Theorem: HomogeneousLocalization.Away.eventually_smul_mem
File: Mathlib/RingTheory/GradedAlgebra/HomogeneousLocalization.lean

Proof steps:
state_before: ι : Type u_1
R : Type u_2
A : Type u_3
inst✝⁵ : AddCommMonoid ι
inst✝⁴ : DecidableEq ι
inst✝³ : CommRing R
inst✝² : CommRing A
inst✝¹ : Algebra R A
𝒜 : ι → Submodule R A
inst✝ : GradedAlgebra 𝒜
x : Submonoid A
f : A
m : ι
hf : f ∈ 𝒜 m
z : Away 𝒜 f
⊢ ∀ᶠ (n : ℕ) in Filter.atTop, f ^ n • val z ∈ ⇑(algebraMap A (at Submonoid.powers f)) '' ↑(𝒜 (n • m))
state_after: case intro
ι : Type u_1
R : Type u_2
A : Type u_3
inst✝⁵ : AddCommMonoid ι
inst✝⁴ : DecidableEq ι
inst✝³ : CommRing R
inst✝² : CommRing A
inst✝¹ : Algebra R A
𝒜 : ι → Submodule R A
inst✝ : GradedAlgebra 𝒜
x : Submonoid A
f : A
m : ι
hf : f ∈ 𝒜 m
z : Away 𝒜 f
k : ℕ
hk : f ^ k = den z
⊢ ∀ᶠ (n : ℕ) in Filter.atTop, f ^ n • val z ∈ ⇑(algebraMap A (at Submonoid.powers f)) '' ↑(𝒜 (n • m))
tactic: obtain ⟨k, hk : f ^ k = _⟩ := z.den_mem
state_before: case intro
ι : Type u_1
R : Type u_2
A : Type u_3
inst✝⁵ : AddCommMonoid ι
inst✝⁴ : DecidableEq ι
inst✝³ : CommRing R
inst✝² : CommRing A
inst✝¹ : Algebra R A
𝒜 : ι → Submodule R A
inst✝ : GradedAlgebra 𝒜
x : Submonoid A
f : A
m : ι
hf : f ∈ 𝒜 m
z : Away 𝒜 f
k : ℕ
hk : f ^ k = den z
⊢ ∀ᶠ (n : ℕ) in Filter.atTop, f ^ n • val z ∈ ⇑(algebraMap A (at Submonoid.powers f)) '' ↑(𝒜 (n • m))
state_after: case intro
ι : Type u_1
R : Type u_2
A : Type u_3
inst✝⁵ : AddCommMonoid ι
inst✝⁴ : DecidableEq ι
inst✝³ : CommRing R
inst✝² : CommRing A
inst✝¹ : Algebra R A
𝒜 : ι → Submodule R A
inst✝ : GradedAlgebra 𝒜
x : Submonoid A
f : A
m : ι
hf : f ∈ 𝒜 m
z : Away 𝒜 f
k : ℕ
hk : f ^ k = den z
⊢ Set.Ici k ⊆ {x | (fun n => f ^ n • val z ∈ ⇑(algebraMap A (at Submonoid.powers f)) '' ↑(𝒜 (n • m))) x}
tactic: apply Filter.mem_of_superset (Filter.Ici_mem_atTop k)
state_before: case intro
ι : Type u_1
R : Type u_2
A : Type u_3
inst✝⁵ : AddCommMonoid ι
inst✝⁴ : DecidableEq ι
inst✝³ : CommRing R
inst✝² : CommRing A
inst✝¹ : Algebra R A
𝒜 : ι → Submodule R A
inst✝ : GradedAlgebra 𝒜
x : Submonoid A
f : A
m : ι
hf : f ∈ 𝒜 m
z : Away 𝒜 f
k : ℕ
hk : f ^ k = den z
⊢ Set.Ici k ⊆ {x | (fun n => f ^ n • val z ∈ ⇑(algebraMap A (at Submonoid.powers f)) '' ↑(𝒜 (n • m))) x}
state_after: case intro
ι : Type u_1
R : Type u_2
A : Type u_3
inst✝⁵ : AddCommMonoid ι
inst✝⁴ : DecidableEq ι
inst✝³ : CommRing R
inst✝² : CommRing A
inst✝¹ : Algebra R A
𝒜 : ι → Submodule R A
inst✝ : GradedAlgebra 𝒜
x : Submonoid A
f : A
m : ι
hf : f ∈ 𝒜 m
z : Away 𝒜 f
k : ℕ
hk : f ^ k = den z
k' : ℕ
hk' : k ≤ k'
⊢ k' ∈ {x | (fun n => f ^ n • val z ∈ ⇑(algebraMap A (at Submonoid.powers f)) '' ↑(𝒜 (n • m))) x}
tactic: rintro k' (hk' : k ≤ k')
state_before: case intro
ι : Type u_1
R : Type u_2
A : Type u_3
inst✝⁵ : AddCommMonoid ι
inst✝⁴ : DecidableEq ι
inst✝³ : CommRing R
inst✝² : CommRing A
inst✝¹ : Algebra R A
𝒜 : ι → Submodule R A
inst✝ : GradedAlgebra 𝒜
x : Submonoid A
f : A
m : ι
hf : f ∈ 𝒜 m
z : Away 𝒜 f
k : ℕ
hk : f ^ k = den z
k' : ℕ
hk' : k ≤ k'
⊢ k' ∈ {x | (fun n => f ^ n • val z ∈ ⇑(algebraMap A (at Submonoid.powers f)) '' ↑(𝒜 (n • m))) x}
state_after: case intro
ι : Type u_1
R : Type u_2
A : Type u_3
inst✝⁵ : AddCommMonoid ι
inst✝⁴ : DecidableEq ι
inst✝³ : CommRing R
inst✝² : CommRing A
inst✝¹ : Algebra R A
𝒜 : ι → Submodule R A
inst✝ : GradedAlgebra 𝒜
x : Submonoid A
f : A
m : ι
hf : f ∈ 𝒜 m
z : Away 𝒜 f
k : ℕ
hk : f ^ k = den z
k' : ℕ
hk' : k ≤ k'
⊢ ∃ x ∈ 𝒜 (k' • m), (algebraMap A (at Submonoid.powers f)) x = f ^ k' • val z
tactic: simp only [Set.mem_image, SetLike.mem_coe, Set.mem_setOf_eq]
state_before: case intro
ι : Type u_1
R : Type u_2
A : Type u_3
inst✝⁵ : AddCommMonoid ι
inst✝⁴ : DecidableEq ι
inst✝³ : CommRing R
inst✝² : CommRing A
inst✝¹ : Algebra R A
𝒜 : ι → Submodule R A
inst✝ : GradedAlgebra 𝒜
x : Submonoid A
f : A
m : ι
hf : f ∈ 𝒜 m
z : Away 𝒜 f
k : ℕ
hk : f ^ k = den z
k' : ℕ
hk' : k ≤ k'
⊢ ∃ x ∈ 𝒜 (k' • m), (algebraMap A (at Submonoid.powers f)) x = f ^ k' • val z
state_after: case pos
ι : Type u_1
R : Type u_2
A : Type u_3
inst✝⁵ : AddCommMonoid ι
inst✝⁴ : DecidableEq ι
inst✝³ : CommRing R
inst✝² : CommRing A
inst✝¹ : Algebra R A
𝒜 : ι → Submodule R A
inst✝ : GradedAlgebra 𝒜
x : Submonoid A
f : A
m : ι
hf : f ∈ 𝒜 m
z : Away 𝒜 f
k : ℕ
hk : f ^ k = den z
k' : ℕ
hk' : k ≤ k'
hfk : f ^ k = 0
⊢ ∃ x ∈ 𝒜 (k' • m), (algebraMap A (at Submonoid.powers f)) x = f ^ k' • val z

case neg
ι : Type u_1
R : Type u_2
A : Type u_3
inst✝⁵ : AddCommMonoid ι
inst✝⁴ : DecidableEq ι
inst✝³ : CommRing R
inst✝² : CommRing A
inst✝¹ : Algebra R A
𝒜 : ι → Submodule R A
inst✝ : GradedAlgebra 𝒜
x : Submonoid A
f : A
m : ι
hf : f ∈ 𝒜 m
z : Away 𝒜 f
k : ℕ
hk : f ^ k = den z
k' : ℕ
hk' : k ≤ k'
hfk : ¬f ^ k = 0
⊢ ∃ x ∈ 𝒜 (k' • m), (algebraMap A (at Submonoid.powers f)) x = f ^ k' • val z
tactic: by_cases hfk : f ^ k = 0
state_before: case neg
ι : Type u_1
R : Type u_2
A : Type u_3
inst✝⁵ : AddCommMonoid ι
inst✝⁴ : DecidableEq ι
inst✝³ : CommRing R
inst✝² : CommRing A
inst✝¹ : Algebra R A
𝒜 : ι → Submodule R A
inst✝ : GradedAlgebra 𝒜
x : Submonoid A
f : A
m : ι
hf : f ∈ 𝒜 m
z : Away 𝒜 f
k : ℕ
hk : f ^ k = den z
k' : ℕ
hk' : k ≤ k'
hfk : ¬f ^ k = 0
⊢ ∃ x ∈ 𝒜 (k' • m), (algebraMap A (at Submonoid.powers f)) x = f ^ k' • val z
state_after: case neg
ι : Type u_1
R : Type u_2
A : Type u_3
inst✝⁵ : AddCommMonoid ι
inst✝⁴ : DecidableEq ι
inst✝³ : CommRing R
inst✝² : CommRing A
inst✝¹ : Algebra R A
𝒜 : ι → Submodule R A
inst✝ : GradedAlgebra 𝒜
x : Submonoid A
f : A
m : ι
hf : f ∈ 𝒜 m
z : Away 𝒜 f
k : ℕ
hk : f ^ k = den z
k' : ℕ
hk' : k ≤ k'
hfk : ¬f ^ k = 0
⊢ ∃ x ∈ 𝒜 ((k' - k + k) • m),
    (algebraMap A (at Submonoid.powers f)) x = (algebraMap A (at Submonoid.powers f)) (f ^ (k' - k) * num z)
tactic: rw [← tsub_add_cancel_of_le hk', pow_add, mul_smul, hk, den_smul_val,
    Algebra.smul_def, ← _root_.map_mul]
state_before: case neg
ι : Type u_1
R : Type u_2
A : Type u_3
inst✝⁵ : AddCommMonoid ι
inst✝⁴ : DecidableEq ι
inst✝³ : CommRing R
inst✝² : CommRing A
inst✝¹ : Algebra R A
𝒜 : ι → Submodule R A
inst✝ : GradedAlgebra 𝒜
x : Submonoid A
f : A
m : ι
hf : f ∈ 𝒜 m
z : Away 𝒜 f
k : ℕ
hk : f ^ k = den z
k' : ℕ
hk' : k ≤ k'
hfk : ¬f ^ k = 0
⊢ ∃ x ∈ 𝒜 ((k' - k + k) • m),
    (algebraMap A (at Submonoid.powers f)) x = (algebraMap A (at Submonoid.powers f)) (f ^ (k' - k) * num z)
state_after: case neg
ι : Type u_1
R : Type u_2
A : Type u_3
inst✝⁵ : AddCommMonoid ι
inst✝⁴ : DecidableEq ι
inst✝³ : CommRing R
inst✝² : CommRing A
inst✝¹ : Algebra R A
𝒜 : ι → Submodule R A
inst✝ : GradedAlgebra 𝒜
x : Submonoid A
f : A
m : ι
hf : f ∈ 𝒜 m
z : Away 𝒜 f
k : ℕ
hk : f ^ k = den z
k' : ℕ
hk' : k ≤ k'
hfk : ¬f ^ k = 0
⊢ ∃ x ∈ 𝒜 ((k' - k) • m + deg z),
    (algebraMap A (at Submonoid.powers f)) x = (algebraMap A (at Submonoid.powers f)) (f ^ (k' - k) • num z)
tactic: rw [← smul_eq_mul, add_smul,
    DirectSum.degree_eq_of_mem_mem 𝒜 (SetLike.pow_mem_graded _ hf) (hk.symm ▸ z.den_mem_deg) hfk]
state_before: case neg
ι : Type u_1
R : Type u_2
A : Type u_3
inst✝⁵ : AddCommMonoid ι
inst✝⁴ : DecidableEq ι
inst✝³ : CommRing R
inst✝² : CommRing A
inst✝¹ : Algebra R A
𝒜 : ι → Submodule R A
inst✝ : GradedAlgebra 𝒜
x : Submonoid A
f : A
m : ι
hf : f ∈ 𝒜 m
z : Away 𝒜 f
k : ℕ
hk : f ^ k = den z
k' : ℕ
hk' : k ≤ k'
hfk : ¬f ^ k = 0
⊢ ∃ x ∈ 𝒜 ((k' - k) • m + deg z),
    (algebraMap A (at Submonoid.powers f)) x = (algebraMap A (at Submonoid.powers f)) (f ^ (k' - k) • num z)
state_after: no goals
tactic: exact ⟨_, SetLike.mul_mem_graded (SetLike.pow_mem_graded _ hf) z.num_mem_deg, rfl⟩