A Relative Element-Branch Closure of C/N/O/S in the U131 Reconstruction of the Standard Genetic Code

This paper presents Paper 058 of the U131 research series. Building on Paper 057, which established a complete scalar reconstruction of the standard genetic code, this work isolates a relative C/N/O/S element-branch closure within the U131 reconstruction pipeline.Starting from the U131 minimal carrier kernel, the construction generates C/N/O/S element vectors, normalized relative element constants, scalar property scores, 21 sidechain topology classes, and 21 sidechain blueprints. After the name-free generation phase is completed, an evaluation ledger is opened and the standard genetic code is reconstructed with 64/64 agreement.The frozen v1311-v1320 audit returns 9/9 exact checks. It verifies name-free generation, absence of measured constants in the generation process, 64/64 standard-code reconstruction, external rank-proxy alignment, a permutation no-go test, and an explicit boundary that absolute measured atomic constants are not derived.The paper therefore claims a relative element-branch closure of C/N/O/S, not a full absolute ab-initio derivation of quantum-chemical constants.