TRAC: Operational Framework for Late-Time Black-Hole Isolation in an Asymptotically Accelerated Universe

TRAC presents an operational framework for identifying and characterizing the late-time transition of black holes toward effective isolation in an asymptotically accelerated universe. Rather than proposing a modification of general relativity or a microphysical model of the final evaporation stage, the framework provides reproducible operational criteria for distinguishing effective isolation from later scenario-dependent evolution.The manuscript introduces two main milestones: TRAC-iso, marking the onset of effective isolation, and TRAC-sign, marking the coarse-grained sign change of the net mass flow when such a transition occurs. It also defines an Isolation Aftermath Map (IAM) with the classes IAM-E, IAM-P, and IAM-R to classify the post-isolation regime.Within the Hawking baseline considered in the paper, the framework shows that the ratio between isolated residual accretion and Hawking mass loss scales structurally as R(M) ∝ M^3, implying that supermassive black holes may remain in an accretion-dominated aftermath for extremely long times even after effective causal feeding has ceased.The work includes explicit conventions, a coarse-graining prescription, a practical application pipeline, minimal robustness checks, and representative late-time scenarios. Its aim is to provide a clear and reproducible conceptual and operational basis for discussing black-hole isolation, residual late-time feeding, and the distinction between effective isolation and eventual evaporation in de Sitter-like cosmology.