OAI/Analysis/LipschitzHilbert/Phase/PhaseCombinatorics.lean

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Finite-phase resonance combinatorics

These are the elementary finite combinatorial ingredients of §7, Lemma phase:quantile-gap, of A uniform Hilbert transform estimate for Lipschitz directions. The frequency separation is quantitative; no assumption about additive independence is made.

  1. def OAI.LipschitzHilbert.PhaseCombinatorics.Separated line 27
  2. def OAI.LipschitzHilbert.PhaseCombinatorics.Resonant line 30
  3. theorem OAI.LipschitzHilbert.PhaseCombinatorics.resonant_swap_left line 33
  4. theorem OAI.LipschitzHilbert.PhaseCombinatorics.resonant_swap_right line 37
  5. theorem OAI.LipschitzHilbert.PhaseCombinatorics.resonant_swap_pairs line 41
  6. theorem OAI.LipschitzHilbert.PhaseCombinatorics.unique_fourth line 49

    Source documentation

    Three fixed indices determine at most one fourth index.

    theorem unique_fourth {frequency : ι → ℝ} {gap : ℝ}
        (hgap : 0 < gap) (hsep : Separated frequency gap)
        {i j k l l' : ι} (h : Resonant frequency gap i j k l)
        (h' : Resonant frequency gap i j k l') : l = l' := by
    …

    Mentions: OAI.LipschitzHilbert.PhaseCombinatorics.Separated, OAI.LipschitzHilbert.PhaseCombinatorics.Resonant

  7. theorem OAI.LipschitzHilbert.PhaseCombinatorics.unique_third line 62
  8. theorem OAI.LipschitzHilbert.PhaseCombinatorics.unique_second line 68
  9. theorem OAI.LipschitzHilbert.PhaseCombinatorics.unique_first line 74
  10. theorem OAI.LipschitzHilbert.PhaseCombinatorics.sum_completions_le line 82

    Source documentation

    For three fixed indices, summing a nonnegative weight over resonant completions costs at most that weight.

    theorem sum_completions_le [Fintype ι] {frequency : ι → ℝ} {gap : ℝ}
        (hgap : 0 < gap) (hsep : Separated frequency gap)
        (i j k : ι) (a : ℝ) (ha : 0 ≤ a) :
        (∑ l, if Resonant frequency gap i j k l then a else 0) ≤ a := by
    …

    Mentions: OAI.LipschitzHilbert.PhaseCombinatorics.Separated, OAI.LipschitzHilbert.PhaseCombinatorics.Resonant

  11. theorem OAI.LipschitzHilbert.PhaseCombinatorics.resonance_triple_mass_le_one line 107

    Source documentation

    Each triple-coordinate marginal used in the fourth-moment argument has total mass at most one. This is the first marginal, omitting the fourth coordinate.

    theorem resonance_triple_mass_le_one [Fintype ι]
        {frequency : ι → ℝ} {gap : ℝ} (hgap : 0 < gap)
        (hsep : Separated frequency gap) (x : ι → ℝ)
        (hx : ∀ i, 0 ≤ x i) (hsum : ∑ i, x i = 1) :
        (∑ i, ∑ j, ∑ k, ∑ l,
          if Resonant frequency gap i j k l then x i * x j * x k else 0) ≤ 1 := by
    …

    Mentions: OAI.LipschitzHilbert.PhaseCombinatorics.Separated, OAI.LipschitzHilbert.PhaseCombinatorics.Resonant

  12. abbrev OAI.LipschitzHilbert.PhaseCombinatorics.Quadruple line 128
  13. def OAI.LipschitzHilbert.PhaseCombinatorics.swapPairs line 130
  14. def OAI.LipschitzHilbert.PhaseCombinatorics.swapLast line 136
  15. def OAI.LipschitzHilbert.PhaseCombinatorics.marginal line 143

    Source documentation

    The first of the four triple-coordinate subprobability weights.

    def marginal (frequency : ι → ℝ) (gap : ℝ) (x : ι → ℝ) (q : Quadruple ι) : ℝ :=
    …

    Mentions: OAI.LipschitzHilbert.PhaseCombinatorics.Quadruple

  16. theorem OAI.LipschitzHilbert.PhaseCombinatorics.marginal_nonneg line 147
  17. theorem OAI.LipschitzHilbert.PhaseCombinatorics.marginal_mass_le_one line 154
  18. theorem OAI.LipschitzHilbert.PhaseCombinatorics.permuted_marginal_mass_le_one line 163

    Source documentation

    Reindexing gives all four subprobability bounds without further losses.

    theorem permuted_marginal_mass_le_one [Fintype ι]
        {frequency : ι → ℝ} {gap : ℝ} (hgap : 0 < gap)
        (hsep : Separated frequency gap) (x : ι → ℝ)
        (hx : ∀ i, 0 ≤ x i) (hsum : ∑ i, x i = 1)
        (e : Quadruple ι ≃ Quadruple ι) :
        (∑ q : Quadruple ι, marginal frequency gap x (e q)) ≤ 1 := by
    …

    Mentions: OAI.LipschitzHilbert.PhaseCombinatorics.Separated, OAI.LipschitzHilbert.PhaseCombinatorics.Quadruple, OAI.LipschitzHilbert.PhaseCombinatorics.marginal

  19. theorem OAI.LipschitzHilbert.PhaseCombinatorics.affinity_le_one line 173

    Source documentation

    The elementary affinity bound for two subprobabilities.

    theorem affinity_le_one [Fintype ι] (a b : ι → ℝ)
        (ha : ∀ i, 0 ≤ a i) (hb : ∀ i, 0 ≤ b i)
        (hsa : ∑ i, a i ≤ 1) (hsb : ∑ i, b i ≤ 1) :
        (∑ i, Real.sqrt (a i * b i)) ≤ 1 := by
    …
  20. theorem OAI.LipschitzHilbert.PhaseCombinatorics.geometric_sum_sq_le_affinity line 192

    Source documentation

    Four-factor Hölder in the form used by the quantile argument: the square of the geometric sum is bounded by the affinity of its first two weights.

    theorem geometric_sum_sq_le_affinity [Fintype ι] (a b c d : ι → ℝ)
        (hc : ∀ i, 0 ≤ c i) (hd : ∀ i, 0 ≤ d i)
        (hsc : ∑ i, c i ≤ 1) (hsd : ∑ i, d i ≤ 1) :
        (∑ i, Real.sqrt (Real.sqrt (a i * b i) * Real.sqrt (c i * d i))) ^ 2 ≤
          ∑ i, Real.sqrt (a i * b i) := by
    …
  21. def OAI.LipschitzHilbert.PhaseCombinatorics.geometricTerm line 222
  22. theorem OAI.LipschitzHilbert.PhaseCombinatorics.geometricTerm_eq line 231

    Source documentation

    The four triple-coordinate weights have geometric mean (xᵢ xⱼ xₖ xₗ)^(3/4), written with square roots.

    theorem geometricTerm_eq {frequency : ι → ℝ} {gap : ℝ} {x : ι → ℝ}
        (hx : ∀ i, 0 ≤ x i) (i j k l : ι) :
        geometricTerm frequency gap x (i, j, k, l) =
          if Resonant frequency gap i j k l then
            Real.sqrt (Real.sqrt ((x i * x j * x k * x l) ^ 3)) else 0 := by
    …

    Mentions: OAI.LipschitzHilbert.PhaseCombinatorics.geometricTerm, OAI.LipschitzHilbert.PhaseCombinatorics.Resonant

  23. theorem OAI.LipschitzHilbert.PhaseCombinatorics.sqrt_sqrt_cube_eq_rpow line 251
  24. theorem OAI.LipschitzHilbert.PhaseCombinatorics.geometricTerm_eq_rpow line 257
  25. def OAI.LipschitzHilbert.PhaseCombinatorics.resonanceSum line 268

    Source documentation

    The ordinary fourth-moment quantity in the manuscript.

    def resonanceSum [Fintype ι] (frequency : ι → ℝ) (gap : ℝ) (x : ι → ℝ) : ℝ :=
    …
  26. theorem OAI.LipschitzHilbert.PhaseCombinatorics.resonanceSum_sq_le_affinity line 272

    Source documentation

    The affinity inequality that precedes the strict quantile deficit.

    theorem resonanceSum_sq_le_affinity [Fintype ι]
        {frequency : ι → ℝ} {gap : ℝ} (hgap : 0 < gap)
        (hsep : Separated frequency gap) (x : ι → ℝ)
        (hx : ∀ i, 0 ≤ x i) (hsum : ∑ i, x i = 1) :
        resonanceSum frequency gap x ^ 2 ≤
          ∑ q : Quadruple ι, Real.sqrt
            (marginal frequency gap x q * marginal frequency gap x (swapPairs q)) := by
    …

    Mentions: OAI.LipschitzHilbert.PhaseCombinatorics.Separated, OAI.LipschitzHilbert.PhaseCombinatorics.resonanceSum, OAI.LipschitzHilbert.PhaseCombinatorics.Quadruple, OAI.LipschitzHilbert.PhaseCombinatorics.marginal, OAI.LipschitzHilbert.PhaseCombinatorics.swapPairs

  27. theorem OAI.LipschitzHilbert.PhaseCombinatorics.resonanceSum_le_one line 286

    Source documentation

    The usual constant-one fourth-moment bound, before its strict improvement.

    theorem resonanceSum_le_one [Fintype ι]
        {frequency : ι → ℝ} {gap : ℝ} (hgap : 0 < gap)
        (hsep : Separated frequency gap) (x : ι → ℝ)
        (hx : ∀ i, 0 ≤ x i) (hsum : ∑ i, x i = 1) :
        resonanceSum frequency gap x ≤ 1 := by
    …

    Mentions: OAI.LipschitzHilbert.PhaseCombinatorics.Separated, OAI.LipschitzHilbert.PhaseCombinatorics.resonanceSum