WHERE THE INTERSECTIONS WEAVE — III Observational Search for Projection Inversion in Type Ia Supernova Residuals

Abstract

Version 2 update:This version preserves the original Version 1 text and adds an addendum evaluating the redshift-dependent sign-reversal structure as a whole. Using the positive and negative redshift bands identified in the original analysis, a 4,000-realization permutation test gives T=0.0504 with a one-sided p=0.048 for half-width 0.05, and T=0.0293 with p=0.127 for half-width 0.075. Because the redshift-band boundaries were identified from the same Pantheon+ data, these values are treated as descriptive rather than as independent confirmatory significance tests. The addendum also includes an axis-robustness check and fixes the redshift bands, test statistic, regression method, and permutation procedure in advance for application to future independent SN Ia data. Only that future independent application is designated as confirmatory.