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LeanPool.Superdiffusion.Algsuperdiff.Section4.Provider.ExcessDecay.BoundaryAssemblyEnergy

BoundaryAssemblyEnergy #

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

The boundary-regime Caccioppoli display, with the ∇h legs #

l.coarse.grained.Caccioppoli.RHS: with v the Dirichlet solution carrying the same force and the same boundary datum, the difference u - v has global zero trace, solves the homogeneous equation, and CoarseGraining's zero-datum theorem applies to it (exists_boundaryCaccioppoliEnergy_ofDifference). Three steps separated that from the printed display; this module proves all three and closes it.

  E_core(∇u)  ≤  2 E_core(∇(u-v))  +  2 E_core(∇v)          (i)   Minkowski
  E_core(∇v)  ≤  18^d · E_{□_m}(∇v)                         (ii)  volume ratio
  E_{□_m}(∇v) ≤  (Dirichlet energy RHS)²                    (iv)  e.cg.RHS

Step (iv) is CoarseGraining's energyConsequencesRHSTheory, whose right-hand side dirichletEnergyWithRHSRHS carries both printed legs: the force leg [g]_{B^r} and the boundary leg ‖∇h‖_{B^r} at dirichletBoundaryGradientField v = ∇h. That is where the anchor's ∇h terms enter, and it is the whole point of the boundary lane.

The constant, honestly #

The right-hand side proved here is CoarseGraining's own dirichletEnergyWithRHSRHS squared, times 2 · 18^d, not the printed normalization t^{-3} Λ_t ‖∇h‖²_{H^{2t}(□_0)}. No exponent has been moved: the two legs are CoarseGraining's, at CoarseGraining's exponent r ∈ (0,1) (kept free and separate from the Caccioppoli pair s, t, since the two CoarseGraining theorems do not share a normalizer), and the geometric loss 18^d and the Minkowski factor 2 are explicit. The printed t^{-3}Λ_t shape would require CoarseGraining's energy theorem restated at the Caccioppoli normalizer, which is not available and is not attempted.

References #

1. The quadratic-form Minkowski step #

The Minkowski step of the printed display.

On the Caccioppoli core the coefficient energy of u is at most twice the energy of u - v plus twice the energy of v. This is the quadratic-form triangle inequality ‖σ^{1/2}∇u‖² ≤ 2‖σ^{1/2}∇(u-v)‖² + 2‖σ^{1/2}∇v‖², with CoarseGraining's own decomposition lemma doing the work.

2. The core-volume ratio #

The core-volume ratio. A core average of the nonnegative coefficient energy density is at most 18^d = 2^d 3^{2d} times the parent-cube average: |□_m| / |caccioppoliCoreSet □_m x| ≤ 2^d 3^{2d} for x ∈ □_m.

3. The parent energy is the square of CoarseGraining's energy norm #

4. The printed boundary display, with the ∇h legs present #