This preprint presents Structural Rotation Test (SRT) v2.3, a minimal and falsifiable observational framework designed to distinguish between geometric rotation in General Relativity and structural rotation in Structural Differentiation Gravity (SDG). Rather than treating rotational gravity solely as a consequence of spacetime geometry, SRT examines whether rotational phenomena can be interpreted as observable manifestations of structural differentiation within a closed relational system. The framework introduces a direct comparison between SDG-based rotational predictions and standard GR-based expectations using residual structure, fitting behavior, and decision-level observational criteria. Version 2.3 focuses on the observational discriminability of the two frameworks. It provides a compact decision structure, illustrative fitting comparisons, and residual-based diagnostics that clarify how future observations may separate geometric and structural interpretations of rotation. This upload includes the full preprint PDF, the figure-generation Python script, and all figures used in the manuscript.
Koji Okino (2026) studied this question.