Module: Mathlib.NumberTheory.Cyclotomic.Basic

Goal state before:
pp: case refine_2
n : ℕ
inst✝¹⁰ : NeZero n
S T : Set ℕ
A : Type u
B : Type v
K : Type w
L : Type z
inst✝⁹ : CommRing A
inst✝⁸ : CommRing B
inst✝⁷ : Algebra A B
inst✝⁶ : Field K
inst✝⁵ : Field L
inst✝⁴ : Algebra K L
inst✝³ : Algebra A K
inst✝² : IsFractionRing A K
inst✝¹ : IsDomain A
inst✝ : NeZero ↑n
x : CyclotomicField n K
this : NeZero ↑n
k : K
⊢ ∃ x,
    (algebraMap K (CyclotomicField n K)) k * (algebraMap (CyclotomicRing n A K) (CyclotomicField n K)) ↑x.2 =
      (algebraMap (CyclotomicRing n A K) (CyclotomicField n K)) x.1

pp: case refine_3
n : ℕ
inst✝¹⁰ : NeZero n
S T : Set ℕ
A : Type u
B : Type v
K : Type w
L : Type z
inst✝⁹ : CommRing A
inst✝⁸ : CommRing B
inst✝⁷ : Algebra A B
inst✝⁶ : Field K
inst✝⁵ : Field L
inst✝⁴ : Algebra K L
inst✝³ : Algebra A K
inst✝² : IsFractionRing A K
inst✝¹ : IsDomain A
inst✝ : NeZero ↑n
x : CyclotomicField n K
this : NeZero ↑n
⊢ ∀ (x y : CyclotomicField n K),
    x ∈ adjoin K {b | b ^ n = 1} →
      y ∈ adjoin K {b | b ^ n = 1} →
        (∃ x_1,
            x * (algebraMap (CyclotomicRing n A K) (CyclotomicField n K)) ↑x_1.2 =
              (algebraMap (CyclotomicRing n A K) (CyclotomicField n K)) x_1.1) →
          (∃ x,
              y * (algebraMap (CyclotomicRing n A K) (CyclotomicField n K)) ↑x.2 =
                (algebraMap (CyclotomicRing n A K) (CyclotomicField n K)) x.1) →
            ∃ x_1,
              (x + y) * (algebraMap (CyclotomicRing n A K) (CyclotomicField n K)) ↑x_1.2 =
                (algebraMap (CyclotomicRing n A K) (CyclotomicField n K)) x_1.1

pp: case refine_4
n : ℕ
inst✝¹⁰ : NeZero n
S T : Set ℕ
A : Type u
B : Type v
K : Type w
L : Type z
inst✝⁹ : CommRing A
inst✝⁸ : CommRing B
inst✝⁷ : Algebra A B
inst✝⁶ : Field K
inst✝⁵ : Field L
inst✝⁴ : Algebra K L
inst✝³ : Algebra A K
inst✝² : IsFractionRing A K
inst✝¹ : IsDomain A
inst✝ : NeZero ↑n
x : CyclotomicField n K
this : NeZero ↑n
⊢ ∀ (x y : CyclotomicField n K),
    x ∈ adjoin K {b | b ^ n = 1} →
      y ∈ adjoin K {b | b ^ n = 1} →
        (∃ x_1,
            x * (algebraMap (CyclotomicRing n A K) (CyclotomicField n K)) ↑x_1.2 =
              (algebraMap (CyclotomicRing n A K) (CyclotomicField n K)) x_1.1) →
          (∃ x,
              y * (algebraMap (CyclotomicRing n A K) (CyclotomicField n K)) ↑x.2 =
                (algebraMap (CyclotomicRing n A K) (CyclotomicField n K)) x.1) →
            ∃ x_1,
              x * y * (algebraMap (CyclotomicRing n A K) (CyclotomicField n K)) ↑x_1.2 =
                (algebraMap (CyclotomicRing n A K) (CyclotomicField n K)) x_1.1

Tactic:
· have : IsLocalization (nonZeroDivisors A) K := inferInstance
      replace := this.surj
      obtain ⟨⟨z, w⟩, hw⟩ := this k
      refine ⟨⟨algebraMap A (CyclotomicRing n A K) z, algebraMap A (CyclotomicRing n A K) w,
        map_mem_nonZeroDivisors _ (algebraBase_injective n A K) w.2⟩, ?_⟩
      let : IsScalarTower A K (CyclotomicField n K) :=
        IsScalarTower.of_algebraMap_eq (congr_fun rfl)
      rw [← IsScalarTower.algebraMap_apply, ← IsScalarTower.algebraMap_apply,
        @IsScalarTower.algebraMap_apply A K _ _ _ _ _ (_root_.CyclotomicField.algebra n K) _ _ w,
        ← map_mul, hw, ← IsScalarTower.algebraMap_apply]

Goal state after:
case refine_3
n : ℕ
inst✝¹⁰ : NeZero n
S T : Set ℕ
A : Type u
B : Type v
K : Type w
L : Type z
inst✝⁹ : CommRing A
inst✝⁸ : CommRing B
inst✝⁷ : Algebra A B
inst✝⁶ : Field K
inst✝⁵ : Field L
inst✝⁴ : Algebra K L
inst✝³ : Algebra A K
inst✝² : IsFractionRing A K
inst✝¹ : IsDomain A
inst✝ : NeZero ↑n
x : CyclotomicField n K
this : NeZero ↑n
⊢ ∀ (x y : CyclotomicField n K),
    x ∈ adjoin K {b | b ^ n = 1} →
      y ∈ adjoin K {b | b ^ n = 1} →
        (∃ x_1,
            x * (algebraMap (CyclotomicRing n A K) (CyclotomicField n K)) ↑x_1.2 =
              (algebraMap (CyclotomicRing n A K) (CyclotomicField n K)) x_1.1) →
          (∃ x,
              y * (algebraMap (CyclotomicRing n A K) (CyclotomicField n K)) ↑x.2 =
                (algebraMap (CyclotomicRing n A K) (CyclotomicField n K)) x.1) →
            ∃ x_1,
              (x + y) * (algebraMap (CyclotomicRing n A K) (CyclotomicField n K)) ↑x_1.2 =
                (algebraMap (CyclotomicRing n A K) (CyclotomicField n K)) x_1.1

case refine_4
n : ℕ
inst✝¹⁰ : NeZero n
S T : Set ℕ
A : Type u
B : Type v
K : Type w
L : Type z
inst✝⁹ : CommRing A
inst✝⁸ : CommRing B
inst✝⁷ : Algebra A B
inst✝⁶ : Field K
inst✝⁵ : Field L
inst✝⁴ : Algebra K L
inst✝³ : Algebra A K
inst✝² : IsFractionRing A K
inst✝¹ : IsDomain A
inst✝ : NeZero ↑n
x : CyclotomicField n K
this : NeZero ↑n
⊢ ∀ (x y : CyclotomicField n K),
    x ∈ adjoin K {b | b ^ n = 1} →
      y ∈ adjoin K {b | b ^ n = 1} →
        (∃ x_1,
            x * (algebraMap (CyclotomicRing n A K) (CyclotomicField n K)) ↑x_1.2 =
              (algebraMap (CyclotomicRing n A K) (CyclotomicField n K)) x_1.1) →
          (∃ x,
              y * (algebraMap (CyclotomicRing n A K) (CyclotomicField n K)) ↑x.2 =
                (algebraMap (CyclotomicRing n A K) (CyclotomicField n K)) x.1) →
            ∃ x_1,
              x * y * (algebraMap (CyclotomicRing n A K) (CyclotomicField n K)) ↑x_1.2 =
                (algebraMap (CyclotomicRing n A K) (CyclotomicField n K)) x_1.1