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Shadow Theory

Section 24 4 October 2026

Conditional-rank stability with zero fibres included

Reading position 27 of 37

24 Conditional-rank stability with zero fibres included

This section supplies the nonlinear step behind the radial proof. It is useful precisely because the actual clock/pointer marginal need not have a positive lower bound. Let q=ψ(S,⋅)q=\psi(S,\cdot) be a radial spinor slice, u=ψSu=\psi_S, z=ψSSz=\psi_{SS}, a=∥q∥a=\norm q, η=q/a\eta=q/a, and let PrP_r multiply by 1[0,r]\one_{[0,r]}. Set K=⟨η,Prη⟩K=\langle\eta,P_r\eta\rangle and Zη=(Pr−K)ηZ_\eta=(P_r-K)\eta. The constant clock carrier is removed from all derivatives, but its actual drift is retained in continuity.

Lemma 24.1 (Exact weighted rank current)

On nonzero fibres, with κ=ℏ/M\kappa=\hbar/M,

ρ dK dt=F[ψ]=κ{2ℑ(η(r)†u(r))ℜ⟨Zη,u⟩−a∣η(r)∣2ℑ⟨Zη,z⟩}. \rho\frac{\dd K}{\dd t}=\mathcal F[\psi] =\kappa\left\{2\Im(\eta(r)^\dagger u(r)) \Re\langle Z_\eta,u\rangle -a|\eta(r)|^2\Im\langle Z_\eta,z\rangle\right\}. (12)

For two live conditioning coordinates S,ZS,Z, the right side is the sum of the corresponding two functionals, with coefficients ℏ/M\hbar/M and 1/(μZT0)1/(\mu_ZT_0) respectively.

Proof

Write w=∫ρ drw=\int\rho\dd r, Ar=∫0rρ dyA_r=\int_0^r\rho\dd y, and K=Ar/wK=A_r/w. Let δB\delta B and δj\delta j be the cumulative and full clock-current integrals after subtracting the constant carrier. Continuity and zero origin flux give

 dK dt=δJρKS−∂SδB−K∂Sδjw. \frac{\dd K}{\dd t} =\frac{\delta J}{\rho}K_S -\frac{\partial_S\delta B-K\partial_S\delta j}{w}.

The radial current has cancelled pointwise against Krr˙K_r\dot r. Now KS=2ℜ⟨q,(Pr−K)u⟩/a2K_S=2\Re\langle q,(P_r-K)u\rangle/a^2 and ∂SδB−K∂Sδj=κℑ⟨q,(Pr−K)z⟩\partial_S\delta B-K\partial_S\delta j =\kappa\Im\langle q,(P_r-K)z\rangle; the u†uu^\dagger u term is real. Substitution proves (12). Applying continuity with both transverse currents gives the two summands, not an additional mixed-derivative term. Each local product sums the original spinor components. No component has been sampled as an actual sector.

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Lemma 24.2 (Stability without an exact-marginal denominator)

For normalized ψ,G\psi,G, write E=ψ−GE=\psi-G, and suppose the quantities

D=∥E∥,e1=∥ES∥,e2=∥ESS∥,gj=∥∂SjG∥,QG2=∫∥GS(S,⋅)∥4∥G(S,⋅)∥2 dS D=\norm E,\quad e_1=\norm{E_S},\quad e_2=\norm{E_{SS}},\quad g_j=\norm{\partial_S^jG},\quad Q_G^2=\int\frac{\norm{G_S(S,\cdot)}^4}{\norm{G(S,\cdot)}^2}\dd S

are finite. The ratio is zero where GG and its required derivatives vanish. Then

∥F[ψ]−F[G]∥1≤ℏM(4g1e1+2e12+14DQG+9Dg2+e2). \norm{\mathcal F[\psi]-\mathcal F[G]}_1 \le\frac\hbar M (4g_1e_1+2e_1^2+14DQ_G+9Dg_2+e_2). (13)

Here F[G]\mathcal F[G] is algebraic evaluation, including whatever residual the comparison has under the actual equation.

Proof

At a fixed slice put g=G(S,⋅)g=G(S,\cdot), b=∥g∥b=\norm g, ξ=g/b\xi=g/b, U=GSU=G_S, V=GSSV=G_{SS}, and d=∥q−g∥d=\norm{q-g}, d1=∥u−U∥d_1=\norm{u-U}, d2=∥z−V∥d_2=\norm{z-V}. The elementary estimates

∥η−ξ∥≤2d/b,∥Zη∥≤1/2,∥Zη−Zξ∥≤3∥η−ξ∥,∥∣η∣2−∣ξ∣2∥1≤2∥η−ξ∥ \norm{\eta-\xi}\le2d/b,\quad \norm{Z_\eta}\le1/2, \quad\norm{Z_\eta-Z_\xi}\le3\norm{\eta-\xi}, \quad\norm{|\eta|^2-|\xi|^2}_1\le2\norm{\eta-\xi}

follow by adding and subtracting q/bq/b, by projection variance, and by ∣Kη−Kξ∣≤2∥η−ξ∥|K_\eta-K_\xi|\le2\norm{\eta-\xi}. Split the first term of (12) first in u−Uu-U and then in normalized directions. Its derivative part is at most 4∥U∥d1+2d124\norm U d_1+2d_1^2; its direction part is at most 7∥η−ξ∥∥U∥2≤14d∥U∥2/b7\norm{\eta-\xi}\norm U^2\le14d\norm U^2/b. For the second term, the z−Vz-V part is at most ad2ad_2. Splitting the remaining amplitude, density and projection yields (d/2+4b∥η−ξ∥)∥V∥≤9d∥V∥(d/2+4b\norm{\eta-\xi})\norm V\le9d\norm V. Integrate these inequalities and use Cauchy–Schwarz and ∫a2 dS=1\int a^2\dd S=1. If a=0a=0, direct bounding of F[G]\mathcal F[G] works with d=bd=b; if b=0b=0 and its derivatives vanish, the bound 2d12+ad22d_1^2+ad_2 suffices. Thus zero fibres are included, not discarded.

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For G=ϕ(S−Sc−vt)u(S,r)G=\phi(S-S_c-vt)u(S,r) with real ϕ\phi and normalized uu,

QG≤∥ϕ′2/ϕ∥2+sup⁡S∥uS∥2,∥ϕ0′2/ϕ0∥2=4π2σ2335. Q_G\le\norm{\phi'^2/\phi}_2+\sup_S\norm{u_S}^2, \qquad \norm{\phi_0'^2/\phi_0}_2 =\frac{4\pi^2}{\sigma^2}\sqrt{\frac3{35}}.

The last equality is a direct trigonometric integral for the unsmoothed cosine packet. Positive convolution and weighted Cauchy–Schwarz give ϕ′2/ϕ≤Z−1κ∗(ϕ0′2/ϕ0)\phi'^2/\phi\le Z^{-1}\kappa*(\phi_0'^2/\phi_0); Young's inequality then adds only the normalization multiplier at most 1.0000011.000001. No actual conditional law is asserted uniform in this argument.

Lemma 24.3 (Deterministic-time CDF interface)

For every measurable radial cut b(S)b(S),

∫w(S)∣Kψ(S,b(S))−KG(S,b(S))∣ dS≤2∥ψ−G∥. \int w(S)|K_\psi(S,b(S))-K_G(S,b(S))|\dd S\le2\norm{\psi-G}.

Under the already transported actual-law cap CC, the corresponding binary-test mismatch is at most 2C∥ψ−G∥2C\norm{\psi-G} per cut.

Proof

Multiply the CDF difference by w=∫∣ψ∣2w=\int|\psi|^2. The exact identity is

w(Kψ−KG)=∫(1r≤b−KG)(∣ψ∣2−∣G∣2) dr. w(K_\psi-K_G)=\int(\one_{r\le b}-K_G)(|\psi|^2-|G|^2)\dd r.

The coefficient has modulus at most one and the density difference has L1L^1 norm at most 2∥ψ−G∥2\norm{\psi-G}. Uniformity of the exact rank under its own conditional wave measure identifies this integral with the test mismatch. Domination then supplies the actual-law bound. Zero comparison fibres are charged by their exact mass. The same proof works with live conditioning pair (S,Z)(S,Z). It is a fixed-time result; it is not substituted at a random clock hitting time.

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