L1 Paper 8 Unitary Mixing Saturation

This paper establishes that unitary mixing freedom within admissible local descriptions is finite and saturates once standing preservation, admissibility, and identity persistence are fixed. The analysis is eliminative: it shows that beyond a limited set of admissible mixing relations, further unitary freedom collapses distinguishability required for standing or reintroduces illicit scope transport under composition. Unitary mixing is treated as a representational redundancy rather than a primitive structural degree of freedom. The paper demonstrates that admissible mixing relations exhaust their capacity to encode differentiation without degenerating into equivalence collapse or deferred admissibility. As a result, mixing matrices are shown to be structurally bounded objects rather than continuously extensible modeling choices. The paper introduces no new primitives and provides no constructive procedures. Its contribution is boundary-setting: it clarifies why unitary mixing must saturate in any standing-preserving local skin, and why attempts to extend mixing freedom beyond this bound are structurally inadmissible rather than empirically disfavored.