# GRAV-BRIDGE-I.1 — Frozen Full-Curve Audit Protocol

The primary model is the parent `M2` baseline plus three fold-local principal components from each complete STRUC-I curve family:

- `rho(kappa)`;
- `1 - A_kappa(kappa)`;
- `nu(V_kappa)(kappa)`.

PCA is fitted on unique training galaxies only. Test galaxies are transformed by the training-fold scaler and PCA. The exact archived five-fold galaxy registry is reused.

Whole curve bundles are permuted among training galaxies and among test galaxies separately inside each fold. This destroys the correct galaxy-to-curve assignment without crossing the outer validation boundary.

A robust primary signal requires: at least 1% held-out RMSE improvement, curve-null p <= 0.05, a positive paired-galaxy bootstrap lower bound, and improvement in at least three of five folds.

The parent GRAV-BRIDGE-I v0.1.0 verdict remains unchanged regardless of the audit outcome.

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## v0.3 project interpretation

This document belongs to the external transfer experiment. Numerical, technical, protocol, or provenance content above is preserved. The transfer result tests one static global architecture: it does not negate the galaxy-specific structural information carried by the curves. Complete curves retain identity, and ρ is the leading channel for local or regime-conditioned follow-up.

