AlexKontorovich/PrimeNumberTheoremAnd
Source indexedtheorem · leanprover/lean4:v4.32.0
Complex.Hadamard.EntireOfOrderAtMost.comp_add_const
PrimeNumberTheoremAnd.Mathlib.Analysis.Complex.HadamardFactorization.Order · PrimeNumberTheoremAnd/Mathlib/Analysis/Complex/HadamardFactorization/Order.lean:119 to 150
Source documentation
Finite order is invariant under translation of the input.
Exact Lean statement
theorem comp_add_const {ρ : ℝ} {f : ℂ → ℂ} (h : EntireOfOrderAtMost ρ f)
(hρ : 0 ≤ ρ) (c : ℂ) :
EntireOfOrderAtMost ρ (fun z : ℂ => f (z + c))Complete declaration
Lean source
Full Lean sourceLean 4
theorem comp_add_const {ρ : ℝ} {f : ℂ → ℂ} (h : EntireOfOrderAtMost ρ f) (hρ : 0 ≤ ρ) (c : ℂ) : EntireOfOrderAtMost ρ (fun z : ℂ => f (z + c)) := by refine ⟨h.differentiable.comp (differentiable_id.add (differentiable_const c)), ?_⟩ intro ε hε rcases h.exists_bound hε with ⟨C, hC, hCbound⟩ let A : ℝ := 1 + ‖c‖ let C' : ℝ := C * A ^ (ρ + ε) have hApos : 0 < A := by dsimp [A] positivity have hτnonneg : 0 ≤ ρ + ε := by linarith refine ⟨C', mul_pos hC (Real.rpow_pos_of_pos hApos _), ?_⟩ intro z have hbase : 1 + ‖z + c‖ ≤ A * (1 + ‖z‖) := by dsimp [A] have hnorm : ‖z + c‖ ≤ ‖z‖ + ‖c‖ := norm_add_le z c nlinarith [norm_nonneg z, norm_nonneg c] have hpow : (1 + ‖z + c‖) ^ (ρ + ε) ≤ (A * (1 + ‖z‖)) ^ (ρ + ε) := by exact Real.rpow_le_rpow (by positivity) hbase hτnonneg calc ‖f (z + c)‖ ≤ Real.exp (C * (1 + ‖z + c‖) ^ (ρ + ε)) := hCbound (z + c) _ ≤ Real.exp (C' * (1 + ‖z‖) ^ (ρ + ε)) := by refine Real.exp_le_exp.2 ?_ calc C * (1 + ‖z + c‖) ^ (ρ + ε) ≤ C * (A * (1 + ‖z‖)) ^ (ρ + ε) := by exact mul_le_mul_of_nonneg_left hpow hC.le _ = C' * (1 + ‖z‖) ^ (ρ + ε) := by rw [Real.mul_rpow (le_of_lt hApos) (by positivity : 0 ≤ 1 + ‖z‖)] ring