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LeanPool.Superdiffusion.Algsuperdiff.Section4.Provider.ExcessDecay.ResidueBudget

ResidueBudget #

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

The residue budget form of the boundary scalar, and the sharpening record #

What is proved #

Two consequences of ResidueInterface.exists_scalarControl_boundaryBranch_ comparator.

Why the interface was moved #

The gradient residue 3^n·Σᵢ‖∂ᵢu‖_{L²(K')} has exactly two known producers and both are blocked:

The second producer does not price the gradient at all; it prices ‖u − w‖_{L²(K')}. Moving the interface to ‖u − w‖ is therefore what makes that producer even expressible. Its arithmetic is measured in ResidueAbsorption.lean.

References #

The sum of coordinate L² norms is bounded by dimension times the vector L² norm.

theorem Algsuperdiff.Section4.Provider.ExcessDecay.error_pin_of_successor_constant {A E s : ℝ} (hE : 0 ≤ E) (hpin : (A + 1) * E ≤ s ^ 4) :
A * E ≤ s ^ 4

A pin at the successor constant implies the source pin.

1. The ∀-budget form #

theorem Algsuperdiff.Section4.Provider.ExcessDecay.exists_scalarControl_of_boundaryBranch_harmonicResidue (d : ℕ) [NeZero d] :
∃ (C : ℝ), 0 ≤ C ∧ ∀ {n m : ℤ} {x z : HCPolySupport.Vec d} {i : Fin d} {σ : ℝ}, n + 2 ≤ m → x ∈ HCPolySupport.openCubeSet (HCPolySupport.originCube d m) → z ∈ HCPolySupport.openCubeSet (HCPolySupport.originCube d m) → (fun (y : HCPolySupport.Vec d) => x + y) '' HCPolySupport.openCubeSet (HCPolySupport.originCube d n) ⊆ (fun (y : HCPolySupport.Vec d) => z + y) '' HCPolySupport.openCubeSet (HCPolySupport.originCube d (n + 1)) ∩ HCPolySupport.openCubeSet (HCPolySupport.originCube d m) → σ = 1 ∨ σ = -1 → wellPlacedHalfGap m (n + 2) < σ * z i → ∀ (u h : HCPolySupport.H1Function (HCPolySupport.openCubeSet (HCPolySupport.originCube d m))), Support.HasZeroTraceDifferenceOn (HCPolySupport.openCubeSet (HCPolySupport.originCube d m)) u h → ∀ (R : ℝ), (∀ (w : HCPolySupport.H1Function (HCPolySupport.translateSet (flushSubCentre z m n i σ) (HCPolySupport.openCubeSet (HCPolySupport.originCube d n)))) (rho : HCPolySupport.H10Function (HCPolySupport.translateSet (flushSubCentre z m n i σ) (HCPolySupport.openCubeSet (HCPolySupport.originCube d n)))), Support.IsWeaklyHarmonicOn (HCPolySupport.translateSet (flushSubCentre z m n i σ) (HCPolySupport.openCubeSet (HCPolySupport.originCube d n))) w → (∀ (y : HCPolySupport.Vec d), w.toFun y = u.toFun y + rho.toFun y) → (∀ (y : HCPolySupport.Vec d), w.grad y = u.grad y + rho.grad y) → (Support.normalizedL2On ((fun (y : HCPolySupport.Vec d) => flushSubCentre z m n i σ + y) '' HCPolySupport.openCubeSet (HCPolySupport.originCube d n)) fun (y : HCPolySupport.Vec d) => u.toFun y - w.toFun y) ≤ R) → |HCPolySupport.volumeAverage ((fun (y : HCPolySupport.Vec d) => wellPlacedCentre x m (n + 2) + y) '' HCPolySupport.openCubeSet (HCPolySupport.originCube d (n + 2))) fun (y : HCPolySupport.Vec d) => u.toFun y - h.toFun y| ≤ C * ((MeasureTheory.eLpNorm (fun (y : HCPolySupport.Vec d) => u.toFun y - HCPolySupport.volumeAverage ((fun (y' : HCPolySupport.Vec d) => z + y') '' HCPolySupport.openCubeSet (HCPolySupport.originCube d (n + 3)) ∩ HCPolySupport.openCubeSet (HCPolySupport.originCube d m)) u.toFun) 2 (Support.normalizedVolumeMeasureOn ((fun (y' : HCPolySupport.Vec d) => z + y') '' HCPolySupport.openCubeSet (HCPolySupport.originCube d (n + 3)) ∩ HCPolySupport.openCubeSet (HCPolySupport.originCube d m)))).toReal + 3 ^ n * ∑ i' : Fin d, (MeasureTheory.eLpNorm (fun (y : HCPolySupport.Vec d) => h.grad y i') 2 (Support.normalizedVolumeMeasureOn ((fun (y' : HCPolySupport.Vec d) => z + y') '' HCPolySupport.openCubeSet (HCPolySupport.originCube d (n + 3)) ∩ HCPolySupport.openCubeSet (HCPolySupport.originCube d m)))).toReal + R)

The boundary scalar at an abstract residue budget.

R is any real dominating the harmonic-approximation error at the flush sub-cube K' for every Δ-harmonic comparator of u there.

2. The sharpening record: the proved gradient residue recovered #