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LeanPool.Superdiffusion.Algsuperdiff.Section3.Provider.Besov.JBoundByBesov

JBoundByBesov #

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

The J-bound composite of Section 3.5, on the multiscale right-hand side #

This module assembles the estimate of ABK26 l.J.bound.by.Besov for the canonical maximizer on a centred cube, with the negative Sobolev factor of the printed display replaced by the proved multiscale upper bound of this directory. The two structural features of the printed right-hand side that the consumer needs are retained verbatim: the literal factor 2 and the literal depth-one sum \sum_{z \in 3^{m-1}\Zd \cap \cu_m} of the response defects.

Nothing about the status of the lemma l.J.bound.by.Besov is asserted here.

Route #

  1. The digging room. The response of the ordinary central child is the child average of the child half-energy (JUpperBoundWeakNorms.responseJOnCube_eq_cubeAverage_topHalfEnergy); the pointwise polarization \tfrac12 \xi\cdot\s\xi \le \eta\cdot\s\eta + (\eta-\xi)\cdot\s(\eta-\xi) at an elliptic matrix replaces it by the parent energy plus the parent-minus-child difference energy; the difference energies of the other depth-one children are nonnegative and are added; and the summed difference energy is the summed response defect, by the upstream partition identity for the descendant average of the half-difference energy and the response partition defect. The last step is where the literal 2 and the literal depth-one sum are produced.
  2. The Caccioppoli step. CentralChildCaccioppoli.lean bounds the parent-coefficient energy on the ordinary central child by the upstream interior Caccioppoli right-hand side of the parent, and JBesovPrefactor.lean bounds the diagonal prefactor on 0 < s \le 1/4 by a dimension-only envelope times the three displayed factors \Theta^{s/(1-2s)}, \Lambda_{s,1} and 3^{-2m}.
  3. The oscillation step, replacing. OscillationPoincare.lean bounds the parent oscillation L^2 square that the Caccioppoli right-hand side leaves by the square of the coordinate sum of the negative circ Besov norms of the gradient coordinates at (s,p,q) = (1,2,1).
  4. The centring step. Each depth-j circ average of a gradient coordinate is bounded by twice the depth-j circ average of the corresponding coordinate of the gradient defect plus twice the squared coordinate of the comparison vector c = \s_*^{-1}(\cu_m)(q+\k(\cu_m)p) - p, because the descendant average of the gradient is the descendant average of the defect shifted by c. Summing the circ weights, whose total is at most \tfrac32 \cdot 3^m, and passing to the supremum with Homogenization.cubeBesovCircNorm_le_of_forall_entry_le, which is taken one coordinate at a time, by dominating a single coordinate entry with the full coordinate sum and re-summing over the d coordinates, at the cost of a further factor d, converts the coordinate sum of circ norms into the multiscale average sum of the centred gradient plus the length of c.
  5. The coordinate aggregation. The bound produced by step 3 aggregates the coordinates in \ell^1, while the printed multiscale sum aggregates them inside each depth term in the Euclidean norm. Cauchy's inequality in the coordinate index converts one into the other at the cost of \sqrt d, which the dimension-only constant absorbs. This is the conversion that OscillationPoincare.lean records but does not formalize; it is formalized here, in weighted_sum_sqrt_le.

Correspondence with the printed display #

The printed right-hand side is

`C \Lambda_{s,1}(\cu_m) (\Lambda_{s,1}/\lambda_{s,1})^{s/(1-2s)} 3^{-2m} | \nabla v |_{\Hminusul(\cu_m)}^2

The composite below carries \Lambda_{s,1}(\cu_m;\a) as Ch02.LambdaS (originCube d m) s, whose body is the q = 1 convention Ch02.LambdaSq (originCube d m) s (.finite 1); the ellipticity ratio as Ch02.ThetaRatio (originCube d m) s s, whose body is Ch02.LambdaS (originCube d m) s / Ch02.lambdaS (originCube d m) s, raised to s/(1-2s); and the depth-one sum verbatim on descendantsAtDepth (originCube d m) 1, which is the set of the 3^d children z+\cu_{m-1} of \cu_m. Two features differ from the printed display and are load bearing.

  1. The negative Sobolev factor is replaced by its multiscale upper bound. 3^{-2m}\|\nabla v\|_{\Hminusul}^2 is replaced by the square of centredMultiscaleAverageSum, the manuscript sum \sum_{n\le m} 3^{-(m-n)}(\avsum_z|(\nabla v - c)_{z+\cu_n}|^2)^{1/2}. The scale weight 3^{-m} of the printed display is carried inside that sum, by the reindexing n = m-j, exactly as Carriers.scaledNegHMinusOne carries it at the use site. The replacement is in the direction of a weaker estimate: the proved bridge MultiscalePoincareBridge.scaledNegHMinusOne_le_multiscaleAverageSum bounds the negative Sobolev object by the multiscale sum and no reverse comparison is available, so no statement here is equivalent to the printed one. The bridge's own right-hand side is the Euclidean coordinate aggregate of the same circ norms, which lies below the coordinate sum used here; the comparison is therefore in the stated direction only up to the √d coordinate aggregation, and no declaration in this directory compares the negative Sobolev object to the multiscale average sum directly.
  2. The centring term is explicit. Because the multiscale sum of item 1 is the sum of the centred gradient, the centring of step 4 leaves the summand |c|, written Real.sqrt (vecNormSq (coarseScaleSeparation ...)). Squared, it is exactly the third summand of the consumer display at , C \shom_L \E [ | \s_{L,*}^{-1}(\cu_m)(q+\k_L(\cu_m)p) - p |^2 ], so the consumer already carries it. The manuscript's own copy of that summand comes from squaring the fourth printed term of e.Besov.norms.gradient, which carries the discount 3^{-(m-L_0)}; the term produced here carries none, matching the undiscounted form. It is therefore a second, independent copy of the same summand, which the consumer's constant absorbs. It is kept explicit rather than absorbed.

Formalization readings #

The readings of Carriers.lean, PerScaleDefect.lean and BesovNorms.lean (the pairing is volume normalized; a vector field's dual seminorm is the Euclidean \ell^2 aggregate; the index set z \in 3^n\Zd \cap \cu_m is the set of triadic descendants at depth m-n and \avsum is descendantsAverage; the bi-infinite sum over n \le m is the supremum of its partial sums) are inherited unchanged. One further reading is specific to this module.

The multiscale average sum is the supremum of its partial sums. centredMultiscaleAverageSum is ⨆ N, \sum_{j < N} 3^{-j}(\ldots)^{1/2}. The supremum is finite: partialMultiscaleSum_le_fourTerm bounds every partial sum by the four printed terms of e.Besov.norms.gradient, at the admissible parameters L_0 = m, s = 1/4 and r = \infty, so the defining family is bounded above and centredMultiscaleAverageSum_le_fourTerm transfers the four-term bound to the supremum itself at every admissible parameter choice.

Scalar helpers #

The circ entry at (s,p,q) = (1,2,1) #

The centred multiscale average sum #

The manuscript multiscale average sum \sum_{n \le m} 3^{-(m-n)} ( \avsum_{z} | (\nabla v - c)_{z+\cu_n} |^2 )^{1/2} , for the canonical maximizer gradient defect on \cu_m and the comparison vector c = \s_*^{-1}(\cu_m)(q+\k(\cu_m)p) - p.

The reindexing n = m - j turns the printed discount 3^{-(m-n)} into 3^{-j} and the printed index set z \in 3^n\Zd \cap \cu_m into the triadic descendants at depth j; the bi-infinite sum over n \le m is the supremum of the partial sums, exactly as in BesovNorms.lean.

Equations
  • One or more equations did not get rendered due to their size.
Instances For

    Every partial multiscale sum is bounded by the four printed right-hand terms of e.Besov.norms.gradient. This is the proved four-term display of BesovNorms.lean, restated at an arbitrary truncation of the depth range.

    The multiscale average sum obeys the four-term display of l.Besov.norms. This is the form in which the composite below meets the proved e.Besov.norms.gradient estimate.

    The centring step #

    The centring step. The scaled coordinate sum of the negative circ norms of the maximizer gradient is bounded by the multiscale average sum of the centred gradient plus the length of the comparison vector, with a dimension-only constant. The second summand is the term the manuscript already carries, squared.

    The subadditivity digging room #

    The composite #

    theorem Algsuperdiff.Section3.Provider.Besov.exists_responseJ_centralChild_le_jBoundByBesovDisplay (d : ℕ) [NeZero d] :

    The composite, with the negative Sobolev factor replaced by its proved multiscale upper bound. For the canonical maximizer on \cu_m, the response of the ordinary central child \cu_{m-1} is bounded by a dimension-only constant times the coarse upper ellipticity \Lambda_{s,1}, times the coarse ellipticity ratio raised to s/(1-2s), times the square of the multiscale average sum of the centred gradient plus the length of the comparison vector, plus the literal depth-one sum of twice the response defects.