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LeanPool.Superdiffusion.Algsuperdiff.Section3.Provider.Diffusivity.ApproximateRecurrence.Closure.Step5InputShellMoment

Step5InputShellMoment #

Ported from scottnarmstrong/Superdiffusion at 7f20476385d4af418f110303085ad0740c9eba46. Module imports, support namespace and local option directives adapted for Lean Pool.

hshell: the grid fourth moment of the averaged fresh shell #

Closure.Step5Basket.step5GaugeEndpoint_closureFamilies_of_momentLegs leaves hshell as the binder

  ( avsum_{R in grid}  E[ |(k_{n+h} - k_n)_R|^4 ] )^{1/2}
      <=  C1 * h * 3^{2 cgamma (n+h)} ,

the grid being descendantsAtDepth cu_K j at K - j = nmesh <= n and |.| the exact Euclidean matrix operator norm. This module proves it.

The route #

The cube R has scale nmesh <= n, so cu_R sits inside the window z_R + cu_n based at the cube's own site z_R = triadicCubeShift R. On that window ABK26's e.km.kn.Linfty.smallcube gives the deterministic domination |k_{n+h} - k_n|(x) <= translatedIncrementSupBound z_R n (n+h), so the cube average of each entry is dominated by the same random variable, and

  |(k_{n+h} - k_n)_R|  <=  d^2 * translatedIncrementSupBound z_R n (n+h) .

The probabilistic half is the proved weak-Orlicz tail Provider.Stream.isBigOWith_gammaSigma_translatedIncrementSupBound_cutoffLaw, whose amplitude is uniform in the base point; CoarseGraining's layer-cake moment bound at p = 4, sigma = 2 turns it into a per-cube fourth moment <= (C_d sqrt h 3^{cgamma (n+h)})^4, and a uniform per-cube bound passes to the grid average by gridFourthMoment_le_of_forall_le. Taking the square root gives the display with C1 = step5ShellMomentConst d.

Nothing here is asymptotic in K: the per-cube bound does not see the localization scale at all.

References #

The cube average against a uniform bound on the open cube #

The cube average of an integrable scalar is dominated by a bound assumed on the open cube alone: the closed and open forms of a triadic cube differ by a null set.

The deterministic per-cube domination #

The averaged fresh shell is dominated by the small-cube L^infty bound at the cube's own site. For a cube of scale at most n the entries of k_{n+h} - k_n are dominated on cu_R by translatedIncrementSupBound z_R, and the exact Euclidean operator norm is at most the entrywise l^1 sum.

The per-cube fourth moment #

The absolute dimensional constant of hshell: the entrywise-l^1 comparison d^2 of the Euclidean operator norm, times CoarseGraining's layer-cake moment constant at p = 4, sigma = 2, times the small-cube L^infty constant of e.km.kn.Linfty.smallcube, squared.

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    The constant of hshell.

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      The weak-Orlicz tail of the averaged fresh shell, at the amplitude of e.km.kn.Linfty.smallcube and the entrywise constant d^2. The proved tail is uniform in the base point, so this bound does not see the cube.

      hshell on the closure's grid #

      hshell, proved. The square root of the grid fourth moment of the averaged fresh shell is at most h 3^{2 cgamma (n+h)}, at the explicit absolute constant = step5ShellMomentConst d.

      This is e.km.kn.Lp in the shape the Hoelder step consumes it, read on the closure's own grid descendantsAtDepth cu_K j at K - j = nmesh <= n. The bound is uniform in the localization scale K.

      hAmem: the L^4 sample membership of the averaged fresh shell #

      hAmem, proved. The averaged fresh shell is L^4 in the sample: its weak-Orlicz tail is Gamma_2, and CoarseGraining's layer-cake integrability at p = 4 turns that into the fourth-power integrability.