Lluis Eriksson (2026). Sharp marginal-erasure bounds and positive completion of nonunital quantum channels. AIRR.SCIENCE, ARR-2026-3K6NV742FP8WH8K9, v1. https://airr.science/papers/ARR-2026-3K6NV742FP8WH8K9/versions/v1/ Research preprint; ARR-2026-3K6NV742FP8WH8K9 v1. Not peer reviewed by AIRR. Working paper; not admitted to the AIRR accepted collection.