Theorem: CategoryTheory.GrothendieckTopology.Subpresheaf.eq_sheafify
File: Mathlib/CategoryTheory/Sites/Subsheaf.lean

Proof steps:
state_before: C : Type u
inst✝ : Category.{v, u} C
J : GrothendieckTopology C
F F' F'' : Cᵒᵖ ⥤ Type w
G G' : Subpresheaf F
h : Presieve.IsSheaf J F
hG : Presieve.IsSheaf J G.toPresheaf
⊢ G = sheafify J G
state_after: C : Type u
inst✝ : Category.{v, u} C
J : GrothendieckTopology C
F F' F'' : Cᵒᵖ ⥤ Type w
G G' : Subpresheaf F
h : Presieve.IsSheaf J F
hG : Presieve.IsSheaf J G.toPresheaf
⊢ sheafify J G ≤ G
tactic: apply (G.le_sheafify J).antisymm
state_before: C : Type u
inst✝ : Category.{v, u} C
J : GrothendieckTopology C
F F' F'' : Cᵒᵖ ⥤ Type w
G G' : Subpresheaf F
h : Presieve.IsSheaf J F
hG : Presieve.IsSheaf J G.toPresheaf
⊢ sheafify J G ≤ G
state_after: C : Type u
inst✝ : Category.{v, u} C
J : GrothendieckTopology C
F F' F'' : Cᵒᵖ ⥤ Type w
G G' : Subpresheaf F
h : Presieve.IsSheaf J F
hG : Presieve.IsSheaf J G.toPresheaf
U : Cᵒᵖ
s : F.obj U
hs : s ∈ (sheafify J G).obj U
⊢ s ∈ G.obj U
tactic: intro U s hs
state_before: C : Type u
inst✝ : Category.{v, u} C
J : GrothendieckTopology C
F F' F'' : Cᵒᵖ ⥤ Type w
G G' : Subpresheaf F
h : Presieve.IsSheaf J F
hG : Presieve.IsSheaf J G.toPresheaf
U : Cᵒᵖ
s : F.obj U
hs : s ∈ (sheafify J G).obj U
⊢ s ∈ G.obj U
state_after: C : Type u
inst✝ : Category.{v, u} C
J : GrothendieckTopology C
F F' F'' : Cᵒᵖ ⥤ Type w
G G' : Subpresheaf F
h : Presieve.IsSheaf J F
hG : Presieve.IsSheaf J G.toPresheaf
U : Cᵒᵖ
s : F.obj U
hs : s ∈ (sheafify J G).obj U
⊢ ↑(⋯.amalgamate (G.familyOfElementsOfSection s) ⋯) = s
tactic: suffices ((hG _ hs).amalgamate _ (G.family_of_elements_compatible s)).1 = s by
    rw [← this]
    exact ((hG _ hs).amalgamate _ (G.family_of_elements_compatible s)).2
state_before: C : Type u
inst✝ : Category.{v, u} C
J : GrothendieckTopology C
F F' F'' : Cᵒᵖ ⥤ Type w
G G' : Subpresheaf F
h : Presieve.IsSheaf J F
hG : Presieve.IsSheaf J G.toPresheaf
U : Cᵒᵖ
s : F.obj U
hs : s ∈ (sheafify J G).obj U
⊢ ↑(⋯.amalgamate (G.familyOfElementsOfSection s) ⋯) = s
state_after: C : Type u
inst✝ : Category.{v, u} C
J : GrothendieckTopology C
F F' F'' : Cᵒᵖ ⥤ Type w
G G' : Subpresheaf F
h : Presieve.IsSheaf J F
hG : Presieve.IsSheaf J G.toPresheaf
U : Cᵒᵖ
s : F.obj U
hs : s ∈ (sheafify J G).obj U
⊢ ∀ ⦃Y : C⦄ ⦃f : Y ⟶ unop U⦄,
    (G.sieveOfSection s).arrows f → F.map f.op ↑(⋯.amalgamate (G.familyOfElementsOfSection s) ⋯) = F.map f.op s
tactic: apply (h _ hs).isSeparatedFor.ext
state_before: C : Type u
inst✝ : Category.{v, u} C
J : GrothendieckTopology C
F F' F'' : Cᵒᵖ ⥤ Type w
G G' : Subpresheaf F
h : Presieve.IsSheaf J F
hG : Presieve.IsSheaf J G.toPresheaf
U : Cᵒᵖ
s : F.obj U
hs : s ∈ (sheafify J G).obj U
⊢ ∀ ⦃Y : C⦄ ⦃f : Y ⟶ unop U⦄,
    (G.sieveOfSection s).arrows f → F.map f.op ↑(⋯.amalgamate (G.familyOfElementsOfSection s) ⋯) = F.map f.op s
state_after: C : Type u
inst✝ : Category.{v, u} C
J : GrothendieckTopology C
F F' F'' : Cᵒᵖ ⥤ Type w
G G' : Subpresheaf F
h : Presieve.IsSheaf J F
hG : Presieve.IsSheaf J G.toPresheaf
U : Cᵒᵖ
s : F.obj U
hs : s ∈ (sheafify J G).obj U
V : C
i : V ⟶ unop U
hi : (G.sieveOfSection s).arrows i
⊢ F.map i.op ↑(⋯.amalgamate (G.familyOfElementsOfSection s) ⋯) = F.map i.op s
tactic: intro V i hi
state_before: C : Type u
inst✝ : Category.{v, u} C
J : GrothendieckTopology C
F F' F'' : Cᵒᵖ ⥤ Type w
G G' : Subpresheaf F
h : Presieve.IsSheaf J F
hG : Presieve.IsSheaf J G.toPresheaf
U : Cᵒᵖ
s : F.obj U
hs : s ∈ (sheafify J G).obj U
V : C
i : V ⟶ unop U
hi : (G.sieveOfSection s).arrows i
⊢ F.map i.op ↑(⋯.amalgamate (G.familyOfElementsOfSection s) ⋯) = F.map i.op s
state_after: no goals
tactic: exact (congr_arg Subtype.val ((hG _ hs).valid_glue (G.family_of_elements_compatible s) _ hi) : _)