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Project-declaredLean 4.31.0 · mathlib@fabf563a7c95

Res To Imag Axis Real re mul eq

ResToImagAxis.Real.re_mul_eq

Plain-language statement

Real part of a product on the imaginary axis is the product of real parts, when both factors are real-valued there.

Exact Lean statement

theorem ResToImagAxis.Real.re_mul_eq {F G : ℍ → ℂ} (hF : ResToImagAxis.Real F)
    (hG : ResToImagAxis.Real G) (t : ℝ) :
    ((F * G).resToImagAxis t).re = (F.resToImagAxis t).re * (G.resToImagAxis t).re

Formal artifact

Lean source

Canonical source
Full Lean sourceLean 4
theorem ResToImagAxis.Real.re_mul_eq {F G : ℍ  ℂ} (hF : ResToImagAxis.Real F)    (hG : ResToImagAxis.Real G) (t : ) :    ((F * G).resToImagAxis t).re = (F.resToImagAxis t).re * (G.resToImagAxis t).re := by  simp only [Function.resToImagAxis, ResToImagAxis]  split_ifs with ht  · have hFreal := hF t ht    have hGreal := hG t ht    simp only [Function.resToImagAxis, ResToImagAxis, ht, ↓reduceDIte] at hFreal hGreal    simp [Pi.mul_apply, Complex.mul_re, hFreal, hGreal]  · simp
Project
Sphere Packing in Dimension 8
License
Apache-2.0
Commit
acfc6204e65a
Source
SpherePacking/ModularForms/ResToImagAxis.lean:215-224

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Related declarations

Project-declaredLean 4.31.0

Anti Der Pos

antiDerPos

Plain-language statement

If FF is a modular form where F(it)F(it) is positive for sufficiently large tt (i.e. constant term is positive) and the derivative is positive, then FF is also positive.

sphere packingFourier analysismodular forms

Source project: Sphere Packing in Dimension 8

Person-level attribution pending.

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Project-declaredLean 4.31.0

Anti Serre Der Pos

antiSerreDerPos

Plain-language statement

Let F:HCF : \mathbb{H} \to \mathbb{C} be a holomorphic function where F(it)F(it) is real for all t>0t > 0. Assume that Serre derivative kF\partial_k F is positive on the imaginary axis. If F(it)F(it) is positive for sufficiently large tt, then F(it)F(it) is positive for all t>0t > 0.

sphere packingFourier analysismodular forms

Source project: Sphere Packing in Dimension 8

Person-level attribution pending.

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