-- Mathlib/AlgebraicGeometry/ProjectiveSpectrum/Scheme.lean
lemma awayToΓ_ΓToStalk (f) (x) :
    awayToΓ 𝒜 f ≫ (Proj| pbo f).presheaf.Γgerm x =
      CommRingCat.ofHom (HomogeneousLocalization.mapId 𝒜 (Submonoid.powers_le.mpr x.2)) ≫
      (Proj.stalkIso' 𝒜 x.1).toCommRingCatIso.inv ≫
      ((Proj.toLocallyRingedSpace 𝒜).restrictStalkIso (Opens.isOpenEmbedding _) x).inv

Proof state:
R : Type u_1
A : Type u_2
inst✝³ : CommRing R
inst✝² : CommRing A
inst✝¹ : Algebra R A
𝒜 : ℕ → Submodule R A
inst✝ : GradedAlgebra 𝒜
f : A
x : ↑↑(Proj.restrict ⋯).toPresheafedSpace
⊢ awayToSection 𝒜 f ≫
      (structureSheaf 𝒜).val.map (homOfLE ⋯).op ≫
        Proj.presheaf.germ (⋯.functor.obj ⊤) ((ConcreteCategory.hom (pbo f).inclusion') x) ⋯ =
    CommRingCat.ofHom (HomogeneousLocalization.mapId 𝒜 ⋯) ≫ («Proj».stalkIso' 𝒜 ↑x).toCommRingCatIso.inv

Tactic:
simp only [Proj.toLocallyRingedSpace, Proj.toSheafedSpace]

Result:
R : Type u_1
A : Type u_2
inst✝³ : CommRing R
inst✝² : CommRing A
inst✝¹ : Algebra R A
𝒜 : ℕ → Submodule R A
inst✝ : GradedAlgebra 𝒜
f : A
x : ↑↑(Proj.restrict ⋯).toPresheafedSpace
⊢ awayToSection 𝒜 f ≫
      (structureSheaf 𝒜).val.map (homOfLE ⋯).op ≫
        Presheaf.germ (structureSheaf 𝒜).val (⋯.functor.obj ⊤) ((ConcreteCategory.hom (pbo f).inclusion') x) ⋯ =
    CommRingCat.ofHom (HomogeneousLocalization.mapId 𝒜 ⋯) ≫ («Proj».stalkIso' 𝒜 ↑x).toCommRingCatIso.inv

Proof state:
R : Type u_1
A : Type u_2
inst✝³ : CommRing R
inst✝² : CommRing A
inst✝¹ : Algebra R A
𝒜 : ℕ → Submodule R A
inst✝ : GradedAlgebra 𝒜
f : A
x : ↑↑(Proj.restrict ⋯).toPresheafedSpace
⊢ awayToΓ 𝒜 f ≫ (Proj.restrict ⋯).presheaf.Γgerm x =
    CommRingCat.ofHom (HomogeneousLocalization.mapId 𝒜 ⋯) ≫
      («Proj».stalkIso' 𝒜 ↑x).toCommRingCatIso.inv ≫ (Proj.restrictStalkIso ⋯ x).inv

Tactic:
rw [awayToΓ, Category.assoc, ← Category.assoc _ (Iso.inv _),
  Iso.eq_comp_inv, Category.assoc, Category.assoc, Presheaf.Γgerm]

Result:
R : Type u_1
A : Type u_2
inst✝³ : CommRing R
inst✝² : CommRing A
inst✝¹ : Algebra R A
𝒜 : ℕ → Submodule R A
inst✝ : GradedAlgebra 𝒜
f : A
x : ↑↑(Proj.restrict ⋯).toPresheafedSpace
⊢ awayToSection 𝒜 f ≫
      (structureSheaf 𝒜).val.map (homOfLE ⋯).op ≫
        (Proj.restrict ⋯).presheaf.germ ⊤ x True.intro ≫ (Proj.restrictStalkIso ⋯ x).hom =
    CommRingCat.ofHom (HomogeneousLocalization.mapId 𝒜 ⋯) ≫ («Proj».stalkIso' 𝒜 ↑x).toCommRingCatIso.inv

Proof state:
R : Type u_1
A : Type u_2
inst✝³ : CommRing R
inst✝² : CommRing A
inst✝¹ : Algebra R A
𝒜 : ℕ → Submodule R A
inst✝ : GradedAlgebra 𝒜
f : A
x : ↑↑(Proj.restrict ⋯).toPresheafedSpace
⊢ awayToSection 𝒜 f ≫
      (structureSheaf 𝒜).val.map (homOfLE ⋯).op ≫
        Presheaf.germ (structureSheaf 𝒜).val (⋯.functor.obj ⊤) ((ConcreteCategory.hom (pbo f).inclusion') x) ⋯ =
    CommRingCat.ofHom (HomogeneousLocalization.mapId 𝒜 ⋯) ≫ («Proj».stalkIso' 𝒜 ↑x).toCommRingCatIso.inv

Tactic:
rw [Presheaf.germ_res, awayToSection_germ]

Result:
R : Type u_1
A : Type u_2
inst✝³ : CommRing R
inst✝² : CommRing A
inst✝¹ : Algebra R A
𝒜 : ℕ → Submodule R A
inst✝ : GradedAlgebra 𝒜
f : A
x : ↑↑(Proj.restrict ⋯).toPresheafedSpace
⊢ CommRingCat.ofHom (HomogeneousLocalization.mapId 𝒜 ⋯) ≫
      («Proj».stalkIso' 𝒜 ((ConcreteCategory.hom (pbo f).inclusion') x)).toCommRingCatIso.inv =
    CommRingCat.ofHom (HomogeneousLocalization.mapId 𝒜 ⋯) ≫ («Proj».stalkIso' 𝒜 ↑x).toCommRingCatIso.inv

Proof state:
R : Type u_1
A : Type u_2
inst✝³ : CommRing R
inst✝² : CommRing A
inst✝¹ : Algebra R A
𝒜 : ℕ → Submodule R A
inst✝ : GradedAlgebra 𝒜
f : A
x : ↑↑(Proj.restrict ⋯).toPresheafedSpace
⊢ awayToSection 𝒜 f ≫
      (structureSheaf 𝒜).val.map (homOfLE ⋯).op ≫
        (Proj.restrict ⋯).presheaf.germ ⊤ x True.intro ≫ (Proj.restrictStalkIso ⋯ x).hom =
    CommRingCat.ofHom (HomogeneousLocalization.mapId 𝒜 ⋯) ≫ («Proj».stalkIso' 𝒜 ↑x).toCommRingCatIso.inv

Tactic:
rw [LocallyRingedSpace.restrictStalkIso_hom_eq_germ]

Result:
R : Type u_1
A : Type u_2
inst✝³ : CommRing R
inst✝² : CommRing A
inst✝¹ : Algebra R A
𝒜 : ℕ → Submodule R A
inst✝ : GradedAlgebra 𝒜
f : A
x : ↑↑(Proj.restrict ⋯).toPresheafedSpace
⊢ awayToSection 𝒜 f ≫
      (structureSheaf 𝒜).val.map (homOfLE ⋯).op ≫
        Proj.presheaf.germ (⋯.functor.obj ⊤) ((ConcreteCategory.hom (pbo f).inclusion') x) ⋯ =
    CommRingCat.ofHom (HomogeneousLocalization.mapId 𝒜 ⋯) ≫ («Proj».stalkIso' 𝒜 ↑x).toCommRingCatIso.inv

Proof state:
R : Type u_1
A : Type u_2
inst✝³ : CommRing R
inst✝² : CommRing A
inst✝¹ : Algebra R A
𝒜 : ℕ → Submodule R A
inst✝ : GradedAlgebra 𝒜
f : A
x : ↑↑(Proj.restrict ⋯).toPresheafedSpace
⊢ CommRingCat.ofHom (HomogeneousLocalization.mapId 𝒜 ⋯) ≫
      («Proj».stalkIso' 𝒜 ((ConcreteCategory.hom (pbo f).inclusion') x)).toCommRingCatIso.inv =
    CommRingCat.ofHom (HomogeneousLocalization.mapId 𝒜 ⋯) ≫ («Proj».stalkIso' 𝒜 ↑x).toCommRingCatIso.inv

Tactic:
rfl

Result:
no goals