OAI/Analysis/LipschitzHilbert/Fourier/SincMaskSchwartz.lean

GitHub source file

21 declarations, 0 contain sorry, 0 declared as axioms

Smooth sinc multipliers preserve Schwartz packets. The derivative bounds follow from the same compact cosine average used for the mask's Fourier support; no assertion about a singular quotient at zero is used.

  1. def OAI.LipschitzHilbert.sincJet line 17
  2. theorem OAI.LipschitzHilbert.sincJet_integrand_bound line 20
  3. theorem OAI.LipschitzHilbert.sincJet_integrable line 26
  4. theorem OAI.LipschitzHilbert.sincJet_bound line 35
  5. theorem OAI.LipschitzHilbert.sincJet_continuous line 43
  6. theorem OAI.LipschitzHilbert.sincJet_hasDerivAt line 53
  7. theorem OAI.LipschitzHilbert.sincJet_deriv line 83
  8. theorem OAI.LipschitzHilbert.sincJet_contDiff line 87
  9. theorem OAI.LipschitzHilbert.sincJet_zero line 99
  10. theorem OAI.LipschitzHilbert.sincJet_iteratedDeriv line 104
  11. theorem OAI.LipschitzHilbert.norm_iteratedDeriv_sinc_le_one line 110

    Source documentation

    All real sinc derivatives are uniformly bounded by one.

    theorem norm_iteratedDeriv_sinc_le_one (n : ℕ) (x : ℝ) :
        ‖iteratedDeriv n Real.sinc x‖ ≤ 1 := by
    …
  12. theorem OAI.LipschitzHilbert.sinc_hasTemperateGrowth line 115
  13. theorem OAI.LipschitzHilbert.affineSinc_hasTemperateGrowth line 122
  14. def OAI.LipschitzHilbert.affineSincSchwartz line 128

    Source documentation

    The genuine affine sinc multiplier applied to a Schwartz packet.

    def affineSincSchwartz (f : SchwartzMap ℝ ℂ) (a b : ℝ) : SchwartzMap ℝ ℂ :=
    …
  15. theorem OAI.LipschitzHilbert.affineSincSchwartz_apply line 131
  16. theorem OAI.LipschitzHilbert.sincProductAffine_hasTemperateGrowth line 135
  17. def OAI.LipschitzHilbert.sincProductSchwartz line 143

    Source documentation

    Multiplication by the actual even mask is a Schwartz operation.

    def sincProductSchwartz (f : SchwartzMap ℝ ℂ) (n : ℕ) (a b c d : ℝ) : SchwartzMap ℝ ℂ :=
    …
  18. theorem OAI.LipschitzHilbert.sincProductSchwartz_apply line 147
  19. theorem OAI.LipschitzHilbert.sincProductSchwartz_norm_le line 153
  20. theorem OAI.LipschitzHilbert.sincProductAffine_lipschitz line 160
  21. theorem OAI.LipschitzHilbert.sincProductSchwartz_deriv_le line 179

    Source documentation

    The extra derivative cost is precisely the sum of mask slopes.

    theorem sincProductSchwartz_deriv_le (f : SchwartzMap ℝ ℂ)
        (n : ℕ) (a b c d x : ℝ) :
        ‖deriv (sincProductSchwartz f n a b c d) x‖ ≤
          ‖deriv f x‖+(2*(n:ℝ)*(|a|+|c|))*‖f x‖ := by
    …

    Mentions: OAI.LipschitzHilbert.sincProductSchwartz