Structural Constraints on Effective Cosmological Ratios from Pre-Geometric Tripartition

This technical note analyzes the structural constraints that restrict the range of admissible cosmological component ratios in a pre-geometric framework. The goal is not to predict numerical values such as 5:27:68, but to show why only a three-sector decomposition is structurally stable and why the effective ratios must lie within a finite admissible band. The analysis is purely structural and does not rely on geometry, dynamics, or observational modeling.