Declarations

. Cheung manuscript citations identify the user-supplied documents or excerpts and their supplied versions. Where only excerpts or catalogue descriptions were provided, this is stated in the bibliography. No independent manuscript-registry audit or comprehensive companion-series scan is claimed.

scope. The ideal code, accessible decoders, finite confidence statements, flagged-erasure benchmark, two-tensor patch, and finite-factor subsystem conversion are the explicit locally proved results. Established code and error-correction facts are not presented as new priority claims.

scope. No experimental data, laboratory calibration, hardware access audit, numerical simulation, acceptance-frequency study, or deployment transfer test was supplied or executed here. No empirical claim is inferred from the analytic benchmark.

scope. No successful execution, proof-assistant checking, independently executed symbolic script, referee approval, or journal acceptance is asserted. The source is self-contained for pdfLaTeX and requires no external bibliography file.

scope. No gravitational preparation, bulk–boundary observable dictionary, metric reconstruction, Einstein dynamics, horizon-area identity, island, Page curve, evaporation endpoint, or spacetime-emergence theorem is constructed. These are scope boundaries, not universal impossibility statements.