Complex Carrier and Norm-Preserving Evolution: The Next Forced Symmetry Class

Closed evolution forces norm-preserving symmetry on the minimal complex carrier. This paper continues a forced-sequence program deriving only what is structurally required by prior steps. Given a phase-bearing summary with phase-invariant quadratic yield, we show that faithful representation of continuous compact phase requires a two-dimensional real realization (equivalently, a complex carrier). Defining closed evolution as internal yield-preserving update, we show that yield-preserving additive maps are pressured into the norm-preserving symmetry class (unitary-like, with antiunitary-like orientation reversal remaining logically admissible). The forward pressure is toward interaction via non-commutation when multiple contexts/operators coexist, and toward generator structure from refinement-stable incremental composition. V2- Minor clarifications only (no change in claims): minimality of U(1), antiunitary permissibility, and tighter non-commutation forward linkage.