SA_2 The AMetric Boundary as Non Transmissive Interface

This paper establishes the AMetric Boundary as a non-transmissive interface separating admissible description from illicit scope transport. The boundary is shown to be structural rather than dynamical: nothing crosses it by inference, extrapolation, parameter transport, or representational continuity. By exhaustion, any attempt to treat the boundary as permeable—whether via limiting procedures, emergent narratives, or meta-descriptive projection—violates admissibility and fails closed. The result is purely classificatory and necessity-based, placing on record that the AMetric Boundary functions as a hard interface required for standing preservation, without introducing traversal methods, mappings, or operational criteria.