AlexKontorovich/PrimeNumberTheoremAnd
Source indexedlemma · leanprover/lean4:v4.32.0
summable_vonMangoldt_div_rpow
PrimeNumberTheoremAnd.Wiener · PrimeNumberTheoremAnd/Wiener.lean:3990 to 4010
Source documentation
The von Mangoldt function divided by n ^ s is summable for s > 1.
Exact Lean statement
lemma summable_vonMangoldt_div_rpow {s : ℝ} (hs : 1 < s) : Summable (fun n ↦ Λ n / n ^ s)Complete declaration
Lean source
Full Lean sourceLean 4
lemma summable_vonMangoldt_div_rpow {s : ℝ} (hs : 1 < s) : Summable (fun n ↦ Λ n / n ^ s) := by have h_log_bound : ∀ n : ℕ, (Λ n : ℝ) ≤ Real.log n := fun n ↦ vonMangoldt_le_log suffices h_log_sum : Summable fun n : ℕ ↦ Real.log n / (n : ℝ) ^ s by exact .of_nonneg_of_le (fun n ↦ div_nonneg vonMangoldt_nonneg (by positivity)) (fun n ↦ div_le_div_of_nonneg_right (h_log_bound n) (by positivity)) h_log_sum have h_log_le_n_eps : ∀ ε > 0, ∃ C > 0, ∀ n : ℕ, n ≥ 2 → Real.log n / (n : ℝ) ^ s ≤ C * (n : ℝ) ^ (ε - s) := by intro ε hε_pos obtain ⟨C, hC_pos, hC⟩ : ∃ C > 0, ∀ n : ℕ, n ≥ 2 → Real.log n ≤ C * (n : ℝ) ^ ε := by refine ⟨1 / ε, by positivity, fun n hn ↦ ?_⟩ have := log_le_sub_one_of_pos (by positivity : 0 < (n : ℝ) ^ ε) rw [log_rpow (by positivity)] at this nlinarith [rpow_pos_of_pos (by positivity : 0 < (n : ℝ)) ε, mul_div_cancel₀ 1 hε_pos.ne'] refine ⟨C, hC_pos, fun n hn ↦ ?_⟩ rw [rpow_sub (by positivity)] exact le_trans (div_le_div_of_nonneg_right (hC n hn) (by positivity)) (by rw [div_eq_mul_inv]; ring_nf; norm_num) obtain ⟨C, _, hC⟩ : ∃ C > 0, ∀ n : ℕ, n ≥ 2 → Real.log n / (n : ℝ) ^ s ≤ C * (n : ℝ) ^ ((s - 1) / 2 - s) := h_log_le_n_eps ((s - 1) / 2) (by linarith) rw [← summable_nat_add_iff 2] exact Summable.of_nonneg_of_le (fun n ↦ div_nonneg (log_nonneg (by norm_cast; omega)) (rpow_nonneg (by positivity) _)) (fun n ↦ hC _ (by omega)) (Summable.mul_left _ <| by simpa using summable_nat_add_iff 2 |>.2 <| summable_nat_rpow.2 <| by linarith)