AlexKontorovich/PrimeNumberTheoremAnd
Source indexedlemma · leanprover/lean4:v4.32.0
Complex.log_norm_weierstrassFactor_ge_neg_two_pow
PrimeNumberTheoremAnd.Mathlib.Analysis.Complex.WeierstrassFactor · PrimeNumberTheoremAnd/Mathlib/Analysis/Complex/WeierstrassFactor.lean:288 to 309
Mathematical statement
Exact Lean statement
lemma log_norm_weierstrassFactor_ge_neg_two_pow {m : ℕ} {z : ℂ} (hz : ‖z‖ ≤ (1 / 2 : ℝ)) :
(-2 : ℝ) * ‖z‖ ^ (m + 1) ≤ Real.log ‖weierstrassFactor m z‖Complete declaration
Lean source
Full Lean sourceLean 4
lemma log_norm_weierstrassFactor_ge_neg_two_pow {m : ℕ} {z : ℂ} (hz : ‖z‖ ≤ (1 / 2 : ℝ)) : (-2 : ℝ) * ‖z‖ ^ (m + 1) ≤ Real.log ‖weierstrassFactor m z‖ := by have hz_lt : ‖z‖ < (1 : ℝ) := lt_of_le_of_lt hz (by norm_num) have hz1 : z ≠ (1 : ℂ) := by intro h have : (1 : ℝ) ≤ (1 / 2 : ℝ) := by simpa [h] using hz norm_num at this have hEq : weierstrassFactor m z = Complex.exp (-logTail m z) := weierstrassFactor_eq_exp_neg_tail m hz_lt hz1 have hlog : Real.log ‖weierstrassFactor m z‖ = (-logTail m z).re := by simp [hEq, Complex.norm_exp, Real.log_exp] have hre : (-logTail m z).re ≥ -‖logTail m z‖ := by simpa [norm_neg] using Complex.neg_norm_le_re (-logTail m z) have htail := norm_logTail_le_two_mul_norm_pow hz_lt hz m have : (-logTail m z).re ≥ (-2 : ℝ) * ‖z‖ ^ (m + 1) := by calc (-logTail m z).re ≥ -‖logTail m z‖ := hre _ ≥ (-2 : ℝ) * ‖z‖ ^ (m + 1) := by nlinarith [htail] simpa [hlog, mul_assoc, mul_left_comm, mul_comm] using this