Hyperbrane Relativity (HBR) describes the observable universe as a dynamical 3-brane uniformly translating in the -W direction within a flat 4D Euclidean bulk. The empirical 3D light speed c is identified with the gate-inflow speed at the dimensional boundary Sigma = w = wbrane (t) via a Dirichlet-type condition (dot XW |Sigma = c) ; E = mc² then arises as a geometric identity from the self-contraction |Uᵢnflow|² = c². Lorentz invariance is treated as an emergent brane symmetry, not a fundamental postulate. The framework yields a single-parameter modification beta of general relativity through the field equation Gₘunu + beta Hₘunu = 8 pi Tₘunu, with weak-field expansion Phi = 1 + PhiN/c² + beta PhiN²/c⁴ and PPN metric g₀0 = -1 + 2U - 2 beta U². Key observational results carried over from prior versions: PPN constraint |beta - 1| 30. V28 introduces the central new theoretical contribution (Core Novelty 9): the brane thickness Delta-w is identified as the universal crossover scale that simultaneously controls (i) the strong-field force-law transition between the near-field 1/r⁴ singularity-avoidance regime (r > Delta-w), and (ii) the Observation-Contact Separation underlying quantum measurement, with the contact regime |Delta-kappa| L > 1). Appendix B now opens by referencing the Delta-w unification, making explicit that the Born rule derivation and OCS theorem are not independent results but consequences of a single geometric scale. Released under CC-BY-4. 0. PDF includes both English and Japanese editions.
Yuichi Yamamoto (Wed,) studied this question.