The Irreversibility Frontier (EA-SEI-IRREVERSIBILITY-FRONTIER-01 v1.0) is the comparative-architecture paper of the Semantic Economy Institute's accelerator selection-metrology program, deposited under the Nobel Glas heteronym.
It defines the irreversibility frontier as the earliest stage at which an event-content-dependent transformation or gate can permanently eliminate a scientifically relevant distinction without a sufficiently independent durable record from which that loss can later be audited. Because a detector may hold several frontiers at different fidelity levels, the paper refuses a scalar score and describes an architecture instead by an Irreversibility Profile: the tuple of fidelity locus, entering rate, surviving fraction, replay horizon, bypass channels, and selector class. Its governing claim is that the scientifically decisive variables are the locus and the bypass — not the presence of machine learning.
The paper separates representational from retention irreversibility, distinguishes semantic depth from physical depth, and applies the profile comparatively across CMS, ATLAS, LHCb, CBM, and Belle II — from early irreversible selection with emerging side channels through free streaming that defers event ontology entirely. It closes on the No-Retention-Bound observation: stage-level validation on design support bounds nothing about end-to-end retention outside that support.
This deposit supersedes the term irreversibility locus introduced in the Iceberg Document (#1450); citations to the locus resolve here.