Module: Mathlib.AlgebraicGeometry.Morphisms.FlatRank

Goal state before:
pp: R S : CommRingCat
f : R ⟶ S
hf₁✝ : IsFinite (Spec.map f)
hf₂✝ : Flat (Spec.map f)
hf₁ : (CommRingCat.Hom.hom (appTop (Spec.map f))).Finite
hf₂ : (CommRingCat.Hom.hom (appTop (Spec.map f))).Flat
x✝ : ↥(Spec R)
this : f = (ΓSpecIso R).inv ≫ appTop (Spec.map f) ≫ (ΓSpecIso S).hom
⊢ (CommRingCat.Hom.hom (appTop (Spec.map f))).finrank ((Spec R).isoSpec.hom x✝) =
    ((CommRingCat.Hom.hom (ΓSpecIso S).hom).comp (CommRingCat.Hom.hom (appTop (Spec.map f)))).finrank ?x

pp: case h1
R S : CommRingCat
f : R ⟶ S
hf₁✝ : IsFinite (Spec.map f)
hf₂✝ : Flat (Spec.map f)
hf₁ : (CommRingCat.Hom.hom (appTop (Spec.map f))).Finite
hf₂ : (CommRingCat.Hom.hom (appTop (Spec.map f))).Flat
x✝ : ↥(Spec R)
this : f = (ΓSpecIso R).inv ≫ appTop (Spec.map f) ≫ (ΓSpecIso S).hom
⊢ ((CommRingCat.Hom.hom (ΓSpecIso S).hom).comp (CommRingCat.Hom.hom (appTop (Spec.map f)))).Finite

pp: case h2
R S : CommRingCat
f : R ⟶ S
hf₁✝ : IsFinite (Spec.map f)
hf₂✝ : Flat (Spec.map f)
hf₁ : (CommRingCat.Hom.hom (appTop (Spec.map f))).Finite
hf₂ : (CommRingCat.Hom.hom (appTop (Spec.map f))).Flat
x✝ : ↥(Spec R)
this : f = (ΓSpecIso R).inv ≫ appTop (Spec.map f) ≫ (ΓSpecIso S).hom
⊢ ((CommRingCat.Hom.hom (ΓSpecIso S).hom).comp (CommRingCat.Hom.hom (appTop (Spec.map f)))).Flat

pp: case x
R S : CommRingCat
f : R ⟶ S
hf₁✝ : IsFinite (Spec.map f)
hf₂✝ : Flat (Spec.map f)
hf₁ : (CommRingCat.Hom.hom (appTop (Spec.map f))).Finite
hf₂ : (CommRingCat.Hom.hom (appTop (Spec.map f))).Flat
x✝ : ↥(Spec R)
this : f = (ΓSpecIso R).inv ≫ appTop (Spec.map f) ≫ (ΓSpecIso S).hom
⊢ PrimeSpectrum ↑Γ(Spec R, ⊤)

pp: case hy
R S : CommRingCat
f : R ⟶ S
hf₁✝ : IsFinite (Spec.map f)
hf₂✝ : Flat (Spec.map f)
hf₁ : (CommRingCat.Hom.hom (appTop (Spec.map f))).Finite
hf₂ : (CommRingCat.Hom.hom (appTop (Spec.map f))).Flat
x✝ : ↥(Spec R)
this : f = (ΓSpecIso R).inv ≫ appTop (Spec.map f) ≫ (ΓSpecIso S).hom
⊢ x✝ = PrimeSpectrum.comap (CommRingCat.Hom.hom (ΓSpecIso R).inv) ?x

Tactic:
· rw [RingHom.finrank_comp_left_of_bijective _ _ (ConcreteCategory.bijective_of_isIso _) hf₁ hf₂]

Goal state after:
case h1
R S : CommRingCat
f : R ⟶ S
hf₁✝ : IsFinite (Spec.map f)
hf₂✝ : Flat (Spec.map f)
hf₁ : (CommRingCat.Hom.hom (appTop (Spec.map f))).Finite
hf₂ : (CommRingCat.Hom.hom (appTop (Spec.map f))).Flat
x✝ : ↥(Spec R)
this : f = (ΓSpecIso R).inv ≫ appTop (Spec.map f) ≫ (ΓSpecIso S).hom
⊢ ((CommRingCat.Hom.hom (ΓSpecIso S).hom).comp (CommRingCat.Hom.hom (appTop (Spec.map f)))).Finite

case h2
R S : CommRingCat
f : R ⟶ S
hf₁✝ : IsFinite (Spec.map f)
hf₂✝ : Flat (Spec.map f)
hf₁ : (CommRingCat.Hom.hom (appTop (Spec.map f))).Finite
hf₂ : (CommRingCat.Hom.hom (appTop (Spec.map f))).Flat
x✝ : ↥(Spec R)
this : f = (ΓSpecIso R).inv ≫ appTop (Spec.map f) ≫ (ΓSpecIso S).hom
⊢ ((CommRingCat.Hom.hom (ΓSpecIso S).hom).comp (CommRingCat.Hom.hom (appTop (Spec.map f)))).Flat

case hy
R S : CommRingCat
f : R ⟶ S
hf₁✝ : IsFinite (Spec.map f)
hf₂✝ : Flat (Spec.map f)
hf₁ : (CommRingCat.Hom.hom (appTop (Spec.map f))).Finite
hf₂ : (CommRingCat.Hom.hom (appTop (Spec.map f))).Flat
x✝ : ↥(Spec R)
this : f = (ΓSpecIso R).inv ≫ appTop (Spec.map f) ≫ (ΓSpecIso S).hom
⊢ x✝ = PrimeSpectrum.comap (CommRingCat.Hom.hom (ΓSpecIso R).inv) ((Spec R).isoSpec.hom x✝)