Lluis Eriksson (2026). A four-qubit criterion for entropy minimax duality: Minimality, sharp Renyi threshold and a W-state counterexample. AIRR.SCIENCE, ARR-2026-68GTBBQT1T83QATJ, v1. https://airr.science/papers/ARR-2026-68GTBBQT1T83QATJ/versions/v1/ Research preprint; ARR-2026-68GTBBQT1T83QATJ v1. Not peer reviewed by AIRR. Working paper; not admitted to the AIRR accepted collection.