-- Mathlib/RingTheory/Polynomial/Cyclotomic/Eval.lean
theorem cyclotomic_eval_lt_add_one_pow_totient {n : ℕ} {q : ℝ} (hn' : 3 ≤ n) (hq' : 1 < q) :
    (cyclotomic n ℝ).eval q < (q + 1) ^ totient n

Proof state:
n : ℕ
q : ℝ
hn' : 3 ≤ n
hq' : 1 < q
hn : 0 < n
hq : 0 < q
hfor : ∀ ζ' ∈ primitiveRoots n ℂ, ‖↑q - ζ'‖ ≤ q + 1
ζ : ℂ := Complex.exp (2 * ↑Real.pi * Complex.I / ↑n)
hζ : IsPrimitiveRoot ζ n
hex : ∃ ζ' ∈ primitiveRoots n ℂ, ‖↑q - ζ'‖ < q + 1
this✝ : ¬eval (↑q) (cyclotomic n ℂ) = 0
this : ‖eval (↑q) (cyclotomic n ℂ)‖ < ((q + 1) ⊔ 0) ^ φ n
⊢ eval q (cyclotomic n ℝ) < (q + 1) ^ φ n

Tactic:
convert this using 2

Result:
case h.e'_3
n : ℕ
q : ℝ
hn' : 3 ≤ n
hq' : 1 < q
hn : 0 < n
hq : 0 < q
hfor : ∀ ζ' ∈ primitiveRoots n ℂ, ‖↑q - ζ'‖ ≤ q + 1
ζ : ℂ := Complex.exp (2 * ↑Real.pi * Complex.I / ↑n)
hζ : IsPrimitiveRoot ζ n
hex : ∃ ζ' ∈ primitiveRoots n ℂ, ‖↑q - ζ'‖ < q + 1
this✝ : ¬eval (↑q) (cyclotomic n ℂ) = 0
this : ‖eval (↑q) (cyclotomic n ℂ)‖ < ((q + 1) ⊔ 0) ^ φ n
⊢ eval q (cyclotomic n ℝ) = ‖eval (↑q) (cyclotomic n ℂ)‖

case h.e'_4.h.e'_5
n : ℕ
q : ℝ
hn' : 3 ≤ n
hq' : 1 < q
hn : 0 < n
hq : 0 < q
hfor : ∀ ζ' ∈ primitiveRoots n ℂ, ‖↑q - ζ'‖ ≤ q + 1
ζ : ℂ := Complex.exp (2 * ↑Real.pi * Complex.I / ↑n)
hζ : IsPrimitiveRoot ζ n
hex : ∃ ζ' ∈ primitiveRoots n ℂ, ‖↑q - ζ'‖ < q + 1
this✝ : ¬eval (↑q) (cyclotomic n ℂ) = 0
this : ‖eval (↑q) (cyclotomic n ℂ)‖ < ((q + 1) ⊔ 0) ^ φ n
⊢ q + 1 = (q + 1) ⊔ 0

Proof state:
case h.e'_4.h.e'_5
n : ℕ
q : ℝ
hn' : 3 ≤ n
hq' : 1 < q
hn : 0 < n
hq : 0 < q
hfor : ∀ ζ' ∈ primitiveRoots n ℂ, ‖↑q - ζ'‖ ≤ q + 1
ζ : ℂ := Complex.exp (2 * ↑Real.pi * Complex.I / ↑n)
hζ : IsPrimitiveRoot ζ n
this : ¬SameRay ℝ (↑q) (-ζ)
⊢ ‖q‖ = q

Tactic:
exact abs_eq_self.mpr hq.le

Result:
no goals

Proof state:
n : ℕ
q : ℝ
hn' : 3 ≤ n
hq' : 1 < q
hn : 0 < n
hq : 0 < q
hfor : ∀ ζ' ∈ primitiveRoots n ℂ, ‖↑q - ζ'‖ ≤ q + 1
ζ : ℂ := Complex.exp (2 * ↑Real.pi * Complex.I / ↑n)
hζ : IsPrimitiveRoot ζ n
hex : ∃ ζ' ∈ primitiveRoots n ℂ, ‖↑q - ζ'‖ < q + 1
this : ¬eval (↑q) (cyclotomic n ℂ) = 0
x✝ : { x // x ∈ primitiveRoots n ℂ }
⊢ 0 < q + 1

Tactic:
linarith only [hq']

Result:
no goals

Proof state:
case convert_5
n : ℕ
q : ℝ
hn' : 3 ≤ n
hq' : 1 < q
hn : 0 < n
hq : 0 < q
hfor : ∀ ζ' ∈ primitiveRoots n ℂ, ‖↑q - ζ'‖ ≤ q + 1
ζ : ℂ := Complex.exp (2 * ↑Real.pi * Complex.I / ↑n)
hζ : IsPrimitiveRoot ζ n
hex : ∃ ζ' ∈ primitiveRoots n ℂ, ‖↑q - ζ'‖ < q + 1
this : ¬eval (↑q) (cyclotomic n ℂ) = 0
x : ℂ
hx : x ∈ primitiveRoots n ℂ
⊢ ‖↑q - x‖ ≤ ↑(q + 1).toNNReal

Tactic:
have : ‖_‖ ≤ _ := hfor x hx

Result:
case convert_5
n : ℕ
q : ℝ
hn' : 3 ≤ n
hq' : 1 < q
hn : 0 < n
hq : 0 < q
hfor : ∀ ζ' ∈ primitiveRoots n ℂ, ‖↑q - ζ'‖ ≤ q + 1
ζ : ℂ := Complex.exp (2 * ↑Real.pi * Complex.I / ↑n)
hζ : IsPrimitiveRoot ζ n
hex : ∃ ζ' ∈ primitiveRoots n ℂ, ‖↑q - ζ'‖ < q + 1
this✝ : ¬eval (↑q) (cyclotomic n ℂ) = 0
x : ℂ
hx : x ∈ primitiveRoots n ℂ
this : ‖↑q - x‖ ≤ q + 1
⊢ ‖↑q - x‖ ≤ ↑(q + 1).toNNReal

Proof state:
n : ℕ
q : ℝ
hn' : 3 ≤ n
hq' : 1 < q
hn : 0 < n
hq : 0 < q
hfor : ∀ ζ' ∈ primitiveRoots n ℂ, ‖↑q - ζ'‖ ≤ q + 1
ζ : ℂ := Complex.exp (2 * ↑Real.pi * Complex.I / ↑n)
hζ : IsPrimitiveRoot ζ n
this : ¬SameRay ℝ (↑q) (-ζ)
⊢ ‖↑q - ζ‖ < q + 1

Tactic:
convert norm_add_lt_of_not_sameRay this using 2

Result:
case h.e'_4.h.e'_5
n : ℕ
q : ℝ
hn' : 3 ≤ n
hq' : 1 < q
hn : 0 < n
hq : 0 < q
hfor : ∀ ζ' ∈ primitiveRoots n ℂ, ‖↑q - ζ'‖ ≤ q + 1
ζ : ℂ := Complex.exp (2 * ↑Real.pi * Complex.I / ↑n)
hζ : IsPrimitiveRoot ζ n
this : ¬SameRay ℝ (↑q) (-ζ)
⊢ q = ‖↑q‖

case h.e'_4.h.e'_6
n : ℕ
q : ℝ
hn' : 3 ≤ n
hq' : 1 < q
hn : 0 < n
hq : 0 < q
hfor : ∀ ζ' ∈ primitiveRoots n ℂ, ‖↑q - ζ'‖ ≤ q + 1
ζ : ℂ := Complex.exp (2 * ↑Real.pi * Complex.I / ↑n)
hζ : IsPrimitiveRoot ζ n
this : ¬SameRay ℝ (↑q) (-ζ)
⊢ 1 = ‖-ζ‖

Proof state:
case h.e'_4.h.e'_6
n : ℕ
q : ℝ
hn' : 3 ≤ n
hq' : 1 < q
hn : 0 < n
hq : 0 < q
ζ' : ℂ
hζ' : IsPrimitiveRoot ζ' n
⊢ 1 = ‖ζ'‖

Tactic:
rw [hζ'.norm'_eq_one hn.ne']

Result:
no goals

Proof state:
n : ℕ
q : ℝ
hn' : 3 ≤ n
hq' : 1 < q
hn : 0 < n
hq : 0 < q
hfor : ∀ ζ' ∈ primitiveRoots n ℂ, ‖↑q - ζ'‖ ≤ q + 1
ζ : ℂ := Complex.exp (2 * ↑Real.pi * Complex.I / ↑n)
hζ : IsPrimitiveRoot ζ n
⊢ ¬(-ζ).arg = 0

Tactic:
intro h

Result:
n : ℕ
q : ℝ
hn' : 3 ≤ n
hq' : 1 < q
hn : 0 < n
hq : 0 < q
hfor : ∀ ζ' ∈ primitiveRoots n ℂ, ‖↑q - ζ'‖ ≤ q + 1
ζ : ℂ := Complex.exp (2 * ↑Real.pi * Complex.I / ↑n)
hζ : IsPrimitiveRoot ζ n
h : (-ζ).arg = 0
⊢ False

Proof state:
n : ℕ
q : ℝ
hn' : 3 ≤ n
hq' : 1 < q
hn : 0 < n
hq : 0 < q
hfor : ∀ ζ' ∈ primitiveRoots n ℂ, ‖↑q - ζ'‖ ≤ q + 1
ζ : ℂ := Complex.exp (2 * ↑Real.pi * Complex.I / ↑n)
hζ : IsPrimitiveRoot ζ n
hex : ∃ ζ' ∈ primitiveRoots n ℂ, ‖↑q - ζ'‖ < q + 1
⊢ eval q (cyclotomic n ℝ) < (q + 1) ^ φ n

Tactic:
have : ¬eval (↑q) (cyclotomic n ℂ) = 0 := by simpa using (cyclotomic_pos' n hq').ne.symm

Result:
n : ℕ
q : ℝ
hn' : 3 ≤ n
hq' : 1 < q
hn : 0 < n
hq : 0 < q
hfor : ∀ ζ' ∈ primitiveRoots n ℂ, ‖↑q - ζ'‖ ≤ q + 1
ζ : ℂ := Complex.exp (2 * ↑Real.pi * Complex.I / ↑n)
hζ : IsPrimitiveRoot ζ n
hex : ∃ ζ' ∈ primitiveRoots n ℂ, ‖↑q - ζ'‖ < q + 1
this : ¬eval (↑q) (cyclotomic n ℂ) = 0
⊢ eval q (cyclotomic n ℝ) < (q + 1) ^ φ n

Proof state:
case refine_2
n : ℕ
q : ℝ
hn' : 3 ≤ n
hq' : 1 < q
hn : 0 < n
hq : 0 < q
hfor : ∀ ζ' ∈ primitiveRoots n ℂ, ‖↑q - ζ'‖ ≤ q + 1
ζ : ℂ := Complex.exp (2 * ↑Real.pi * Complex.I / ↑n)
hζ : IsPrimitiveRoot ζ n
h : ζ.re ≤ 0 ∧ ζ.im = 0
hζ₀ : ζ ≠ 0
this : ζ = -1
⊢ False

Tactic:
rw [this] at hζ

Result:
case refine_2
n : ℕ
q : ℝ
hn' : 3 ≤ n
hq' : 1 < q
hn : 0 < n
hq : 0 < q
hfor : ∀ ζ' ∈ primitiveRoots n ℂ, ‖↑q - ζ'‖ ≤ q + 1
ζ : ℂ := Complex.exp (2 * ↑Real.pi * Complex.I / ↑n)
hζ : IsPrimitiveRoot (-1) n
h : ζ.re ≤ 0 ∧ ζ.im = 0
hζ₀ : ζ ≠ 0
this : ζ = -1
⊢ False

Proof state:
n : ℕ
q : ℝ
hn' : 3 ≤ n
hq' : 1 < q
hn : 0 < n
hq : 0 < q
hfor : ∀ ζ' ∈ primitiveRoots n ℂ, ‖↑q - ζ'‖ ≤ q + 1
ζ : ℂ := Complex.exp (2 * ↑Real.pi * Complex.I / ↑n)
⊢ eval q (cyclotomic n ℝ) < (q + 1) ^ φ n

Tactic:
have hζ : IsPrimitiveRoot ζ n := Complex.isPrimitiveRoot_exp n hn.ne'

Result:
n : ℕ
q : ℝ
hn' : 3 ≤ n
hq' : 1 < q
hn : 0 < n
hq : 0 < q
hfor : ∀ ζ' ∈ primitiveRoots n ℂ, ‖↑q - ζ'‖ ≤ q + 1
ζ : ℂ := Complex.exp (2 * ↑Real.pi * Complex.I / ↑n)
hζ : IsPrimitiveRoot ζ n
⊢ eval q (cyclotomic n ℝ) < (q + 1) ^ φ n

Proof state:
n : ℕ
q : ℝ
hn' : 3 ≤ n
hq' : 1 < q
hn : 0 < n
⊢ eval q (cyclotomic n ℝ) < (q + 1) ^ φ n

Tactic:
have hq := zero_lt_one.trans hq'

Result:
n : ℕ
q : ℝ
hn' : 3 ≤ n
hq' : 1 < q
hn : 0 < n
hq : 0 < q
⊢ eval q (cyclotomic n ℝ) < (q + 1) ^ φ n

Proof state:
case convert_6.intro.intro
n : ℕ
q : ℝ
hn' : 3 ≤ n
hq' : 1 < q
hn : 0 < n
hq : 0 < q
hfor : ∀ ζ' ∈ primitiveRoots n ℂ, ‖↑q - ζ'‖ ≤ q + 1
ζ✝ : ℂ := Complex.exp (2 * ↑Real.pi * Complex.I / ↑n)
hζ✝ : IsPrimitiveRoot ζ✝ n
this : ¬eval (↑q) (cyclotomic n ℂ) = 0
ζ : ℂ
hζ : ζ ∈ primitiveRoots n ℂ
hhζ : ‖↑q - ζ‖ < q + 1
⊢ ∃ a, ∃ (_ : a ∈ primitiveRoots n ℂ), True ∧ ‖↑q - a‖ < ↑(q + 1).toNNReal

Tactic:
exact ⟨ζ, hζ, by simp [hhζ]⟩

Result:
no goals

Proof state:
case refine_1
n : ℕ
q : ℝ
hn' : 3 ≤ n
hq' : 1 < q
hn : 0 < n
hq : 0 < q
hfor : ∀ ζ' ∈ primitiveRoots n ℂ, ‖↑q - ζ'‖ ≤ q + 1
ζ : ℂ := Complex.exp (2 * ↑Real.pi * Complex.I / ↑n)
hζ : IsPrimitiveRoot ζ n
h : ζ.re ≤ 0 ∧ ζ.im = 0
hζ₀ : ζ ≠ 0
⊢ ζ.re ≠ 0

Tactic:
contrapose! hζ₀

Result:
case refine_1
n : ℕ
q : ℝ
hn' : 3 ≤ n
hq' : 1 < q
hn : 0 < n
hq : 0 < q
hfor : ∀ ζ' ∈ primitiveRoots n ℂ, ‖↑q - ζ'‖ ≤ q + 1
ζ : ℂ := Complex.exp (2 * ↑Real.pi * Complex.I / ↑n)
hζ : IsPrimitiveRoot ζ n
h : ζ.re ≤ 0 ∧ ζ.im = 0
hζ₀ : ζ.re = 0
⊢ ζ = 0

Proof state:
n : ℕ
q : ℝ
hn' : 3 ≤ n
hq' : 1 < q
hn : 0 < n
hq : 0 < q
hfor : ∀ ζ' ∈ primitiveRoots n ℂ, ‖↑q - ζ'‖ ≤ q + 1
ζ : ℂ := Complex.exp (2 * ↑Real.pi * Complex.I / ↑n)
hζ : IsPrimitiveRoot ζ n
⊢ ∃ ζ' ∈ primitiveRoots n ℂ, ‖↑q - ζ'‖ < q + 1

Tactic:
refine ⟨ζ, (mem_primitiveRoots hn).mpr hζ, ?_⟩

Result:
n : ℕ
q : ℝ
hn' : 3 ≤ n
hq' : 1 < q
hn : 0 < n
hq : 0 < q
hfor : ∀ ζ' ∈ primitiveRoots n ℂ, ‖↑q - ζ'‖ ≤ q + 1
ζ : ℂ := Complex.exp (2 * ↑Real.pi * Complex.I / ↑n)
hζ : IsPrimitiveRoot ζ n
⊢ ‖↑q - ζ‖ < q + 1