Lluis Eriksson (2026). Machine-Checked Extended Gauge Invariance at an SU(2) Crossing: Four-Edge Wilson Holonomy, Haar-Preserving Quotient Coordinates, and Reduction to the Ward Chart. AIRR.SCIENCE, ARR-2026-0JTZHGRV1C8G98TM, v1. https://airr.science/papers/ARR-2026-0JTZHGRV1C8G98TM/versions/v1/ Archived manuscript; ARR-2026-0JTZHGRV1C8G98TM v1. Not peer reviewed by AIRR. Historical import; not assessed by AIRR.