-- Mathlib/NumberTheory/Cyclotomic/Rat.lean
theorem isIntegralClosure_adjoin_singleton_of_prime_pow [hcycl : IsCyclotomicExtension {p ^ k} ℚ K]
    (hζ : IsPrimitiveRoot ζ ↑(p ^ k)) : IsIntegralClosure (adjoin ℤ ({ζ} : Set K)) ℤ K

Proof state:
case refine_1.intro.intro.zero
p : ℕ+
K : Type u
inst✝¹ : Field K
ζ : K
hp : Fact (Nat.Prime ↑p)
inst✝ : CharZero K
x : K
h : IsIntegral ℤ x
u : ℤˣ
n : ℕ
hcycl : IsCyclotomicExtension {p ^ 0} ℚ K
hζ : IsPrimitiveRoot ζ ↑(p ^ 0)
B : PowerBasis ℚ K := IsPrimitiveRoot.subOnePowerBasis ℚ hζ
hint : IsIntegral ℤ B.gen
this : FiniteDimensional ℚ K := finiteDimensional {p ^ 0} ℚ K
hun : Algebra.discr ℚ ⇑(IsPrimitiveRoot.subOnePowerBasis ℚ hζ).basis = ↑↑u * ↑↑p ^ n
H : (algebraMap ℚ K) ↑↑p ^ n * x ∈ adjoin ℤ {B.gen}
⊢ x ∈ adjoin ℤ {ζ}

Tactic:
haveI : IsCyclotomicExtension {1} ℚ K := by simpa using hcycl

Result:
case refine_1.intro.intro.zero
p : ℕ+
K : Type u
inst✝¹ : Field K
ζ : K
hp : Fact (Nat.Prime ↑p)
inst✝ : CharZero K
x : K
h : IsIntegral ℤ x
u : ℤˣ
n : ℕ
hcycl : IsCyclotomicExtension {p ^ 0} ℚ K
hζ : IsPrimitiveRoot ζ ↑(p ^ 0)
B : PowerBasis ℚ K := IsPrimitiveRoot.subOnePowerBasis ℚ hζ
hint : IsIntegral ℤ B.gen
this✝ : FiniteDimensional ℚ K := finiteDimensional {p ^ 0} ℚ K
hun : Algebra.discr ℚ ⇑(IsPrimitiveRoot.subOnePowerBasis ℚ hζ).basis = ↑↑u * ↑↑p ^ n
H : (algebraMap ℚ K) ↑↑p ^ n * x ∈ adjoin ℤ {B.gen}
this : IsCyclotomicExtension {1} ℚ K
⊢ x ∈ adjoin ℤ {ζ}

Proof state:
case refine_1.intro.intro
p : ℕ+
k : ℕ
K : Type u
inst✝¹ : Field K
ζ : K
hp : Fact (Nat.Prime ↑p)
inst✝ : CharZero K
hcycl : IsCyclotomicExtension {p ^ k} ℚ K
hζ : IsPrimitiveRoot ζ ↑(p ^ k)
x : K
h : IsIntegral ℤ x
B : PowerBasis ℚ K := IsPrimitiveRoot.subOnePowerBasis ℚ hζ
hint : IsIntegral ℤ B.gen
this : FiniteDimensional ℚ K := finiteDimensional {p ^ k} ℚ K
u : ℤˣ
n : ℕ
hun : Algebra.discr ℚ ⇑(IsPrimitiveRoot.subOnePowerBasis ℚ hζ).basis = ↑↑u * ↑↑p ^ n
H : u.inv • (↑↑u * ↑↑p ^ n) • x ∈ adjoin ℤ {B.gen}
⊢ x ∈ adjoin ℤ {ζ}

Tactic:
rw [← smul_assoc, ← smul_mul_assoc, Units.inv_eq_val_inv, zsmul_eq_mul, ← Int.cast_mul,
  Units.inv_mul, Int.cast_one, one_mul, smul_def, map_pow] at H

Result:
case refine_1.intro.intro
p : ℕ+
k : ℕ
K : Type u
inst✝¹ : Field K
ζ : K
hp : Fact (Nat.Prime ↑p)
inst✝ : CharZero K
hcycl : IsCyclotomicExtension {p ^ k} ℚ K
hζ : IsPrimitiveRoot ζ ↑(p ^ k)
x : K
h : IsIntegral ℤ x
B : PowerBasis ℚ K := IsPrimitiveRoot.subOnePowerBasis ℚ hζ
hint : IsIntegral ℤ B.gen
this : FiniteDimensional ℚ K := finiteDimensional {p ^ k} ℚ K
u : ℤˣ
n : ℕ
hun : Algebra.discr ℚ ⇑(IsPrimitiveRoot.subOnePowerBasis ℚ hζ).basis = ↑↑u * ↑↑p ^ n
H : (algebraMap ℚ K) ↑↑p ^ n * x ∈ adjoin ℤ {B.gen}
⊢ x ∈ adjoin ℤ {ζ}

Proof state:
p : ℕ+
K : Type u
inst✝¹ : Field K
ζ : K
hp : Fact (Nat.Prime ↑p)
inst✝ : CharZero K
x : K
h : IsIntegral ℤ x
u : ℤˣ
n n✝ : ℕ
hcycl : IsCyclotomicExtension {p ^ (n✝ + 1)} ℚ K
hζ : IsPrimitiveRoot ζ ↑(p ^ (n✝ + 1))
B : PowerBasis ℚ K := IsPrimitiveRoot.subOnePowerBasis ℚ hζ
hint : IsIntegral ℤ B.gen
this : FiniteDimensional ℚ K := finiteDimensional {p ^ (n✝ + 1)} ℚ K
hun : Algebra.discr ℚ ⇑(IsPrimitiveRoot.subOnePowerBasis ℚ hζ).basis = ↑↑u * ↑↑p ^ n
H : (algebraMap ℚ K) ↑↑p ^ n * x ∈ adjoin ℤ {B.gen}
⊢ (minpoly ℤ B.gen).IsEisensteinAt (Submodule.span ℤ {↑↑p})

Tactic:
have h₁ := minpoly.isIntegrallyClosed_eq_field_fractions' ℚ hint

Result:
p : ℕ+
K : Type u
inst✝¹ : Field K
ζ : K
hp : Fact (Nat.Prime ↑p)
inst✝ : CharZero K
x : K
h : IsIntegral ℤ x
u : ℤˣ
n n✝ : ℕ
hcycl : IsCyclotomicExtension {p ^ (n✝ + 1)} ℚ K
hζ : IsPrimitiveRoot ζ ↑(p ^ (n✝ + 1))
B : PowerBasis ℚ K := IsPrimitiveRoot.subOnePowerBasis ℚ hζ
hint : IsIntegral ℤ B.gen
this : FiniteDimensional ℚ K := finiteDimensional {p ^ (n✝ + 1)} ℚ K
hun : Algebra.discr ℚ ⇑(IsPrimitiveRoot.subOnePowerBasis ℚ hζ).basis = ↑↑u * ↑↑p ^ n
H : (algebraMap ℚ K) ↑↑p ^ n * x ∈ adjoin ℤ {B.gen}
h₁ : minpoly ℚ B.gen = map (algebraMap ℤ ℚ) (minpoly ℤ B.gen)
⊢ (minpoly ℤ B.gen).IsEisensteinAt (Submodule.span ℤ {↑↑p})

Proof state:
case refine_2.intro
p : ℕ+
k : ℕ
K : Type u
inst✝¹ : Field K
ζ : K
hp : Fact (Nat.Prime ↑p)
inst✝ : CharZero K
hcycl : IsCyclotomicExtension {p ^ k} ℚ K
hζ : IsPrimitiveRoot ζ ↑(p ^ k)
y : ↥(adjoin ℤ {ζ})
⊢ IsIntegral ℤ ((algebraMap (↥(adjoin ℤ {ζ})) K) y)

Tactic:
exact
  IsIntegral.algebraMap
    ((le_integralClosure_iff_isIntegral.1
      (adjoin_le_integralClosure (hζ.isIntegral (p ^ k).pos))).isIntegral _)

Result:
no goals

Proof state:
p : ℕ+
K : Type u
inst✝¹ : Field K
ζ : K
hp : Fact (Nat.Prime ↑p)
inst✝ : CharZero K
x : K
h : IsIntegral ℤ x
u : ℤˣ
n : ℕ
hcycl : IsCyclotomicExtension {p ^ 0} ℚ K
hζ : IsPrimitiveRoot ζ ↑(p ^ 0)
B : PowerBasis ℚ K := IsPrimitiveRoot.subOnePowerBasis ℚ hζ
hint : IsIntegral ℤ B.gen
this : FiniteDimensional ℚ K := finiteDimensional {p ^ 0} ℚ K
hun : Algebra.discr ℚ ⇑(IsPrimitiveRoot.subOnePowerBasis ℚ hζ).basis = ↑↑u * ↑↑p ^ n
H : (algebraMap ℚ K) ↑↑p ^ n * x ∈ adjoin ℤ {B.gen}
⊢ IsCyclotomicExtension {1} ℚ K

Tactic:
simpa using hcycl

Result:
no goals

Proof state:
case refine_1.intro.intro.zero
p : ℕ+
K : Type u
inst✝¹ : Field K
ζ : K
hp : Fact (Nat.Prime ↑p)
inst✝ : CharZero K
x : K
h : IsIntegral ℤ x
u : ℤˣ
n : ℕ
hcycl : IsCyclotomicExtension {p ^ 0} ℚ K
hζ : IsPrimitiveRoot ζ ↑(p ^ 0)
B : PowerBasis ℚ K := IsPrimitiveRoot.subOnePowerBasis ℚ hζ
hint : IsIntegral ℤ B.gen
this✝ : FiniteDimensional ℚ K := finiteDimensional {p ^ 0} ℚ K
hun : Algebra.discr ℚ ⇑(IsPrimitiveRoot.subOnePowerBasis ℚ hζ).basis = ↑↑u * ↑↑p ^ n
H : (algebraMap ℚ K) ↑↑p ^ n * x ∈ adjoin ℤ {B.gen}
this : IsCyclotomicExtension {1} ℚ K
⊢ x ∈ adjoin ℤ {ζ}

Tactic:
have : x ∈ (⊥ : Subalgebra ℚ K) := by
  rw [singleton_one ℚ K]
  exact mem_top

Result:
case refine_1.intro.intro.zero
p : ℕ+
K : Type u
inst✝¹ : Field K
ζ : K
hp : Fact (Nat.Prime ↑p)
inst✝ : CharZero K
x : K
h : IsIntegral ℤ x
u : ℤˣ
n : ℕ
hcycl : IsCyclotomicExtension {p ^ 0} ℚ K
hζ : IsPrimitiveRoot ζ ↑(p ^ 0)
B : PowerBasis ℚ K := IsPrimitiveRoot.subOnePowerBasis ℚ hζ
hint : IsIntegral ℤ B.gen
this✝¹ : FiniteDimensional ℚ K := finiteDimensional {p ^ 0} ℚ K
hun : Algebra.discr ℚ ⇑(IsPrimitiveRoot.subOnePowerBasis ℚ hζ).basis = ↑↑u * ↑↑p ^ n
H : (algebraMap ℚ K) ↑↑p ^ n * x ∈ adjoin ℤ {B.gen}
this✝ : IsCyclotomicExtension {1} ℚ K
this : x ∈ ⊥
⊢ x ∈ adjoin ℤ {ζ}

Proof state:
case refine_1.intro.intro
p : ℕ+
k : ℕ
K : Type u
inst✝¹ : Field K
ζ : K
hp : Fact (Nat.Prime ↑p)
inst✝ : CharZero K
hcycl : IsCyclotomicExtension {p ^ k} ℚ K
hζ : IsPrimitiveRoot ζ ↑(p ^ k)
x : K
h : IsIntegral ℤ x
B : PowerBasis ℚ K := IsPrimitiveRoot.subOnePowerBasis ℚ hζ
hint : IsIntegral ℤ B.gen
this : FiniteDimensional ℚ K := finiteDimensional {p ^ k} ℚ K
u : ℤˣ
n : ℕ
H : (↑↑u * ↑↑p ^ n) • x ∈ adjoin ℤ {B.gen}
hun : Algebra.discr ℚ ⇑(IsPrimitiveRoot.subOnePowerBasis ℚ hζ).basis = ↑↑u * ↑↑p ^ n
⊢ x ∈ adjoin ℤ {ζ}

Tactic:
replace H := Subalgebra.smul_mem _ H u.inv

Result:
case refine_1.intro.intro
p : ℕ+
k : ℕ
K : Type u
inst✝¹ : Field K
ζ : K
hp : Fact (Nat.Prime ↑p)
inst✝ : CharZero K
hcycl : IsCyclotomicExtension {p ^ k} ℚ K
hζ : IsPrimitiveRoot ζ ↑(p ^ k)
x : K
h : IsIntegral ℤ x
B : PowerBasis ℚ K := IsPrimitiveRoot.subOnePowerBasis ℚ hζ
hint : IsIntegral ℤ B.gen
this : FiniteDimensional ℚ K := finiteDimensional {p ^ k} ℚ K
u : ℤˣ
n : ℕ
hun : Algebra.discr ℚ ⇑(IsPrimitiveRoot.subOnePowerBasis ℚ hζ).basis = ↑↑u * ↑↑p ^ n
H : u.inv • (↑↑u * ↑↑p ^ n) • x ∈ adjoin ℤ {B.gen}
⊢ x ∈ adjoin ℤ {ζ}