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

Goal state before:
pp: case h₂.uniq
J : Type v'
inst✝² : Category.{u', v'} J
C : Type u
inst✝¹ : Category.{v, u} C
D : Type u''
inst✝ : Category.{v'', u''} D
X Y : C
Z : Type u
f : Z ⟶ (Types.binaryCoproductCocone PUnit.{u + 1} PUnit.{u + 1}).pt
this :
  ∀ (x : (fun X ↦ X) Z),
    (ConcreteCategory.hom f) x = Sum.inl PUnit.unit ∨ (ConcreteCategory.hom f) x = Sum.inr PUnit.unit
eX : { p // (ConcreteCategory.hom f) p.1 = Sum.inl p.2 } ≃ { x // (ConcreteCategory.hom f) x = Sum.inl PUnit.unit } := ⋯
eY : { p // (ConcreteCategory.hom f) p.1 = Sum.inr p.2 } ≃ { x // (ConcreteCategory.hom f) x = Sum.inr PUnit.unit } := ⋯
⊢ ∀ (s : BinaryCofan (Types.PullbackObj f (↾Sum.inl)) (Types.PullbackObj f (↾Sum.inr))) (m : Z ⟶ s.pt),
    (↾fun p ↦ (↑p).1) ≫ m = s.inl →
      (↾fun p ↦ (↑p).1) ≫ m = s.inr →
        m =
          ↾fun x ↦
            if h : (ConcreteCategory.hom f) x = Sum.inl PUnit.unit then (ConcreteCategory.hom s.inl) (eX.symm ⟨x, h⟩)
            else (ConcreteCategory.hom s.inr) (eY.symm ⟨x, ⋯⟩)

Tactic:
intro s m e₁ e₂
      ext x
      simp only [TypeCat.Fun.toFun_apply, Types.binaryCoproductCocone_pt, pair_obj_left,
        Functor.const_obj_obj, pair_obj_right, ConcreteCategory.hom_ofHom, TypeCat.Fun.coe_mk]
      split_ifs
      · rw [← e₁]
        rfl
      · rw [← e₂]
        rfl

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

Goal state before:
pp: C : Type u
inst✝¹³ : Category.{v, u} C
J : GrothendieckTopology C
D : Type w
inst✝¹² : Category.{t, w} D
inst✝¹¹ : ∀ (P : Cᵒᵖ ⥤ D) (X : C) (S : J.Cover X), HasMultiequalizer (S.index P)
inst✝¹⁰ : ∀ (X : C), HasColimitsOfShape (J.Cover X)ᵒᵖ D
FD : D → D → Type u_1
CD : D → Type t
inst✝⁹ : (X Y : D) → FunLike (FD X Y) (CD X) (CD Y)
inst✝⁸ : ConcreteCategory D FD
inst✝⁷ : ∀ (X : C), PreservesColimitsOfShape (J.Cover X)ᵒᵖ (forget D)
inst✝⁶ : (forget D).ReflectsIsomorphisms
inst✝⁵ : ∀ {X : C} (S : J.Cover X), PreservesLimitsOfShape (WalkingMulticospan S.shape) (forget D)
K : Type w'
inst✝⁴ : SmallCategory K
inst✝³ : FinCategory K
inst✝² : HasLimitsOfShape K D
inst✝¹ : PreservesLimits (forget D)
inst✝ : ∀ (X : C), Small.{t, max u v} (J.Cover X)ᵒᵖ
⊢ PreservesLimitsOfShape K (plusPlusSheaf J D)

Tactic:
let e := (FinCategory.equivAsType K).symm.trans (AsSmall.equiv.{0, 0, t})
  have : HasLimitsOfShape (AsSmall.{t} (FinCategory.AsType K)) D :=
    Limits.hasLimitsOfShape_of_equivalence e
  have : FinCategory (AsSmall.{t} (FinCategory.AsType K)) := by
    constructor
    · change Fintype (ULift _)
      infer_instance
    · intro j j'
      change Fintype (ULift _)
      infer_instance
  refine @preservesLimitsOfShape_of_equiv _ _ _ _ _ _ _ _ e.symm _ (show _ from ?_)
  constructor; intro F; constructor; intro S hS; constructor
  apply isLimitOfReflects (sheafToPresheaf J D)
  have : ReflectsLimitsOfShape (AsSmall.{t} (FinCategory.AsType K)) (forget D) :=
    reflectsLimitsOfShape_of_reflectsIsomorphisms
  apply isLimitOfPreserves (J.sheafification D) hS

Goal state after:
Module: Mathlib.CategoryTheory.Localization.Bousfield

Goal state before:
pp: case mp
C : Type u_1
inst✝ : Category.{v_1, u_1} C
P : ObjectProperty C
X Y : C
f : X ⟶ Y
hf : P.isoClosure.isLocal f
Z : C
⊢ P Z → Function.Bijective fun g ↦ f ≫ g

Tactic:
hZ

Goal state after:
case mp
C : Type u_1
inst✝ : Category.{v_1, u_1} C
P : ObjectProperty C
X Y : C
f : X ⟶ Y
hf : P.isoClosure.isLocal f
Z : C
hZ : P Z
⊢ Function.Bijective fun g ↦ f ≫ g
Module: Mathlib.CategoryTheory.Adhesive.Basic

Goal state before:
pp: case i'_w.i'_w
J : Type v'
inst✝⁴ : Category.{u', v'} J
C : Type u
inst✝³ : Category.{v, u} C
W X Y Z✝ : C
f✝ : W ⟶ X
g✝ : W ⟶ Y
h : X ⟶ Z✝
i : Y ⟶ Z✝
inst✝² : Adhesive C
Z A B : C
a : A ⟶ Z
b : B ⟶ Z
inst✝¹ : Mono a
inst✝ : Mono b
K : C
f g : K ⟶ pushout (fst a b) (snd a b)
w : f ≫ pushout.desc a b ⋯ = g ≫ pushout.desc a b ⋯
u : A ⟶ pushout (fst a b) (snd a b) := inl (fst a b) (snd a b)
v : B ⟶ pushout (fst a b) (snd a b) := inr (fst a b) (snd a b)
this✝² : Mono u := mono_of_isPushout_of_mono_right (of_hasPushout (fst a b) (snd a b))
this✝¹ : Mono v := mono_of_isPushout_of_mono_left (of_hasPushout (fst a b) (snd a b))
sq_f_u : IsPullback (fst f u) (snd f u) f u := of_hasPullback f u
sq_f_v : IsPullback (fst f v) (snd f v) f v := of_hasPullback f v
sq_g_u : IsPullback (fst g u) (snd g u) g u := of_hasPullback g u
sq_g_v : IsPullback (fst g v) (snd g v) g v := of_hasPullback g v
l₁ : pullback f u ⟶ K := fst f u
f₁ : pullback f u ⟶ A := snd f u
l₂ : pullback f v ⟶ K := fst f v
f₂ : pullback f v ⟶ B := snd f v
m₁ : pullback g u ⟶ K := fst g u
g₁ : pullback g u ⟶ A := snd g u
m₂ : pullback g v ⟶ K := fst g v
g₂ : pullback g v ⟶ B := snd g v
w✝² : C
f' : w✝² ⟶ pullback f u
w✝¹ : w✝² ⟶ pullback f v
w✝ : w✝² ⟶ pullback a b
p₁ : IsPullback f' w✝ (snd f u) (fst a b)
left✝ : IsPullback w✝¹ w✝ (snd f v) (snd a b)
h₁ : IsPushout f' w✝¹ (fst f u) (fst f v)
this✝ : Mono f' := Eq.mpr (id (congrArg (fun _a ↦ Mono _a) (Eq.symm (isoPullback_hom_fst p₁)))) inferInstance
sq₂₁ : IsPullback (fst m₂ l₁) (snd m₂ l₁) m₂ l₁ := of_hasPullback m₂ l₁
sq₂₂ : IsPullback (fst m₂ l₂) (snd m₂ l₂) m₂ l₂ := of_hasPullback m₂ l₂
this : Mono (v ≫ pushout.desc a b ⋯) :=
  Eq.mpr (id (congrArg (fun _a ↦ Mono _a) (pushout.inr_desc a b pullback.condition))) inst✝
⊢ snd m₂ l₂ ≫ snd f v = fst m₂ l₂ ≫ snd g v

Tactic:
rw [← cancel_mono (v ≫ pushout.desc a b pullback.condition), Category.assoc,
          ← sq_f_v.w_assoc, w, ← pullback.condition_assoc, Category.assoc,
          ← sq_g_v.w_assoc]

Goal state after:
Module: Mathlib.CategoryTheory.Localization.Bousfield

Goal state before:
pp: C : Type u_1
D : Type u_2
inst✝³ : Category.{v_1, u_1} C
inst✝² : Category.{v_2, u_2} D
F : C ⥤ D
G : D ⥤ C
adj : G ⊣ F
inst✝¹ : G.Full
inst✝ : G.Faithful
⊢ F.IsLocalization (isColocal fun x ↦ x ∈ Set.range G.obj)

Tactic:
isColocal_eq_inverseImage_isomorphisms adj

Goal state after:
C : Type u_1
D : Type u_2
inst✝³ : Category.{v_1, u_1} C
inst✝² : Category.{v_2, u_2} D
F : C ⥤ D
G : D ⥤ C
adj : G ⊣ F
inst✝¹ : G.Full
inst✝ : G.Faithful
⊢ F.IsLocalization ((MorphismProperty.isomorphisms D).inverseImage F)
Module: Mathlib.CategoryTheory.Sites.Localization

Goal state before:
pp: C : Type u_1
inst✝¹ : Category.{v_1, u_1} C
J : GrothendieckTopology C
inst✝ : LocallySmall.{w, v_1, u_1} C
X : C
S : Sieve X
hS : S ∈ J X
Z : Cᵒᵖ ⥤ Type w
⊢ Presheaf.IsSheaf J Z → Function.Bijective fun g ↦ (shrinkFunctor.{w, v_1, u_1} S).ι ≫ g

Tactic:
hZ

Goal state after:
C : Type u_1
inst✝¹ : Category.{v_1, u_1} C
J : GrothendieckTopology C
inst✝ : LocallySmall.{w, v_1, u_1} C
X : C
S : Sieve X
hS : S ∈ J X
Z : Cᵒᵖ ⥤ Type w
hZ : Presheaf.IsSheaf J Z
⊢ Function.Bijective fun g ↦ (shrinkFunctor.{w, v_1, u_1} S).ι ≫ g
Module: Mathlib.CategoryTheory.Adhesive.Basic

Goal state before:
pp: C : Type u
inst✝⁹ : Category.{v, u} C
D : Type u''
inst✝⁸ : Category.{v'', u''} D
inst✝⁷ : HasPullbacks D
inst✝⁶ : Adhesive C
inst✝⁵ : HasPullbacks C
inst✝⁴ : HasPushouts C
H₂ : ∀ {X Y S : D} (f : S ⟶ X) (g : S ⟶ Y) [Mono f], HasPushout f g
Gl : C ⥤ D
Gr : D ⥤ C
adj : Gl ⊣ Gr
inst✝³ : Gr.Full
inst✝² : Gr.Faithful
inst✝¹ : PreservesLimitsOfShape WalkingCospan Gl
this✝¹ : PreservesColimitsOfSize.{?u.95, ?u.94, v, v'', u, u''} Gl
this✝ : PreservesLimitsOfSize.{v, v, v'', v, u'', u} Gr
W X Y Z : D
f : W ⟶ X
g : W ⟶ Y
h : X ⟶ Z
i : Y ⟶ Z
inst✝ : Mono f
H : IsPushout f g h i
this : IsVanKampenColimit (PushoutCocone.mk (pushout.inl (Gr.map f) (Gr.map g)) (pushout.inr (Gr.map f) (Gr.map g)) ⋯)
⊢ IsVanKampenColimit
    ((Cocone.precompose ((span f g).isoWhiskerLeft (asIso adj.counit) ≪≫ (span f g).rightUnitor).hom).obj
      (PushoutCocone.mk h i ⋯))

Tactic:
refine ((this.precompose_isIso (spanCompIso _ _ _).hom).map_reflective adj).of_iso
    (IsColimit.uniqueUpToIso ?_ ?_)

Goal state after:
case refine_1
C : Type u
inst✝⁹ : Category.{v, u} C
D : Type u''
inst✝⁸ : Category.{v'', u''} D
inst✝⁷ : HasPullbacks D
inst✝⁶ : Adhesive C
inst✝⁵ : HasPullbacks C
inst✝⁴ : HasPushouts C
H₂ : ∀ {X Y S : D} (f : S ⟶ X) (g : S ⟶ Y) [Mono f], HasPushout f g
Gl : C ⥤ D
Gr : D ⥤ C
adj : Gl ⊣ Gr
inst✝³ : Gr.Full
inst✝² : Gr.Faithful
inst✝¹ : PreservesLimitsOfShape WalkingCospan Gl
this✝¹ : PreservesColimitsOfSize.{?u.95, ?u.94, v, v'', u, u''} Gl
this✝ : PreservesLimitsOfSize.{v, v, v'', v, u'', u} Gr
W X Y Z : D
f : W ⟶ X
g : W ⟶ Y
h : X ⟶ Z
i : Y ⟶ Z
inst✝ : Mono f
H : IsPushout f g h i
this : IsVanKampenColimit (PushoutCocone.mk (pushout.inl (Gr.map f) (Gr.map g)) (pushout.inr (Gr.map f) (Gr.map g)) ⋯)
⊢ IsColimit
    (Gl.mapCocone
      ((Cocone.precompose (spanCompIso Gr f g).hom).obj
        (PushoutCocone.mk (pushout.inl (Gr.map f) (Gr.map g)) (pushout.inr (Gr.map f) (Gr.map g)) ⋯)))

case refine_2
C : Type u
inst✝⁹ : Category.{v, u} C
D : Type u''
inst✝⁸ : Category.{v'', u''} D
inst✝⁷ : HasPullbacks D
inst✝⁶ : Adhesive C
inst✝⁵ : HasPullbacks C
inst✝⁴ : HasPushouts C
H₂ : ∀ {X Y S : D} (f : S ⟶ X) (g : S ⟶ Y) [Mono f], HasPushout f g
Gl : C ⥤ D
Gr : D ⥤ C
adj : Gl ⊣ Gr
inst✝³ : Gr.Full
inst✝² : Gr.Faithful
inst✝¹ : PreservesLimitsOfShape WalkingCospan Gl
this✝¹ : PreservesColimitsOfSize.{?u.95, ?u.94, v, v'', u, u''} Gl
this✝ : PreservesLimitsOfSize.{v, v, v'', v, u'', u} Gr
W X Y Z : D
f : W ⟶ X
g : W ⟶ Y
h : X ⟶ Z
i : Y ⟶ Z
inst✝ : Mono f
H : IsPushout f g h i
this : IsVanKampenColimit (PushoutCocone.mk (pushout.inl (Gr.map f) (Gr.map g)) (pushout.inr (Gr.map f) (Gr.map g)) ⋯)
⊢ IsColimit
    ((Cocone.precompose ((span f g).isoWhiskerLeft (asIso adj.counit) ≪≫ (span f g).rightUnitor).hom).obj
      (PushoutCocone.mk h i ⋯))
Module: Mathlib.CategoryTheory.Sites.LocallyInjective

Goal state before:
pp: case mpr
C : Type u
inst✝⁴ : Category.{v, u} C
D : Type u'
inst✝³ : Category.{v', u'} D
FD : D → D → Type u_1
CD : D → Type w
inst✝² : (X Y : D) → FunLike (FD X Y) (CD X) (CD Y)
inst✝¹ : ConcreteCategory D FD
J : GrothendieckTopology C
F₁ F₂ F₃ : Cᵒᵖ ⥤ D
φ : F₁ ⟶ F₂
ψ : F₂ ⟶ F₃
φψ : F₁ ⟶ F₃
fac : φ ≫ ψ = φψ
inst✝ : IsLocallyInjective J ψ
a✝ : IsLocallyInjective J φ
⊢ IsLocallyInjective J φψ

Tactic:
rw [← fac]

Goal state after:
case mpr
C : Type u
inst✝⁴ : Category.{v, u} C
D : Type u'
inst✝³ : Category.{v', u'} D
FD : D → D → Type u_1
CD : D → Type w
inst✝² : (X Y : D) → FunLike (FD X Y) (CD X) (CD Y)
inst✝¹ : ConcreteCategory D FD
J : GrothendieckTopology C
F₁ F₂ F₃ : Cᵒᵖ ⥤ D
φ : F₁ ⟶ F₂
ψ : F₂ ⟶ F₃
φψ : F₁ ⟶ F₃
fac : φ ≫ ψ = φψ
inst✝ : IsLocallyInjective J ψ
a✝ : IsLocallyInjective J φ
⊢ IsLocallyInjective J (φ ≫ ψ)
Module: Mathlib.CategoryTheory.Sites.LocallyInjective

Goal state before:
pp: C : Type u
inst✝⁵ : Category.{v, u} C
D : Type u'
inst✝⁴ : Category.{v', u'} D
FD : D → D → Type u_1
CD : D → Type w
inst✝³ : (X Y : D) → FunLike (FD X Y) (CD X) (CD Y)
inst✝² : ConcreteCategory D FD
J : GrothendieckTopology C
F₁ F₂ : Sheaf J D
φ : F₁ ⟶ F₂
inst✝¹ : J.HasSheafCompose (forget D)
inst✝ : IsLocallyInjective φ
⊢ ∀ (X : Cᵒᵖ), Function.Injective ⇑(ConcreteCategory.hom (φ.hom.app X))

Tactic:
← isLocallyInjective_iff_injective

Goal state after:
C : Type u
inst✝⁵ : Category.{v, u} C
D : Type u'
inst✝⁴ : Category.{v', u'} D
FD : D → D → Type u_1
CD : D → Type w
inst✝³ : (X Y : D) → FunLike (FD X Y) (CD X) (CD Y)
inst✝² : ConcreteCategory D FD
J : GrothendieckTopology C
F₁ F₂ : Sheaf J D
φ : F₁ ⟶ F₂
inst✝¹ : J.HasSheafCompose (forget D)
inst✝ : IsLocallyInjective φ
⊢ IsLocallyInjective φ
Module: Mathlib.CategoryTheory.Sites.LocallySurjective

Goal state before:
pp: case mpr
C : Type u
inst✝⁴ : Category.{v, u} C
J : GrothendieckTopology C
A : Type u'
inst✝³ : Category.{v', u'} A
FA : A → A → Type u_1
CA : A → Type w'
inst✝² : (X Y : A) → FunLike (FA X Y) (CA X) (CA Y)
inst✝¹ : ConcreteCategory A FA
F₁ F₂ F₃ : Cᵒᵖ ⥤ A
f₁ : F₁ ⟶ F₂
f₂ : F₂ ⟶ F₃
f₃ : F₁ ⟶ F₃
fac : f₁ ≫ f₂ = f₃
inst✝ : IsLocallySurjective J f₁
a✝ : IsLocallySurjective J f₂
⊢ IsLocallySurjective J f₃

Tactic:
rw [← fac]

Goal state after:
case mpr
C : Type u
inst✝⁴ : Category.{v, u} C
J : GrothendieckTopology C
A : Type u'
inst✝³ : Category.{v', u'} A
FA : A → A → Type u_1
CA : A → Type w'
inst✝² : (X Y : A) → FunLike (FA X Y) (CA X) (CA Y)
inst✝¹ : ConcreteCategory A FA
F₁ F₂ F₃ : Cᵒᵖ ⥤ A
f₁ : F₁ ⟶ F₂
f₂ : F₂ ⟶ F₃
f₃ : F₁ ⟶ F₃
fac : f₁ ≫ f₂ = f₃
inst✝ : IsLocallySurjective J f₁
a✝ : IsLocallySurjective J f₂
⊢ IsLocallySurjective J (f₁ ≫ f₂)
Module: Mathlib.CategoryTheory.Sites.LocallySurjective

Goal state before:
pp: C : Type u
inst✝⁵ : Category.{v, u} C
J : GrothendieckTopology C
A : Type u'
inst✝⁴ : Category.{v', u'} A
FA : A → A → Type u_1
CA : A → Type w'
inst✝³ : (X Y : A) → FunLike (FA X Y) (CA X) (CA Y)
inst✝² : ConcreteCategory A FA
F₁ F₂ F₃ : Cᵒᵖ ⥤ A
f₁ : F₁ ⟶ F₂
f₂ : F₂ ⟶ F₃
inst✝¹ : IsLocallySurjective J (f₁ ≫ f₂)
inst✝ : IsLocallyInjective J f₂
X : C
x : ToType (F₂.obj (op X))
⊢ imageSieve f₁ x ∈ J X

Tactic:
let S := imageSieve (f₁ ≫ f₂) (f₂.app _ x)

Goal state after:
C : Type u
inst✝⁵ : Category.{v, u} C
J : GrothendieckTopology C
A : Type u'
inst✝⁴ : Category.{v', u'} A
FA : A → A → Type u_1
CA : A → Type w'
inst✝³ : (X Y : A) → FunLike (FA X Y) (CA X) (CA Y)
inst✝² : ConcreteCategory A FA
F₁ F₂ F₃ : Cᵒᵖ ⥤ A
f₁ : F₁ ⟶ F₂
f₂ : F₂ ⟶ F₃
inst✝¹ : IsLocallySurjective J (f₁ ≫ f₂)
inst✝ : IsLocallyInjective J f₂
X : C
x : ToType (F₂.obj (op X))
S : Sieve X := imageSieve (f₁ ≫ f₂) ((ConcreteCategory.hom (f₂.app (op X))) x)
⊢ imageSieve f₁ x ∈ J X
Module: Mathlib.CategoryTheory.Limits.VanKampen

Goal state before:
pp: case refine_2.refine_1.isFalse
C : Type u
inst✝² : Category.{v, u} C
inst✝¹ : HasInitial C
ι : Type u_3
X : ι → C
c : Cofan X
hc : IsVanKampenColimit c
i j✝ : ι
inst✝ : DecidableEq ι
t : Cofan fun k ↦ if k = i then X i else ⊥_ C
j : ι
h✝ : ¬j = i
⊢ (eqToHom ⋯ ≫ initial.to (X i)) ≫ eqToHom ⋯ ≫ t.inj i = t.inj j

Tactic:
· rw [Category.assoc, ← IsIso.eq_inv_comp]
        exact initialIsInitial.hom_ext _ _

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

Goal state before:
pp: case refine_2
C : Type u
inst✝ : Category.{v, u} C
ι : Type u_3
S B : C
X : ι → C
a : Cofan X
hau : IsUniversalColimit a
f : (i : ι) → X i ⟶ S
u : a.pt ⟶ S
v : B ⟶ S
s : (i : ι) → PullbackCone v (f i)
hs : (i : ι) → IsLimit (s i)
t : PullbackCone v u
ht : IsLimit t
d : Cofan fun i ↦ (s i).pt
e : d.pt ≅ t.pt
hu : ∀ (i : ι), a.inj i ≫ u = f i
he₁ : ∀ (i : ι), d.inj i ≫ e.hom ≫ t.fst = (s i).fst
he₂ : ∀ (i : ι), d.inj i ≫ e.hom ≫ t.snd = (s i).snd ≫ a.inj i
iso : d ≅ Cofan.mk t.pt fun i ↦ PullbackCone.IsLimit.lift ht (s i).fst ((s i).snd ≫ a.inj i) ⋯ := Cofan.ext e ⋯
j : Discrete ι
⊢ IsPullback (PullbackCone.IsLimit.lift ht (s j.as).fst ((s j.as).snd ≫ a.inj j.as) ⋯) (s j.as).snd t.snd (a.ι.app j)

Tactic:
← Cofan.inj

Goal state after:
case refine_2
C : Type u
inst✝ : Category.{v, u} C
ι : Type u_3
S B : C
X : ι → C
a : Cofan X
hau : IsUniversalColimit a
f : (i : ι) → X i ⟶ S
u : a.pt ⟶ S
v : B ⟶ S
s : (i : ι) → PullbackCone v (f i)
hs : (i : ι) → IsLimit (s i)
t : PullbackCone v u
ht : IsLimit t
d : Cofan fun i ↦ (s i).pt
e : d.pt ≅ t.pt
hu : ∀ (i : ι), a.inj i ≫ u = f i
he₁ : ∀ (i : ι), d.inj i ≫ e.hom ≫ t.fst = (s i).fst
he₂ : ∀ (i : ι), d.inj i ≫ e.hom ≫ t.snd = (s i).snd ≫ a.inj i
iso : d ≅ Cofan.mk t.pt fun i ↦ PullbackCone.IsLimit.lift ht (s i).fst ((s i).snd ≫ a.inj i) ⋯ := Cofan.ext e ⋯
j : Discrete ι
⊢ IsPullback (PullbackCone.IsLimit.lift ht (s j.as).fst ((s j.as).snd ≫ a.inj j.as) ⋯) (s j.as).snd t.snd (a.inj j.as)
Module: Mathlib.CategoryTheory.Limits.VanKampen

Goal state before:
pp: case refine_2
C : Type u
inst✝ : Category.{v, u} C
ι : Type u_3
S B : C
X : ι → C
a : Cofan X
hau : IsUniversalColimit a
f : (i : ι) → X i ⟶ S
u : a.pt ⟶ S
v : B ⟶ S
s : (i : ι) → PullbackCone (f i) v
hs : (i : ι) → IsLimit (s i)
t : PullbackCone u v
ht : IsLimit t
d : Cofan fun i ↦ (s i).pt
e : d.pt ≅ t.pt
hu : ∀ (i : ι), a.inj i ≫ u = f i
he₁ : ∀ (i : ι), d.inj i ≫ e.hom ≫ t.fst = (s i).fst ≫ a.inj i
he₂ : ∀ (i : ι), d.inj i ≫ e.hom ≫ t.snd = (s i).snd
iso : d ≅ Cofan.mk t.pt fun i ↦ PullbackCone.IsLimit.lift ht ((s i).fst ≫ a.inj i) (s i).snd ⋯ := Cofan.ext e ⋯
j : Discrete ι
⊢ IsPullback (PullbackCone.IsLimit.lift ht ((s j.as).fst ≫ a.inj j.as) (s j.as).snd ⋯) (s j.as).fst t.fst (a.ι.app j)

Tactic:
← Cofan.inj

Goal state after:
case refine_2
C : Type u
inst✝ : Category.{v, u} C
ι : Type u_3
S B : C
X : ι → C
a : Cofan X
hau : IsUniversalColimit a
f : (i : ι) → X i ⟶ S
u : a.pt ⟶ S
v : B ⟶ S
s : (i : ι) → PullbackCone (f i) v
hs : (i : ι) → IsLimit (s i)
t : PullbackCone u v
ht : IsLimit t
d : Cofan fun i ↦ (s i).pt
e : d.pt ≅ t.pt
hu : ∀ (i : ι), a.inj i ≫ u = f i
he₁ : ∀ (i : ι), d.inj i ≫ e.hom ≫ t.fst = (s i).fst ≫ a.inj i
he₂ : ∀ (i : ι), d.inj i ≫ e.hom ≫ t.snd = (s i).snd
iso : d ≅ Cofan.mk t.pt fun i ↦ PullbackCone.IsLimit.lift ht ((s i).fst ≫ a.inj i) (s i).snd ⋯ := Cofan.ext e ⋯
j : Discrete ι
⊢ IsPullback (PullbackCone.IsLimit.lift ht ((s j.as).fst ≫ a.inj j.as) (s j.as).snd ⋯) (s j.as).fst t.fst (a.inj j.as)
Module: Mathlib.CategoryTheory.Abelian.Projective.Dimension

Goal state before:
pp: C : Type u
inst✝³ : Category.{v, u} C
inst✝² : Abelian C
inst✝¹ : HasExt C
inst✝ : EnoughInjectives C
X : C
n : ℕ
hX : ∀ (Y : C), Subsingleton (Ext X Y n)
d : ℕ
Y : C
e : Ext X Y d
k : ℕ
⊢ d = n + k → e = 0

Tactic:
hd

Goal state after:
C : Type u
inst✝³ : Category.{v, u} C
inst✝² : Abelian C
inst✝¹ : HasExt C
inst✝ : EnoughInjectives C
X : C
n : ℕ
hX : ∀ (Y : C), Subsingleton (Ext X Y n)
d : ℕ
Y : C
e : Ext X Y d
k : ℕ
hd : d = n + k
⊢ e = 0
Module: Mathlib.CategoryTheory.Abelian.Projective.Dimension

Goal state before:
pp: C : Type u
inst✝¹ : Category.{v, u} C
inst✝ : Abelian C
X Y : C
h : Retract X Y
n : WithBot ℕ∞
hn : n ∈ {n | ∀ (i : ℕ), n < ↑i → HasProjectiveDimensionLT Y i}
⊢ n ∈ insert ⊤ {n | ∀ (i : ℕ), n < ↑i → HasProjectiveDimensionLT X i}

Tactic:
simp only [Set.mem_ofPred_eq, not_top_lt, IsEmpty.forall_iff, implies_true,
      Set.insert_eq_of_mem] at hn ⊢
    intro i hi
    have := hn i hi
    exact h.hasProjectiveDimensionLT i

Goal state after:
Module: Mathlib.CategoryTheory.Abelian.Projective.Dimension

Goal state before:
pp: case refine_2
C : Type u
inst✝¹ : Category.{v, u} C
inst✝ : Abelian C
X : C
n : ℕ
h : HasProjectiveDimensionLT X n
⊢ ∃ a ∈ {n | ∀ (i : ℕ), n < ↑i → HasProjectiveDimensionLT X i}, a < ↑n

Tactic:
obtain _ | n := n
    · exact ⟨⊥, fun _ _ ↦ hasProjectiveDimensionLT_of_ge _ 0 _ (by simp), by decide⟩
    · exact ⟨n, fun i hi ↦ hasProjectiveDimensionLT_of_ge _ (n + 1) _ (by simpa using hi),
        by simp [ENat.WithBot.lt_add_one_iff]⟩

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

Goal state before:
pp: C : Type u
inst✝ : Category.{v, u} C
J₁ : GrothendieckTopology C
X Y : C
f : Y ⟶ X
S : Sieve X
hS : J₁.IsClosed S
Z : C
g : Z ⟶ Y
hg : J₁.Covers (Sieve.pullback f S) g
⊢ J₁.Covers S (g ≫ f)

Tactic:
J₁.covers_iff,

Goal state after:
C : Type u
inst✝ : Category.{v, u} C
J₁ : GrothendieckTopology C
X Y : C
f : Y ⟶ X
S : Sieve X
hS : J₁.IsClosed S
Z : C
g : Z ⟶ Y
hg : J₁.Covers (Sieve.pullback f S) g
⊢ Sieve.pullback (g ≫ f) S ∈ J₁ Z
Module: Mathlib.CategoryTheory.Sites.Hypercover.Zero

Goal state before:
pp: C : Type u
inst✝ : Category.{v, u} C
S : C
⊢ (empty S).presieve₀ = ⊥

Tactic:
by
  grind

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

Goal state before:
pp: C : Type u
inst✝ : Category.{v, u} C
J₁ J₂ : GrothendieckTopology C
c : (X : C) → ClosureOperator (Sieve X)
hc : ∀ ⦃X Y : C⦄ (f : Y ⟶ X) (S : Sieve X), (c Y) (Sieve.pullback f S) = Sieve.pullback f ((c X) S)
X : C
S : Sieve X
hS : (c X) S = ⊤
R : Sieve X
hR : ∀ ⦃Y : C⦄ ⦃f : Y ⟶ X⦄, S.arrows f → Sieve.pullback f R ∈ {S | (c Y) S = ⊤}
⊢ R ∈ {S | (c X) S = ⊤}

Tactic:
rw [Set.mem_ofPred_eq, ← (c X).idempotent, eq_top_iff, ← hS]

Goal state after:
C : Type u
inst✝ : Category.{v, u} C
J₁ J₂ : GrothendieckTopology C
c : (X : C) → ClosureOperator (Sieve X)
hc : ∀ ⦃X Y : C⦄ (f : Y ⟶ X) (S : Sieve X), (c Y) (Sieve.pullback f S) = Sieve.pullback f ((c X) S)
X : C
S : Sieve X
hS : (c X) S = ⊤
R : Sieve X
hR : ∀ ⦃Y : C⦄ ⦃f : Y ⟶ X⦄, S.arrows f → Sieve.pullback f R ∈ {S | (c Y) S = ⊤}
⊢ (c X) S ≤ (c X) ((c X) R)
Module: Mathlib.CategoryTheory.Sites.PrecoverageToGrothendieck

Goal state before:
pp: case refine_1.of
C : Type u_2
inst✝ : Category.{u_1, u_2} C
J : Precoverage C
K : GrothendieckTopology C
hK : K ∈ {K | ∀ ⦃X : C⦄, ∀ S ∈ J.coverings X, Sieve.generate S ∈ K X}
i✝ : C
a✝ : Sieve i✝
X✝ : C
S✝ : Presieve X✝
hS : S✝ ∈ J.coverings X✝
⊢ Sieve.generate S✝ ∈ K X✝

Tactic:
exact hK _ hS

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

Goal state before:
pp: C : Type u_2
inst✝ : Category.{v_1, u_2} C
K : Coverage C
P : Cᵒᵖ ⥤ Type u_1
⊢ IsSheaf K.toGrothendieck P ↔ ∀ {X : C}, ∀ R ∈ K.coverings X, IsSheafFor P R

Tactic:
← toGrothendieck_toPrecoverage,

Goal state after:
C : Type u_2
inst✝ : Category.{v_1, u_2} C
K : Coverage C
P : Cᵒᵖ ⥤ Type u_1
⊢ IsSheaf K.toGrothendieck P ↔ ∀ {X : C}, ∀ R ∈ K.coverings X, IsSheafFor P R
Module: Mathlib.CategoryTheory.Sites.Coverage

Goal state before:
pp: C : Type u_2
inst✝³ : Category.{v_1, u_2} C
J : Precoverage C
inst✝² : J.IsStableUnderBaseChange
inst✝¹ : J.HasPullbacks
inst✝ : J.Small
P : Cᵒᵖ ⥤ Type u_1
h : ∀ ⦃X : C⦄ (E : J.ZeroHypercover X), Presieve.IsSheafFor P E.presieve₀
X : C
E₀ : PreZeroHypercover X
hR : E₀.presieve₀ ∈ J.coverings X
⊢ Presieve.IsSheafFor P E₀.presieve₀

Tactic:
rw [Presieve.isSheafFor_iff_generate]

Goal state after:
C : Type u_2
inst✝³ : Category.{v_1, u_2} C
J : Precoverage C
inst✝² : J.IsStableUnderBaseChange
inst✝¹ : J.HasPullbacks
inst✝ : J.Small
P : Cᵒᵖ ⥤ Type u_1
h : ∀ ⦃X : C⦄ (E : J.ZeroHypercover X), Presieve.IsSheafFor P E.presieve₀
X : C
E₀ : PreZeroHypercover X
hR : E₀.presieve₀ ∈ J.coverings X
⊢ Presieve.IsSheafFor P (Sieve.generate E₀.presieve₀).arrows
Module: Mathlib.CategoryTheory.Sites.PrecoverageToGrothendieck

Goal state before:
pp: C : Type u_4
inst✝³ : Category.{u_3, u_4} C
D : Type u_1
inst✝² : Category.{v_1, u_1} D
F : C ⥤ D
P : Dᵒᵖ ⥤ Type u_2
X : C
R : Presieve X
inst✝¹ : R.HasPairwisePullbacks
inst✝ : F.PreservesPairwisePullbacks R
⊢ IsSheafFor (F.op ⋙ P) R ↔ IsSheafFor P (map F R)

Tactic:
have : (R.map F).HasPairwisePullbacks := .map_of_preservesPairwisePullbacks _ _
  obtain ⟨ι, Y, f, rfl⟩ := R.exists_eq_ofArrows
  rw [map_ofArrows] at this ⊢
  simp_rw [Presieve.isSheafFor_arrows_iff_pullbacks]
  dsimp [Arrows.PullbackCompatible]
  congr! with x
  rw [forall₂_congr]
  intro i j
  have : PreservesLimit (cospan (f i) (f j)) F :=
    F.preservesLimit_cospan_of_mem_presieve (ofArrows _ f) ⟨i⟩ ⟨j⟩
  have : HasPullback (F.map (f i)) (F.map (f j)) := hasPullback_of_preservesPullback _ _ _
  rw [← pullbackComparison_comp_fst, op_comp, Functor.map_comp,
    ← pullbackComparison_comp_snd, op_comp, Functor.map_comp]
  have : Function.Bijective (P.map (pullbackComparison F (f i) (f j)).op) := by
    rw [← isIso_iff_bijective]
    infer_instance
  exact this.1.eq_iff

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

Goal state before:
pp: C : Type u
inst✝¹ : Category.{v, u} C
P : Cᵒᵖ ⥤ Type w
X✝ : C
J✝ J : GrothendieckTopology C
inst✝ : J.Subcanonical
X : C
⊢ Presheaf.IsSheaf J (CategoryTheory.yoneda.obj X)

Tactic:
by
    rw [isSheaf_iff_isSheaf_of_type]
    apply Subcanonical.isSheaf_of_isRepresentable

Goal state after:
Module: Mathlib.CategoryTheory.Sites.Hypercover.One

Goal state before:
pp: C : Type u
inst✝ : Category.{v, u} C
S : C
E : PreOneHypercover S
F : PreOneHypercover S
f g : E.Hom F
hs₀ : f.s₀ = g.s₀
hh₀ : ∀ (i : E.I₀), f.h₀ i = g.h₀ i ≫ eqToHom ⋯
hs₁ : ∀ (i j : E.I₀) (k : E.I₁ i j), f.s₁ k = (congrIndexOneOfEq ⋯ ⋯) (g.s₁ k)
hh₁ : ∀ (i j : E.I₀) (k : E.I₁ i j), f.h₁ k = g.h₁ k ≫ (congrIndexOneOfEqIso ⋯ ⋯ (g.s₁ k)).inv ≫ eqToHom ⋯
⊢ f = g

Tactic:
by
  obtain ⟨toHomf, fs₁, fh₁⟩ := f
  obtain ⟨toHomg, gs₁, gh₁⟩ := g
  obtain rfl : toHomf = toHomg := PreZeroHypercover.Hom.ext' hs₀ hh₀
  obtain rfl : @fs₁ = @gs₁ := by
    ext i j k
    simpa using hs₁ i j k
  simp_all only [eqToHom_refl, Category.comp_id, implies_true, congrIndexOneOfEqIso_refl,
    Iso.refl_inv, mk.injEq, heq_eq_eq, true_and]
  ext i j k
  rw [hh₁ i j k]
  exact Category.comp_id _

Goal state after: