-- Mathlib/AlgebraicGeometry/ProjectiveSpectrum/Scheme.lean
theorem mem_carrier_iff_of_mem_mul (hm : 0 < m)
    (q : Spec.T A⁰_ f) (a : A) {n} (hn : a ∈ 𝒜 (n * m)) :
    a ∈ carrier f_deg q ↔ (HomogeneousLocalization.mk ⟨m * n, ⟨a, mul_comm n m ▸ hn⟩,
        ⟨f ^ n, by rw [mul_comm]; mem_tac⟩, ⟨_, rfl⟩⟩ : A⁰_ f) ∈ q.asIdeal

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
m : ℕ
f_deg : f ∈ 𝒜 m
hm : 0 < m
q : ↑↑(Spec A⁰_ f).toPresheafedSpace
a : A
n : ℕ
hn : a ∈ 𝒜 (n * m)
⊢ f ^ n ∈ 𝒜 (n * m)

Tactic:
mem_tac

Result:
no goals

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
m : ℕ
f_deg : f ∈ 𝒜 m
hm : 0 < m
q : ↑↑(Spec A⁰_ f).toPresheafedSpace
a : A
n : ℕ
hn : a ∈ 𝒜 (n * m)
⊢ (HomogeneousLocalization.mk { deg := m * n, num := ⟨a, ⋯⟩, den := ⟨f ^ n, ⋯⟩, den_mem := ⋯ } ^ m ∈ q.asIdeal) =
    (HomogeneousLocalization.mk { deg := m * (n * m), num := ⟨a ^ m, ⋯⟩, den := ⟨f ^ (n * m), ⋯⟩, den_mem := ⋯ } ∈
      q.asIdeal)

Tactic:
congr 1

Result:
case e_a
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
m : ℕ
f_deg : f ∈ 𝒜 m
hm : 0 < m
q : ↑↑(Spec A⁰_ f).toPresheafedSpace
a : A
n : ℕ
hn : a ∈ 𝒜 (n * m)
⊢ HomogeneousLocalization.mk { deg := m * n, num := ⟨a, ⋯⟩, den := ⟨f ^ n, ⋯⟩, den_mem := ⋯ } ^ m =
    HomogeneousLocalization.mk { deg := m * (n * m), num := ⟨a ^ m, ⋯⟩, den := ⟨f ^ (n * m), ⋯⟩, den_mem := ⋯ }

Proof state:
case e_a.a
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
m : ℕ
f_deg : f ∈ 𝒜 m
hm : 0 < m
q : ↑↑(Spec A⁰_ f).toPresheafedSpace
a : A
n : ℕ
hn : a ∈ 𝒜 (n * m)
⊢ Localization.mk (a ^ m) (⟨f ^ n, ⋯⟩ ^ m) = Localization.mk (a ^ m) ⟨(f ^ n) ^ m, ⋯⟩

Tactic:
rfl

Result:
no goals

Proof state:
case e_a.a
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
m : ℕ
f_deg : f ∈ 𝒜 m
hm : 0 < m
q : ↑↑(Spec A⁰_ f).toPresheafedSpace
a : A
n : ℕ
hn : a ∈ 𝒜 (n * m)
⊢ HomogeneousLocalization.val
      (HomogeneousLocalization.mk { deg := m * n, num := ⟨a, ⋯⟩, den := ⟨f ^ n, ⋯⟩, den_mem := ⋯ } ^ m) =
    (HomogeneousLocalization.mk { deg := m * (n * m), num := ⟨a ^ m, ⋯⟩, den := ⟨f ^ (n * m), ⋯⟩, den_mem := ⋯ }).val

Tactic:
simp only [HomogeneousLocalization.val_mk, HomogeneousLocalization.val_pow,
  Localization.mk_pow, pow_mul]

Result:
case e_a.a
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
m : ℕ
f_deg : f ∈ 𝒜 m
hm : 0 < m
q : ↑↑(Spec A⁰_ f).toPresheafedSpace
a : A
n : ℕ
hn : a ∈ 𝒜 (n * m)
⊢ Localization.mk (a ^ m) (⟨f ^ n, ⋯⟩ ^ m) = Localization.mk (a ^ m) ⟨(f ^ n) ^ m, ⋯⟩

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
m : ℕ
f_deg : f ∈ 𝒜 m
hm : 0 < m
q : ↑↑(Spec A⁰_ f).toPresheafedSpace
a : A
n : ℕ
hn : a ∈ 𝒜 (n * m)
⊢ a ∈ carrier f_deg q ↔
    HomogeneousLocalization.mk { deg := m * n, num := ⟨a, ⋯⟩, den := ⟨f ^ n, ⋯⟩, den_mem := ⋯ } ∈ q.asIdeal

Tactic:
rw [mem_carrier_iff_of_mem f_deg hm q a hn, iff_iff_eq, eq_comm,
  ← Ideal.IsPrime.pow_mem_iff_mem (α := A⁰_ f) inferInstance m hm]

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
m : ℕ
f_deg : f ∈ 𝒜 m
hm : 0 < m
q : ↑↑(Spec A⁰_ f).toPresheafedSpace
a : A
n : ℕ
hn : a ∈ 𝒜 (n * m)
⊢ (HomogeneousLocalization.mk { deg := m * n, num := ⟨a, ⋯⟩, den := ⟨f ^ n, ⋯⟩, den_mem := ⋯ } ^ m ∈ q.asIdeal) =
    (HomogeneousLocalization.mk { deg := m * (n * m), num := ⟨a ^ m, ⋯⟩, den := ⟨f ^ (n * m), ⋯⟩, den_mem := ⋯ } ∈
      q.asIdeal)

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
m : ℕ
f_deg : f ∈ 𝒜 m
hm : 0 < m
q : ↑↑(Spec A⁰_ f).toPresheafedSpace
a : A
n : ℕ
hn : a ∈ 𝒜 (n * m)
⊢ f ^ n ∈ 𝒜 (m * n)

Tactic:
rw [mul_comm]

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
m : ℕ
f_deg : f ∈ 𝒜 m
hm : 0 < m
q : ↑↑(Spec A⁰_ f).toPresheafedSpace
a : A
n : ℕ
hn : a ∈ 𝒜 (n * m)
⊢ f ^ n ∈ 𝒜 (n * m)

Proof state:
case e_a
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
m : ℕ
f_deg : f ∈ 𝒜 m
hm : 0 < m
q : ↑↑(Spec A⁰_ f).toPresheafedSpace
a : A
n : ℕ
hn : a ∈ 𝒜 (n * m)
⊢ HomogeneousLocalization.mk { deg := m * n, num := ⟨a, ⋯⟩, den := ⟨f ^ n, ⋯⟩, den_mem := ⋯ } ^ m =
    HomogeneousLocalization.mk { deg := m * (n * m), num := ⟨a ^ m, ⋯⟩, den := ⟨f ^ (n * m), ⋯⟩, den_mem := ⋯ }

Tactic:
apply HomogeneousLocalization.val_injective

Result:
case e_a.a
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
m : ℕ
f_deg : f ∈ 𝒜 m
hm : 0 < m
q : ↑↑(Spec A⁰_ f).toPresheafedSpace
a : A
n : ℕ
hn : a ∈ 𝒜 (n * m)
⊢ HomogeneousLocalization.val
      (HomogeneousLocalization.mk { deg := m * n, num := ⟨a, ⋯⟩, den := ⟨f ^ n, ⋯⟩, den_mem := ⋯ } ^ m) =
    (HomogeneousLocalization.mk { deg := m * (n * m), num := ⟨a ^ m, ⋯⟩, den := ⟨f ^ (n * m), ⋯⟩, den_mem := ⋯ }).val