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Shadow Theory

Appendices C and D: reconstruction and scope

Derive the reconstruction fixture and distinguish three different equivalences.

C. Analytic checks behind the reconstruction table

For the triangular matrix in §8, the diagonal entries solve u22′=−2tu22u'_{22}=-2tu_{22} and u11′=−tu11u'_{11}=-tu_{11}. Variation of constants gives

u12(t)=−e−t2/2∫0te−s2/2 ds.(71)u_{12}(t)=-e^{-t^2/2}\int_0^t e^{-s^2/2}\,ds . \tag{71}

This yields (64) without a numerical differential-equation solver. The induced infinity norms satisfy ∥A∥≤2\|A\|\le2 and ∥A′∥≤2\|A'\|\le2. Over length hh the fundamental solution has norm at most e2he^{2h} and second derivative (−A′+A2)U(-A'+A^2)U. Taylor's integral remainder bounds the Euler defect by 3h2e2h3h^2e^{2h}. The other exact and Euler factors in the telescoping product contribute at most e2(1−h)e^{2(1-h)}. Summing over NN equal intervals gives a global bound 3e2/N3e^2/N, already smaller than the declared 3e2.2/N3e^{2.2}/N used in the saved comparison. No contractivity assumption is used.

For the oscillatory curvature control, take A1=(sin⁡(kx0)/k)E01A_1=(\sin(kx^0)/k)E_{01} and all other Aμ=0A_\mu=0. Since E012=0E_{01}^2=0, the exact path exponential is I−E01∫sin⁡(kx0) dx1/kI-E_{01}\int \sin(kx^0)\,dx^1/k. The error from identity is O(k−1)O(k^{-1}) on bounded-length path families. Along x0=x1=sx^0=x^1=s the integral is (1−cos⁡k)/k2(1-\cos k)/k^2, but ∂0(A1)01=cos⁡(kx0)\partial_0(A_1)^0{}_1=\cos(kx^0) gives R11(0)=1R_{11}(0)=1. This explicit limit distinguishes transport and curvature reconstruction, explaining the derivative norms in (16).

D. Scope of the recovery statements

There are three equivalences with different meanings.

  1. Regular source transports and affine generators are off-shell inverse representations, including their allowed variations.
  2. At fixed nondegenerate density, projective classes of generators and volume-restored transports are off-shell inverse representations.
  3. The unrestricted affine action reduces to the metric Einstein–matter equations after its algebraic field equation eliminates nonprojective distortion. This is where the original torsion-free parent and the unrestricted quotient agree. Their off-shell connection dimensions, 40 and 60 respectively, exhibit the difference.

The results are local in the declared smooth sector, or apply to global histories with patching and boundary data obeying these contracts. A nontrivial tangent bundle requires compatible local frames and transport descent. The finite fan does not determine arbitrary global topology, singular extension or an all-sector Shadow equalizer. None of those enlargements is needed for the full local nonlinear Einstein–matter result.

Published source: Transport and Projective Reduction in a Source–Readout Derivation of Einstein Gravity. Read the original PDF alongside the web treatment.