Module: Mathlib.AlgebraicGeometry.ValuativeCriterion

Goal state before:
pp: case refine_1
X Y : Scheme
f : X ⟶ Y
R : Type u
commRing✝ : CommRing R
domain✝ : IsDomain R
valuationRing✝ : ValuationRing R
K : Type u
field✝ : Field K
algebra✝ : Algebra R K
isFractionRing✝ : IsFractionRing R K
i₁ : Spec (CommRingCat.of K) ⟶ X
i₂ : Spec (CommRingCat.of R) ⟶ Y
w : i₁ ≫ f = Spec.map (CommRingCat.ofHom (algebraMap R K)) ≫ i₂
this✝³ : IsDomain ↑(CommRingCat.of R)
this✝² : ValuationRing ↑(CommRingCat.of R)
this✝¹ : Field ↑(CommRingCat.of K) := field✝
H : topologically (@SpecializingMap) (pullback.fst i₂ f)
lft : Spec (CommRingCat.of K) ⟶ pullback i₂ f := pullback.lift (Spec.map (CommRingCat.ofHom (algebraMap R K))) i₁ ⋯
x : ↥(pullback i₂ f)
h₁ : flip (fun x1 x2 ↦ x1 ⤳ x2) x (lft (closedPoint ↑(CommRingCat.of K)))
h₂ : (pullback.fst i₂ f) x = closedPoint R
e : CommRingCat.of R ≅ (Spec (CommRingCat.of R)).presheaf.stalk ((pullback.fst i₂ f) x) :=
  (stalkClosedPointIso (CommRingCat.of R)).symm ≪≫ (Spec (CommRingCat.of R)).presheaf.stalkCongr ⋯
α : CommRingCat.of R ⟶ (pullback i₂ f).presheaf.stalk x := e.hom ≫ Scheme.Hom.stalkMap (pullback.fst i₂ f) x
this✝ : IsLocalHom (CommRingCat.Hom.hom e.hom)
this : IsLocalHom (CommRingCat.Hom.hom α)
β : (pullback i₂ f).presheaf.stalk x ⟶ CommRingCat.of K :=
  (pullback i₂ f).presheaf.stalkSpecializes h₁ ≫ Scheme.stalkClosedPointTo lft
hαβ : α ≫ β = CommRingCat.ofHom (algebraMap R K)
hbij : Function.Bijective ⇑((CommRingCat.Hom.hom β).rangeRestrict.comp (CommRingCat.Hom.hom α))
φ : (pullback i₂ f).presheaf.stalk x ⟶ CommRingCat.of R :=
  CommRingCat.ofHom
    ((RingEquiv.ofBijective ((CommRingCat.Hom.hom β).rangeRestrict.comp (CommRingCat.Hom.hom α))
              hbij).symm.toRingHom.comp
      (CommRingCat.Hom.hom β).rangeRestrict)
hαφ : α ≫ φ = 𝟙 (CommRingCat.of R)
hαφ' : Scheme.Hom.stalkMap (pullback.fst i₂ f) x ≫ φ = e.inv
hφβ : φ ≫ CommRingCat.ofHom (algebraMap R K) = β
⊢ Spec.map
        (CommRingCat.ofHom
          (algebraMap
            { R := R, commRing := commRing✝, domain := domain✝, valuationRing := valuationRing✝, K := K,
                field := field✝, algebra := algebra✝, isFractionRing := isFractionRing✝, i₁ := i₁, i₂ := i₂,
                commSq := ⋯ }.R
            { R := R, commRing := commRing✝, domain := domain✝, valuationRing := valuationRing✝, K := K,
                field := field✝, algebra := algebra✝, isFractionRing := isFractionRing✝, i₁ := i₁, i₂ := i₂,
                commSq := ⋯ }.K)) ≫
      Spec.map (Scheme.Hom.stalkMap (pullback.snd i₂ f) x ≫ φ) ≫ X.fromSpecStalk ((pullback.snd i₂ f) x) =
    { R := R, commRing := commRing✝, domain := domain✝, valuationRing := valuationRing✝, K := K, field := field✝,
        algebra := algebra✝, isFractionRing := isFractionRing✝, i₁ := i₁, i₂ := i₂, commSq := ⋯ }.i₁

Tactic:
simp only [← Spec.map_comp_assoc, Category.assoc, hφβ]

Goal state after:
case refine_1
X Y : Scheme
f : X ⟶ Y
R : Type u
commRing✝ : CommRing R
domain✝ : IsDomain R
valuationRing✝ : ValuationRing R
K : Type u
field✝ : Field K
algebra✝ : Algebra R K
isFractionRing✝ : IsFractionRing R K
i₁ : Spec (CommRingCat.of K) ⟶ X
i₂ : Spec (CommRingCat.of R) ⟶ Y
w : i₁ ≫ f = Spec.map (CommRingCat.ofHom (algebraMap R K)) ≫ i₂
this✝³ : IsDomain ↑(CommRingCat.of R)
this✝² : ValuationRing ↑(CommRingCat.of R)
this✝¹ : Field ↑(CommRingCat.of K) := field✝
H : topologically (@SpecializingMap) (pullback.fst i₂ f)
lft : Spec (CommRingCat.of K) ⟶ pullback i₂ f := pullback.lift (Spec.map (CommRingCat.ofHom (algebraMap R K))) i₁ ⋯
x : ↥(pullback i₂ f)
h₁ : flip (fun x1 x2 ↦ x1 ⤳ x2) x (lft (closedPoint ↑(CommRingCat.of K)))
h₂ : (pullback.fst i₂ f) x = closedPoint R
e : CommRingCat.of R ≅ (Spec (CommRingCat.of R)).presheaf.stalk ((pullback.fst i₂ f) x) :=
  (stalkClosedPointIso (CommRingCat.of R)).symm ≪≫ (Spec (CommRingCat.of R)).presheaf.stalkCongr ⋯
α : CommRingCat.of R ⟶ (pullback i₂ f).presheaf.stalk x := e.hom ≫ Scheme.Hom.stalkMap (pullback.fst i₂ f) x
this✝ : IsLocalHom (CommRingCat.Hom.hom e.hom)
this : IsLocalHom (CommRingCat.Hom.hom α)
β : (pullback i₂ f).presheaf.stalk x ⟶ CommRingCat.of K :=
  (pullback i₂ f).presheaf.stalkSpecializes h₁ ≫ Scheme.stalkClosedPointTo lft
hαβ : α ≫ β = CommRingCat.ofHom (algebraMap R K)
hbij : Function.Bijective ⇑((CommRingCat.Hom.hom β).rangeRestrict.comp (CommRingCat.Hom.hom α))
φ : (pullback i₂ f).presheaf.stalk x ⟶ CommRingCat.of R :=
  CommRingCat.ofHom
    ((RingEquiv.ofBijective ((CommRingCat.Hom.hom β).rangeRestrict.comp (CommRingCat.Hom.hom α))
              hbij).symm.toRingHom.comp
      (CommRingCat.Hom.hom β).rangeRestrict)
hαφ : α ≫ φ = 𝟙 (CommRingCat.of R)
hαφ' : Scheme.Hom.stalkMap (pullback.fst i₂ f) x ≫ φ = e.inv
hφβ : φ ≫ CommRingCat.ofHom (algebraMap R K) = β
⊢ Spec.map (Scheme.Hom.stalkMap (pullback.snd i₂ f) x ≫ β) ≫ X.fromSpecStalk ((pullback.snd i₂ f) x) = i₁