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LeanPool.Superdiffusion.Algsuperdiff.Section24.Sensitivity.Provider.DhBound.Discharge.ConstantBesov

ConstantBesov #

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

The negative Besov seminorm of a constant vector field #

Source: ABK26, the third summand of the three-way split of ∇u = ∇w + ∇w* + ℓ_p inside e.split.besov.stuff.begin: the affine piece ℓ_p contributes the constant gradient p, whose concrete negative Besov seminorm is a pure geometric series.

Every descendant average of a constant field is that constant, so

[c]_{B^{-s}_{2,2}(Q), N} = |c| ( ∑_{j ≤ N} 3^{-2 s j} )^{1/2}
                         ≤ |c| (1 - 3^{-2s})^{-1/2}          (0 < s).

The bound is uniform in the depth N, so it also bounds the infinite-depth sSup seminorm, and it exhibits the required BddAbove witness.

The depth-level quantities of a constant field #

The geometric constant #

The finite-depth bound #