{"id":"live-projection-exactly-once-via-position-guard","text":"Live projections achieve exactly-once processing semantics through three reinforcing mechanisms: position-guarded deduplication prevents double-processing during overlapping catch-up and subscription, position advances even for events with no registered handler (preventing future re-evaluation), and the catch-up-then-subscribe pattern eliminates gaps between historical replay and live events.","truth_value":"IN","source":"","source_url":"","source_hash":"","justifications":[{"type":"SL","antecedents":["live-projection-idempotent-by-position","live-projection-position-advances-without-handler","catch-up-then-subscribe"],"outlist":[],"label":"Three independent mechanisms collectively enforce exactly-once without distributed coordination"}],"dependents":[],"metadata":{"last_reviewed":"2026-05-30T09:01:17","review_result":"pass"},"created_at":"","updated_at":"","reviewed_at":"","verified_at":"","retracted_at":"","explanation":{"steps":[{"node":"live-projection-exactly-once-via-position-guard","truth_value":"IN","reason":"SL justification valid","antecedents":["live-projection-idempotent-by-position","live-projection-position-advances-without-handler","catch-up-then-subscribe"],"label":"Three independent mechanisms collectively enforce exactly-once without distributed coordination"},{"node":"live-projection-idempotent-by-position","truth_value":"IN","reason":"premise"},{"node":"live-projection-position-advances-without-handler","truth_value":"IN","reason":"premise"},{"node":"catch-up-then-subscribe","truth_value":"IN","reason":"premise"}]}}