Item 19: Triangle compatibility audit

Whether the requirements the forward arrow imposes and the requirements the reverse arrow imposes can hold simultaneously. Audit timing, advisory access, information flow, settlement, reference-process identity, seals, causal influence, trader populations, admissibility, and update timing.

Deliverable shape: a compatibility matrix, not a theorem — every row classified compatible, conditionally compatible, incompatible, or unresolved, each with its evidence. Acceptance check: every listed interface appears as a row with a classification and a stated evidence basis; no row is classified compatible on the strength of an assumption introduced to close it.

Context: prompts/2026-08-11-deference-triangle/REPORT.md; projects/deference/note-dump-2026-08-11/lean-deference/AUDIT.md. A solution ships: the matrix, and for every conditionally compatible row the exact condition. Not permitted: turning unresolved into compatible by assumption, or inventing reverse-arrow assumptions to close the table.