L1 Paper 5 Neutrino mixing invariants

This paper identifies the invariant structure underlying neutrino mixing within admissible local descriptions and shows that such invariants are fixed once standing preservation, admissibility, and identity persistence are imposed. The analysis is eliminative: it demonstrates that mixing relations admit only a limited set of invariant quantities, and that attempts to introduce additional independent invariants either collapse equivalence classes or violate compositional closure. Neutrino mixing is treated as a representational feature of admissible coupling relations rather than as a primitive dynamical process. The paper shows that invariance under rephasing and admissible redescription exhausts the available degrees of freedom, leaving no residual parameters that can be freely adjusted without structural violation. No primitives, mechanisms, or calculational schemes are introduced. The contribution is boundary-setting: it clarifies why neutrino mixing invariants are fixed features of admissible local skins and why further freedom is structurally inadmissible rather than empirically unconstrained