Structural Gravity Theory (SGT) v1.3 investigates whether gravity can emerge from a primitive relational substrate rather than being fundamental. The framework introduces the structural constraint C = R − D as the gap between required and realised differentiation of structure, which sources a structural constraint field χ. This field generates dual gravitational potentials (Φ, Ψ) and an effective metric that reproduces the weak-field predictions of General Relativity in the limit χ → 0. Version 1.3 shifts the emphasis from illustrative examples to observation-based quantitative validation. A compact parameter set (ηₛ, γₛ, βₛ, cₛ, D₍C₎, τ₍C₎) is explicitly mapped to observable channels and constrained through a reproducible Bayesian verification framework using Solar-System dynamics, Lunar Laser Ranging, VLBI astrometry, binary pulsars, GW170817, and cosmological observations. This release contains: Main paper (27 pages) Complete figure set (18 framework figures) Standalone PNG figures Reproducibility documentation Citation metadata Zenodo metadata Version history Scope SGT v1.3 is a conceptual and exploratory framework rather than a fitted physical theory. Numerical values and parameter bounds are representative sensitivity targets unless explicitly associated with published observational measurements. Released under the Creative Commons Attribution 4.0 International (CC BY 4.0) license.
Koji Okino (Sun,) studied this question.