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LeanPool.Superdiffusion.Algsuperdiff.Section3.Provider.Affine.SuperposedDivergence

SuperposedDivergence #

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

∇·D̂_q at the superposed competitor (the G-leg of the superposed branch) #

CollarLayerEnvelopeG.lean builds the manuscript's antisymmetric matrix D̂_q (e.hatdq) and its cell divergence ∇·D̂_q(𝔰) at the single-mesh competitor family ℓ̂_p = competitorVertexData ℐ p. This module runs the same construction on the superposed family ℓ̂_p = ℓ_p + Σ_𝒞 (ℓ̂_p^𝒞 − ℓ_p), the second of the two admissible constructions, and provides the following local G-leg objects and estimates:

Why this module exists (finding M-1) #

The superposed branch of the Step-3 conclusion had used superposedCompetitorSlope … q — the gradient construction re-run at the load q — in its G leg. That is the wrong object: the manuscript's G leg is ∇·D̂_q, the divergence of the antisymmetric matrix built from the d basis members ℓ̂_{e_i}, not ∇ℓ̂_q. The two agree neither in law nor in shape, and the solenoidality binder stated at ∇ℓ̂_q is refutable. Everything below is stated at ∇·D̂_q; nothing below refers to, or corrects, the branch that used the gradient.

The object #

For the superposed family, e.hatdq reads entrywise

(D̂_q)_{ij} = (d − 1)⁻¹ ( q_j ℓ̂_{e_i} − q_i ℓ̂_{e_j} ) ,

which is superposedCompetitorAntisymEntry: competitorAntisymDatum's formula with the single-mesh vertex datum replaced by the superposed competitor, so only the d basis members occur, exactly as printed, and no linearity of p ↦ ℓ̂_p is assumed (e.hat.linear.linearity, is not used). superposedCompetitorAntisymEntry_antisymm is the antisymmetry.

At the manuscript's divergence convention (∇·A)_j = ∑_i ∂_{x_i} A_{ij} (the footnote) the j-th coordinate of ∇·D̂_q is the sum over i of the i-th coordinate of the gradient of the (i,j) entry. The superposed competitor carries a defined piecewise-constant gradient field superposedCompetitorSlope (there is no single mesh whose Kuhn-slope operator applies to the entry — that is exactly what denies), so superposedCompetitorDivergence is defined by that distributed expression:

(∇·D̂_q)(x)_j = ∑_i (d − 1)⁻¹ ( q_j (∇ℓ̂_{e_i})(x)_i − q_i (∇ℓ̂_{e_j})(x)_i ) .

Two theorems show that this is the proved single-mesh construction and not a new one: competitorDivergence_eq_sum_entrywise says the distributed expression at single-mesh Kuhn slopes IS CollarLayerEnvelopeG.competitorDivergence (it is kuhnSlope_competitorAntisymDatum, i.e. the unconditional linearity of kuhnSlope in its datum, re-summed), and globalCompetitorDivergence_eq_competitorDivergence says that at ONE component — where a single mesh does govern — the distributed expression evaluated on that component's own field is literally competitorDivergence at the root cell containing the point.

The normalization ∇·D_q = q #

superposedCompetitorCellDivergence_sub_eq is the exact algebraic identity

(∇·D̂_q)(𝔰)_j − q_j = (d−1)⁻¹ ( (∑_i (u_i)_i) q_j − ∑_i q_i (u_j)_i ) ,
u_i = ∇ℓ̂_{e_i}(𝔰) − e_i ,

the d of ∑_i (e_i)_i and the q_j of ∑_i q_i (e_j)_i cancelling against the (d−1) of e.dq — this is the display ∇·D_q = q in its cellwise form, and superposedCompetitorCellDivergence_eq_of_cellSlope_basisVec is that display itself: on a cell where the superposed basis slopes are the basis vectors (clause 3 of e.hat.linear.properties, off the collar) the divergence is exactly q. It is the reason hoffG is a theorem here.

The route to the layer envelope, and the constant #

The (2d−2)²-cancellation core vecNormSq_divergenceDeviation_le of CollarLayerEnvelopeG is reused verbatim: if every entry of the deviation family u is at most η, then |(∇·D̂_q)(𝔰) − q|² ≤ (2η)² |q|². What feeds it here is not the coordinatewise Step-2 estimate of the single-mesh branch (no single mesh, hence no kuhnSlope-level bound) but the proved summed active-component envelope, read at the d basis loads:

|∇ℓ̂_{e_i}(𝔰) − e_i|²  ≤  superposedGradConst d ² · 3^{2b(k+h_k)} · |e_i|²

(SuperposedEnvelope.badFamily_vecNormSq_superposedCompetitorCellSlope_sub_le_layerEnvelope at p := basisVec i, with |e_i|² = 1), and a coordinate of a vector is at most its Euclidean norm, so η = superposedGradConst d · 3^{b(k+h_k)} serves.

The constant, itemized honestly. 2η gives

superposedDivConst d = 2 · superposedGradConst d = 2 · M(d) · 648 d = 3888 d · 11^d ,

i.e. the summed gradient constant times 2, and nothing else. A further factor of order d · |q|_{ℓ¹} does not appear, for two reasons, both checkable in the proof: (i) the d entries of the inner sum are priced through the proved local core, whose (d−2)² + 2d(d−2) + d² = (2d−2)² is exactly cancelled by the (d−1)⁻¹ of e.dq, leaving the factor 2 and not a factor d; and (ii) the ℓ¹ size of the load never enters, because the deviation bound fed into the core is an ℓ^∞ bound obtained from the Euclidean envelope at the basis loads (|e_i|_{ℓ¹} = 1), so the ℓ¹ → ℓ² conversion is already inside superposedGradConst d. The comparison with the single-mesh branch is the expected one: there the G-leg constant equals the F-leg's 648 d because the F leg pays an extra d for a general slope p; here the F-leg constant superposedGradConst d already contains that d, so the G leg is 2 × it. Nothing is optimized, and no random quantity, layer index or component enters the constant.

Scope: what is NOT claimed #

This module is the per-cell estimate and the three cell-constant clauses, only.

References #

e.hatdq at the superposed family #

∇·D̂_q at the superposed family, at the manuscript's divergence convention (∇·A)_j = ∑_i ∂_{x_i} A_{ij} (the footnote): the sum over i of the i-th coordinate of the gradient of the (i,j) entry, at the superposition's own defined gradient field.

This is the field whose solenoidality is e.hat.D.bc; that statement is NOT proved here (see the module Scope).

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    The constant value ∇·D̂_q(𝔰) on a cell, read at the cell's interior point exactly as superposedCompetitorCellSlope is.

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      The deviation identity and ∇·D_q = q #

      theorem Algsuperdiff.Section3.Provider.Affine.divergence_sub_eq {d : ℕ} (hd : 2 ≤ d) (q : HCPolySupport.Vec d) (S : Fin d → HCPolySupport.Vec d) :
      (fun (j : Fin d) => ∑ i : Fin d, (↑d - 1)⁻¹ * (q j * S i i - q i * S j i)) - q = fun (j : Fin d) => (↑d - 1)⁻¹ * ((∑ i : Fin d, (S i - HCPolySupport.basisVec i) i) * q j - ∑ i : Fin d, q i * (S j - HCPolySupport.basisVec j) i)

      The deviation identity, as pure algebra on a family of cell slopes. For any family S of vectors (the roles: S i = ∇ℓ̂_{e_i}(𝔰)),

      (∑_i (d−1)⁻¹ ( q_j S_i i − q_i S_j i))_j − q_j
         = (d−1)⁻¹ ( (∑_i (S_i − e_i)_i) q_j − ∑_i q_i (S_j − e_j)_i ) .
      

      The d produced by ∑_i (e_i)_i and the q_j produced by ∑_i q_i (e_j)_i cancel against the (d−1) of e.dq; this is the display ∇·D_q = q in its cellwise form, and it is what makes the left-hand side a deviation.

      The deviation identity at the superposed cell divergence (in cellwise form): with u_i = ∇ℓ̂_{e_i}(𝔰) − e_i,

      (∇·D̂_q)(𝔰) − q = (d−1)⁻¹ ( (∑_i (u_i)_i) q − (u_·ᵀ q) ) .
      

      ∇·D_q = q (the display), cellwise: on a cell where the superposed basis slopes are the basis vectors themselves — the situation of clause 3 of e.hat.linear.properties off the collar — the divergence of D̂_q is exactly q. This is the normalization that makes the deviation identity a statement about a deviation, and it is the reason hoffG below is a theorem.

      The three cell-constant clauses at ∇·D̂_q #

      The G-half of the sum_of_a_decomp clauses at ∇·D̂_q, at one cell.

      • the field is constant on the open cell — every basis slope is (e.hat.linear.properties clause on the superposition), and ∇·D̂_q is built from those pointwise;
      • the constant is 0 when the cell's Whitney cube is bad: every basis slope is 0 there (clause 1), so every entry of D̂_q has zero gradient;
      • the constant is q when the cube lies off 𝒩(ℐ): every basis slope is e_i there (clause 3), and the normalization ∇·D_q = q applies.

      Only the proved superposition clauses are used; no disjointness of collars, no overlap count and no finiteness of the component family enters.

      Over the subtype ↥(simplexPartition m hn) these are literally the hGc, hbadG and hoffG hypotheses of Multiscale.sum_of_a_decomp_cutoff.

      The collar layer envelope of ∇·D̂_q #

      The collar gradient constant of the G leg of the superposed branch, 2 · superposedGradConst d = 3888 d · 11^d: the summed active-component constant times the factor 2 produced by the (2d−2)² cancellation of e.dq. It is the Cgrad of r.gradient.bound.simplified for ∇·D̂_q at the superposed competitor.

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        theorem Algsuperdiff.Section3.Provider.Affine.vecNormSq_superposedCompetitorCellDivergence_sub_le_layerEnvelope {d : ℕ} {M : ABKModel d} {m : ℤ} {b : ℝ} {hs k₀ : ℕ} {omega : Cutoff.CutoffSample d} (hd : 2 ≤ d) (hb0 : 0 < b) (hb : b ≤ 1 / 8) (hk₀ : 3 ≤ k₀) (havoid : ∀ (h : ℕ), hs ≤ h → ∀ u ∈ Percolation.cubeFinset h, ↑(Percolation.badClusterDiam M m h omega u) < 3 ^ (b * ↑h)) {S : Set (HCPolySupport.TriadicCube d)} (hSsub : S ⊆ Whitney.whitneyPartition m (Whitney.whitneyScaleSeq b hs k₀)) (hSbad : ∀ Q ∈ S, omega ∈ BadEvents.bad M Q) (q : HCPolySupport.Vec d) {k : ℕ} {R : HCPolySupport.TriadicCube d} (hRlay : R ∈ Whitney.whitneyLayer m (Whitney.whitneyScaleSeq b hs k₀) k) {T : Whitney.KuhnCell d} (hT : T ∈ Whitney.whitneySimplexCells m (Whitney.whitneyScaleSeq b hs k₀) k R) :

        The collar layer envelope of ∇·D̂_q at the superposed competitor: on every cell of every layer-k Whitney cube

        |(∇·D̂_q)(𝔰) − q|²  ≤  (2 · superposedGradConst d)² · 3^{2 b (k + h_k)} · |q|² .
        

        The route follows the proved single-mesh one at the superposed input: the proved summed active-component envelope at each of the d basis loads e_i bounds every coordinate of u_i = ∇ℓ̂_{e_i}(𝔰) − e_i by η = superposedGradConst d · 3^{b(k+h_k)} (a coordinate is at most the Euclidean length, and |e_i|² = 1), and CollarLayerEnvelopeG's vecNormSq_divergenceDeviation_le turns that into (2η)²|q|², the (2d−2)² of the d − 1 surviving terms being cancelled by the (d−1)⁻¹ of e.dq.

        As in the F leg nothing on the right depends on a component, on a layer of a component or on the sample: the whole random content is in havoid.

        theorem Algsuperdiff.Section3.Provider.Affine.badFamily_vecNormSq_superposedCompetitorCellDivergence_sub_le_layerEnvelope {d : ℕ} {M : ABKModel d} {m : ℤ} {E b : ℝ} {k₀ : ℕ} {omega : Cutoff.CutoffSample d} (hd : 2 ≤ d) (hb0 : 0 < b) (hb : b ≤ 1 / 8) (hk₀ : 3 ≤ k₀) (hne : (Percolation.hsepSet M m E b omega).Nonempty) (q : HCPolySupport.Vec d) {k : ℕ} {R : HCPolySupport.TriadicCube d} (hRlay : R ∈ Whitney.whitneyLayer m (Whitney.whitneyScale M m E b k₀ omega) k) {T : Whitney.KuhnCell d} (hT : T ∈ Whitney.whitneySimplexCells m (Whitney.whitneyScale M m E b k₀ omega) k R) :
        HCPolySupport.vecNormSq (superposedCompetitorCellDivergence m (Whitney.whitneyScale M m E b k₀ omega) (Whitney.badFamily M m (Whitney.whitneyScale M m E b k₀ omega) omega) q T - q) ≤ superposedDivConst d ^ 2 * 3 ^ (2 * (b * (↑k + ↑(Whitney.whitneyScale M m E b k₀ omega k)))) * HCPolySupport.vecNormSq q