Module: Mathlib.AlgebraicGeometry.ProjectiveSpectrum.Scheme

Goal state before:
pp: A : Type u_1
σ : Type u_2
inst✝³ : CommRing A
inst✝² : SetLike σ A
inst✝¹ : AddSubgroupClass σ A
𝒜 : ℕ → σ
inst✝ : GradedRing 𝒜
f : A
x : ↥(pbo f)
m : ℕ
f_deg : f ∈ 𝒜 m
hm : 0 < m
this : Algebra (A⁰_ f) (AtPrime 𝒜 (↑x).asHomogeneousIdeal.toIdeal) := (mapId 𝒜 ⋯).toAlgebra
y z : NumDenSameDeg 𝒜 (Submonoid.powers f)
e :
  (algebraMap A (Localization (↑x).asHomogeneousIdeal.toIdeal.primeCompl)) (↑z.den * ↑y.num) =
    (algebraMap A (Localization (↑x).asHomogeneousIdeal.toIdeal.primeCompl)) (↑y.den * ↑z.num)
c : A
hcx : c ∈ (↑x).asHomogeneousIdeal.toIdeal.primeCompl
i : ℕ
hi : ↑(((decompose 𝒜) c) i) ∉ (↑x).asHomogeneousIdeal.toIdeal
hc :
  ↑(((decompose 𝒜) (↑⟨c, hcx⟩ * (↑z.den * ↑y.num))) (i + z.deg + y.deg)) =
    ↑(((decompose 𝒜) (↑⟨c, hcx⟩ * (↑y.den * ↑z.num))) (i + y.deg + z.deg))
⊢ ↑(((decompose 𝒜) c) i) * (↑z.den * ↑y.num) = ↑(((decompose 𝒜) c) i) * (↑y.den * ↑z.num)

Tactic:
rwa [← mul_assoc, coe_decompose_mul_add_of_right_mem, coe_decompose_mul_add_of_right_mem,
        ← mul_assoc, coe_decompose_mul_add_of_right_mem, coe_decompose_mul_add_of_right_mem,
        mul_assoc, mul_assoc] at hc

Goal state after:
case b_mem
A : Type u_1
σ : Type u_2
inst✝³ : CommRing A
inst✝² : SetLike σ A
inst✝¹ : AddSubgroupClass σ A
𝒜 : ℕ → σ
inst✝ : GradedRing 𝒜
f : A
x : ↥(pbo f)
m : ℕ
f_deg : f ∈ 𝒜 m
hm : 0 < m
this : Algebra (A⁰_ f) (AtPrime 𝒜 (↑x).asHomogeneousIdeal.toIdeal) := (mapId 𝒜 ⋯).toAlgebra
y z : NumDenSameDeg 𝒜 (Submonoid.powers f)
e :
  (algebraMap A (Localization (↑x).asHomogeneousIdeal.toIdeal.primeCompl)) (↑z.den * ↑y.num) =
    (algebraMap A (Localization (↑x).asHomogeneousIdeal.toIdeal.primeCompl)) (↑y.den * ↑z.num)
c : A
hcx : c ∈ (↑x).asHomogeneousIdeal.toIdeal.primeCompl
i : ℕ
hi : ↑(((decompose 𝒜) c) i) ∉ (↑x).asHomogeneousIdeal.toIdeal
hc : ↑(((decompose 𝒜) ↑⟨c, hcx⟩) i) * ↑z.den * ↑y.num = ↑(((decompose 𝒜) (↑⟨c, hcx⟩ * ↑y.den)) (i + y.deg)) * ↑z.num
⊢ ↑y.den ∈ 𝒜 y.deg

case b_mem
A : Type u_1
σ : Type u_2
inst✝³ : CommRing A
inst✝² : SetLike σ A
inst✝¹ : AddSubgroupClass σ A
𝒜 : ℕ → σ
inst✝ : GradedRing 𝒜
f : A
x : ↥(pbo f)
m : ℕ
f_deg : f ∈ 𝒜 m
hm : 0 < m
this : Algebra (A⁰_ f) (AtPrime 𝒜 (↑x).asHomogeneousIdeal.toIdeal) := (mapId 𝒜 ⋯).toAlgebra
y z : NumDenSameDeg 𝒜 (Submonoid.powers f)
e :
  (algebraMap A (Localization (↑x).asHomogeneousIdeal.toIdeal.primeCompl)) (↑z.den * ↑y.num) =
    (algebraMap A (Localization (↑x).asHomogeneousIdeal.toIdeal.primeCompl)) (↑y.den * ↑z.num)
c : A
hcx : c ∈ (↑x).asHomogeneousIdeal.toIdeal.primeCompl
i : ℕ
hi : ↑(((decompose 𝒜) c) i) ∉ (↑x).asHomogeneousIdeal.toIdeal
hc :
  ↑(((decompose 𝒜) ↑⟨c, hcx⟩) i) * ↑z.den * ↑y.num =
    ↑(((decompose 𝒜) (↑⟨c, hcx⟩ * ↑y.den * ↑z.num)) (i + y.deg + z.deg))
⊢ ↑z.num ∈ 𝒜 z.deg

case b_mem
A : Type u_1
σ : Type u_2
inst✝³ : CommRing A
inst✝² : SetLike σ A
inst✝¹ : AddSubgroupClass σ A
𝒜 : ℕ → σ
inst✝ : GradedRing 𝒜
f : A
x : ↥(pbo f)
m : ℕ
f_deg : f ∈ 𝒜 m
hm : 0 < m
this : Algebra (A⁰_ f) (AtPrime 𝒜 (↑x).asHomogeneousIdeal.toIdeal) := (mapId 𝒜 ⋯).toAlgebra
y z : NumDenSameDeg 𝒜 (Submonoid.powers f)
e :
  (algebraMap A (Localization (↑x).asHomogeneousIdeal.toIdeal.primeCompl)) (↑z.den * ↑y.num) =
    (algebraMap A (Localization (↑x).asHomogeneousIdeal.toIdeal.primeCompl)) (↑y.den * ↑z.num)
c : A
hcx : c ∈ (↑x).asHomogeneousIdeal.toIdeal.primeCompl
i : ℕ
hi : ↑(((decompose 𝒜) c) i) ∉ (↑x).asHomogeneousIdeal.toIdeal
hc :
  ↑(((decompose 𝒜) (↑⟨c, hcx⟩ * ↑z.den)) (i + z.deg)) * ↑y.num =
    ↑(((decompose 𝒜) (↑⟨c, hcx⟩ * (↑y.den * ↑z.num))) (i + y.deg + z.deg))
⊢ ↑z.den ∈ 𝒜 z.deg

case b_mem
A : Type u_1
σ : Type u_2
inst✝³ : CommRing A
inst✝² : SetLike σ A
inst✝¹ : AddSubgroupClass σ A
𝒜 : ℕ → σ
inst✝ : GradedRing 𝒜
f : A
x : ↥(pbo f)
m : ℕ
f_deg : f ∈ 𝒜 m
hm : 0 < m
this : Algebra (A⁰_ f) (AtPrime 𝒜 (↑x).asHomogeneousIdeal.toIdeal) := (mapId 𝒜 ⋯).toAlgebra
y z : NumDenSameDeg 𝒜 (Submonoid.powers f)
e :
  (algebraMap A (Localization (↑x).asHomogeneousIdeal.toIdeal.primeCompl)) (↑z.den * ↑y.num) =
    (algebraMap A (Localization (↑x).asHomogeneousIdeal.toIdeal.primeCompl)) (↑y.den * ↑z.num)
c : A
hcx : c ∈ (↑x).asHomogeneousIdeal.toIdeal.primeCompl
i : ℕ
hi : ↑(((decompose 𝒜) c) i) ∉ (↑x).asHomogeneousIdeal.toIdeal
hc :
  ↑(((decompose 𝒜) (↑⟨c, hcx⟩ * ↑z.den * ↑y.num)) (i + z.deg + y.deg)) =
    ↑(((decompose 𝒜) (↑⟨c, hcx⟩ * (↑y.den * ↑z.num))) (i + y.deg + z.deg))
⊢ ↑y.num ∈ 𝒜 y.deg