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LeanPool.Superdiffusion.Algsuperdiff.Section4.Provider.Homogenization.HomStepFourEnergy

HomStepFourEnergy #

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

Theorem B, §4.5, Step 4: the introduction's energy display #

The assembly #

  |⨍ ν|∇u|² - ⨍ σ_m|∇v|²|
      = |⨍ (a_L∇u - σ_m∇v)·∇v  +  σ_m ⨍ (∇u-∇v)·∇v|            (§3)
      ≤ (W_flux + σ_m W_grad) · ‖∇v‖_{W^{s,∞}}                   (§4)
      ≤ (3^{ms}σ_m C E D + σ_m 3^{ms} C E D) · C_sch 3^{-ms} D
      = 2 C C_sch E · σ_m D²  =  2 C C_sch E · bracket²,          (§5)

the last step being the EXACT identity σ D² = bracket² (sigma_mul_sq_dataBracket), where D is the un-square-rooted data bracket of the introduction's homogenization estimate and bracket the square-rooted one of the introduction's energy display. No inequality is spent there: the two printed brackets differ by exactly one factor √σ_m.

The three inputs, and which of them is a hypothesis #

1. Linearity of the volume average #

2. The ν-drop at the volume average #

⨍ ν|∇u|² = ⨍ ∇u·a∇u (a correction to the printed statement), pointwise and hence at the average. ν is not divided by anything and no ellipticity is used.

3. The energy split #

theorem Algsuperdiff.Section4.Provider.Homogenization.energy_split {d : ℕ} {A : HCPolySupport.CoeffField d} {Qc : HCPolySupport.TriadicCube d} {sigma nu : ℝ} {u v h : HCPolySupport.H1Function (HCPolySupport.openCubeSet Qc)} {g F : HCPolySupport.Vec d → HCPolySupport.Vec d} (hF : ∀ (x : HCPolySupport.Vec d), F x = HCPolySupport.matVecMul (A x) (u.grad x)) (hsym : ∀ (x : HCPolySupport.Vec d), HCPolySupport.symmPart (A x) = nu • 1) (hu : Support.IsDivFormWeakSolutionOn A (HCPolySupport.openCubeSet Qc) u g) (hv : Support.IsDivFormWeakSolutionOn (fun (x : HCPolySupport.Vec d) => sigma • 1) (HCPolySupport.openCubeSet Qc) v g) (hbu : Support.HasZeroTraceDifferenceOn (HCPolySupport.openCubeSet Qc) u h) (hbv : Support.HasZeroTraceDifferenceOn (HCPolySupport.openCubeSet Qc) v h) (hiU : MeasureTheory.IntegrableOn (fun (x : HCPolySupport.Vec d) => HCPolySupport.vecDot (u.grad x) (F x)) (HCPolySupport.openCubeSet Qc) MeasureTheory.volume) (hiV : MeasureTheory.IntegrableOn (fun (x : HCPolySupport.Vec d) => HCPolySupport.vecDot (v.grad x) (sigma • v.grad x)) (HCPolySupport.openCubeSet Qc) MeasureTheory.volume) (hiC : MeasureTheory.IntegrableOn (fun (x : HCPolySupport.Vec d) => HCPolySupport.vecDot (F x) (v.grad x)) (HCPolySupport.openCubeSet Qc) MeasureTheory.volume) :

The Step-4 energy split.

The pointwise identity of HomStepFourIdentity averaged, with the testing identity substituted into the second summand:

  ⨍ ν|∇u|² - ⨍ σ|∇v|²
      = ⨍ (a_L∇u - σ∇v)·∇v  +  σ ⨍ (∇u - ∇v)·∇v.

Both summands are cubePairings against the SAME test field ∇v, which is what the two duality bounds consume. The three integrability hypotheses are the manuscript's own u, v ∈ H¹(□_m) in force; they are stated rather than smuggled.

4. The duality step #

theorem Algsuperdiff.Section4.Provider.Homogenization.abs_energy_le_of_weakNegDual {d : ℕ} {Qc : HCPolySupport.TriadicCube d} {s sigma Wf Wg Ksup KHol : ℝ} {Fflux Fgrad gradv : HCPolySupport.Vec d → HCPolySupport.Vec d} {E : ℝ} (hsplit : E = cubePairing Qc Fflux gradv + sigma * cubePairing Qc Fgrad gradv) (hsigma : 0 ≤ sigma) (hsup : 0 ≤ Ksup) (hhol : 0 ≤ KHol) (hb : ∀ x ∈ HCPolySupport.openCubeSet Qc, ‖gradv x‖ ≤ Ksup) (hH : Support.HolderSeminormBoundOn (HCPolySupport.openCubeSet Qc) s KHol gradv) (hWf : WeakNegDualBoundOn Qc s Wf Fflux) (hWg : WeakNegDualBoundOn Qc s Wg Fgrad) :
|E| ≤ (Wf + sigma * Wg) * wsInftyGauge Qc s Ksup KHol

The two pairings, applied. From the split and the two duality levels, the energy difference is bounded by (W_flux + σ W_grad) times the test gauge of ∇v.

5. The bracket arithmetic σ D² = bracket² #

noncomputable def Algsuperdiff.Section4.Provider.Homogenization.dataBracket (sigma pow Kg KhInf Kh : ℝ) :

The un-square-rooted data bracket of the introduction's homogenization estimate.

Equations
Instances For
    noncomputable def Algsuperdiff.Section4.Provider.Homogenization.energyBracket (sigma pow Kg KhInf Kh : ℝ) :

    The square-rooted data bracket of the introduction's energy display.

    Equations
    Instances For
      theorem Algsuperdiff.Section4.Provider.Homogenization.sqrt_mul_dataBracket (sigma pow Kg KhInf Kh : ℝ) (hsig : 0 < sigma) :
      √sigma * dataBracket sigma pow Kg KhInf Kh = energyBracket sigma pow Kg KhInf Kh

      The exact relation between the two printed brackets: √σ · D = bracket.

      No inequality is spent: the introduction's energy display bracket is the the introduction's homogenization estimate bracket multiplied by √σ_m.

      theorem Algsuperdiff.Section4.Provider.Homogenization.sigma_mul_sq_dataBracket (sigma pow Kg KhInf Kh : ℝ) (hsig : 0 < sigma) :
      sigma * dataBracket sigma pow Kg KhInf Kh ^ 2 = energyBracket sigma pow Kg KhInf Kh ^ 2

      σ D² = bracket², the form the assembly consumes.

      6. The §4.5 display #

      theorem Algsuperdiff.Section4.Provider.Homogenization.stepFourEnergyDisplay {d : ℕ} {Qc : HCPolySupport.TriadicCube d} {s sigma pow Kg KhInf Kh Cw Csch EB Ksup KHol : ℝ} {Fflux Fgrad gradv : HCPolySupport.Vec d → HCPolySupport.Vec d} {E : ℝ} (hsig : 0 < sigma) (hCw : 0 ≤ Cw) (hEB : 0 ≤ EB) (hD : 0 ≤ dataBracket sigma pow Kg KhInf Kh) (hsup : 0 ≤ Ksup) (hhol : 0 ≤ KHol) (hsplit : E = cubePairing Qc Fflux gradv + sigma * cubePairing Qc Fgrad gradv) (hb : ∀ x ∈ HCPolySupport.openCubeSet Qc, ‖gradv x‖ ≤ Ksup) (hH : Support.HolderSeminormBoundOn (HCPolySupport.openCubeSet Qc) s KHol gradv) (hSch : wsInftyGauge Qc s Ksup KHol ≤ Csch * (Real.rpow 3 (s * ↑Qc.scale))⁻¹ * dataBracket sigma pow Kg KhInf Kh) (hWf : WeakNegDualBoundOn Qc s (Real.rpow 3 (s * ↑Qc.scale) * sigma * (Cw * EB * dataBracket sigma pow Kg KhInf Kh)) Fflux) (hWg : WeakNegDualBoundOn Qc s (Real.rpow 3 (s * ↑Qc.scale) * (Cw * EB * dataBracket sigma pow Kg KhInf Kh)) Fgrad) :
      |E| ≤ 2 * Cw * Csch * EB * energyBracket sigma pow Kg KhInf Kh ^ 2

      the introduction's energy display from the three §4.5 inputs.

      The weak flux bound at level 3^{ms} σ (C E D), the weak gradient bound at level 3^{ms} (C E D) — the two halves of the ONE coarse-graining application — and the Schauder gauge C_sch 3^{-ms} D (the Schauder gap) compose to

        |⨍ ν|∇u|² - ⨍ σ|∇v|²| ≤ 2 C C_sch E · σ D²  =  2 C C_sch E · bracket².
      

      Every constant is explicit; nothing is absorbed silently. The residual 2 C C_sch is exactly what's witness rescaling (ethmB_const_smul_moment) transports through the moment bound.