Structural Differentiation Cosmology (SDC) v1.1: Cosmic Expansion as a Projection of Internal Relational Reconfiguration

Structural Differentiation Cosmology (SDC) is a minimal and falsifiable cosmological framework in which the observed cosmic expansion is interpreted as an effective projection of irreversible internal relational differentiation within an externally closed universe. Instead of introducing dark energy or additional physical entities, SDC models cosmic acceleration as an emergent observational effect arising from the evolution of a bounded structural density variable. The framework provides explicit dynamical equations, well-defined observational mappings, and a clear criterion distinguishing SDC from ΛCDM using redshift-dependent observables. Version 1.1 refines the theoretical formulation and incorporates an explicit coarse-graining interpretation and updated figure structure, while remaining fully consistent with the core assumptions of the model.