
F G : Sheaf J D
f : F ⟶ G
x✝ : Epi f
I : Cᵒᵖ ⥤ D
p : F.obj ⟶ I
i : I ⟶ G.obj
hp : Epi p
hi : Mono i
hpi : p ≫ i = f.hom
h₁ :
  (presheafToSheaf J D).map f.hom =
    (sheafificationAdjunction J D).counit.app F ≫ f ≫ inv ((sheafificationAdjunction J D).counit.app G)
h₂ :
  f =
    inv ((sheafificationAdjunction J D).counit.app F) ≫
      (presheafToSheaf J D).map f.hom ≫ (sheafificationAdjunction J D).counit.app G
this✝¹ : Epi ((presheafToSheaf J D).map f.hom)
this✝ : Epi ((presheafToSheaf J D).map i)
this : IsIso ((presheafToSheaf J D).map i)
⊢ EffectiveEpi ((presheafToSheaf J D).map (p ≫ i))

Tactic:
Functor.map_comp

Goal state after:
C : Type u_1
D : Type u_2
inst✝⁶ : Category.{u_3, u_1} C
inst✝⁵ : Category.{u_4, u_2} D
J : GrothendieckTopology C
inst✝⁴ : HasPullbacks D
inst✝³ : HasPushouts D
inst✝² : IsRegularEpiCategory D
h : ∀ {F G : Sheaf J D} (f : F ⟶ G) [Epi f], ∃ I p i, Epi p ∧ Mono i ∧ p ≫ i = f.hom
inst✝¹ : HasSheafify J D
inst✝ : Balanced (Sheaf J D)
F G : Sheaf J D
f : F ⟶ G
x✝ : Epi f
I : Cᵒᵖ ⥤ D
p : F.obj ⟶ I
i : I ⟶ G.obj
hp : Epi p
hi : Mono i
hpi : p ≫ i = f.hom
h₁ :
  (presheafToSheaf J D).map f.hom =
    (sheafificationAdjunction J D).counit.app F ≫ f ≫ inv ((sheafificationAdjunction J D).counit.app G)
h₂ :
  f =
    inv ((sheafificationAdjunction J D).counit.app F) ≫
      (presheafToSheaf J D).map f.hom ≫ (sheafificationAdjunction J D).counit.app G
this✝¹ : Epi ((presheafToSheaf J D).map f.hom)
this✝ : Epi ((presheafToSheaf J D).map i)
this : IsIso ((presheafToSheaf J D).map i)
⊢ EffectiveEpi ((presheafToSheaf J D).map p ≫ (presheafToSheaf J D).map i)
Module: Mathlib.CategoryTheory.Sites.Descent.DescentData

Goal state before:
pp: C : Type u
inst✝ : Category.{v, u} C
F : Pseudofunctor (LocallyDiscrete Cᵒᵖ) Cat
ι : Type t
S : C
X : ι → C
f : (i : ι) → X i ⟶ S
ι' : Type t'
X' : ι' → C
f' : (i' : ι') → X' i' ⟶ S
h : Sieve.ofArrows X f = Sieve.ofArrows X' f'
i' : ι'
⊢ (Sieve.ofArrows X f).arrows (f' i')

Tactic:
rw [h]; apply Sieve.ofArrows_mk

Goal state after: