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Shadow Theory

Section 11 9 October 2026

The quantitative cost of the anisotropic continuity route

Reading position 12 of 16

11 The quantitative cost of the anisotropic continuity route

Proposition 11.1 (A flat embedding bound with the physical factors retained)

Let a localized extension uu on one radial and seven tangent Euclidean coordinates satisfy ∥u∥2≤e\|u\|_2\leq e and ∥u∥Hr2Htan4≤M\|u\|_{H^2_rH^4_{\rm tan}}\leq M. With unitary Fourier convention and θ=15/16\theta=15/16,

∥u∥∞≤Cθe1/16M15/16,Cθ2≤15616π5<10−4. \|u\|_\infty\leq C_\theta e^{1/16}M^{15/16},\qquad C_\theta^2\leq\frac{15}{616\pi^5}<10^{-4}. (11.1)

On physical charts the localization, extension, coordinate Jacobian and any half-density constants must multiply this flat bound.

Proof

Fourier Hölder bounds the Hr2θHtan4θH^{2\theta}_rH^{4\theta}_{\rm tan} norm by e1−θMθe^{1-\theta}M^\theta. Cauchy in the evaluation integral gives

Cθ2=(2π)−8I1(2θ)I7(4θ),Im(s)=∫Rm(1+∣ξ∣2)−sdξ. C_\theta^2=(2\pi)^{-8}I_1(2\theta)I_7(4\theta),\qquad I_m(s)=\int_{\mathbb R^m}(1+|\xi|^2)^{-s}d\xi .

The strict thresholds are 2θ>1/22\theta>1/2 and 4θ>7/24\theta>7/2. For the displayed rational upper bound no special-function evaluation is needed. Splitting each integral at radius one,

I1(15/8)≤2(1+4/11)=30/11,I7(15/4)≤∣S6∣(1/7+2)=16π3/7. I_1(15/8)\leq2(1+4/11)=30/11,\qquad I_7(15/4)\leq |S^6|(1/7+2)=16\pi^3/7.

Here ∣S6∣=16π3/15|S^6|=16\pi^3/15. Multiplying and dividing by (2π)8(2\pi)^8 gives 15/(616π5)15/(616\pi^5); the elementary lower bound π>3.14\pi>3.14 proves it is below 10−410^{-4}.

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For two waves, the density difference obeys ∥ρ−ρ~∥∞≤(∥ψ∥∞+∥ψ~∥∞)∥ψ−ψ~∥∞\|\rho-\widetilde\rho\|_\infty \leq(\|\psi\|_\infty+\|\widetilde\psi\|_\infty) \|\psi-\widetilde\psi\|_\infty. Thus the genuine product graphs can supply a common positive-density tube for Theorem 5.1. They supply only the slow error exponent 1/161/16 in the eight-coordinate case. The compact COM radius enters the tangent ellipticity constant; physical source widths enter the profile derivatives; chart and extension factors remain; and the propagated graph constants can be large. The flat number below 0.010.01 is consequently not a numerical record-error certificate or a small physical stability coefficient. It is the explicit analytic link between an attained common-form/graph comparison and the positive-tube hypothesis of the whole-history theorem.