This repository contains a preprint presenting an empirical relaxation frameworkfor disk galaxies, developed using publicly available observational data fromthe SPARC database. The work introduces a two-dimensional relaxation space defined by observationalproxies related to cumulative interaction opportunity and inner dynamical mixing.For practical cataloguing, a scalar relaxation index is constructed andstandardised across the full SPARC sample, yielding a set of fixed relaxationclasses (R-I to R-V).Applied to SPARC galaxies, this framework reveals a continuous relaxationsequence and a systematic progression in inner rotation-curve structure. The present manuscript is intended as an empirical organisational contribution.It does not propose a specific dark-matter particle model, a modification ofgravity, or a definitive physical mechanism.Instead, it provides a coordinate system within which observational data andtheoretical models can be compared on equal footing. The framework builds upon earlier empirical findings on inner-halo organisationand velocity-dependent saturation behaviour, which are archived separately asrelated preprints.Together, these works form a coherent observational programme aimed atstructuring the diversity of galactic rotation curves. The analysis underlying this work was developed through iterative exploration.All quantitative results are derived from real observational data.Details regarding the exploratory workflow and the role of auxiliary tools areprovided here for transparency, but are intentionally kept separate from themanuscript to preserve a conventional scientific presentation. The results are shared to encourage independent reproduction, extension toother galaxy samples or simulations, and further investigation of the physicalprocesses responsible for the observed ordering.
Attilio Riolo (Sun,) studied this question.