{"event":{"id":"evt-hist-20260728-lean-kernel-soundness","dedupe_key":"formal_verification_kernel_security_incident_and_remediation:2026-07-28:lean-maintainers-receive-and-fix-kernel-soundness-flaw-14576-after-invalid-ai-assisted-collatz-disproof","event_type":"formal_verification_kernel_security_incident_and_remediation","title":"Lean maintainers receive and fix kernel soundness flaw #14576 after invalid AI-assisted Collatz disproof","summary":"The Lean 4 soundness flaw in nested inductive-type handling was reduced to a proof of 0 and reported as issue #14576 on 28 July 2026 by Kiran Gopinathan; Lean maintainers pushed fix #14577 within an hour and subsequently merged the fix and released patches. A purported AI-assisted Collatz disproof had appeared July 25 but was invalid, exploiting this kernel bug and an unrelated bug in an outdated nanoda independent checker. The original developer's postmortem was published August 1, after the event. The incident demonstrates a verification-implementation failure, not a mathematical refutation of Collatz or a fundamental inconsistency in Lean's logic.","occurred_at":"2026-07-28T00:00:00.000Z","published_at":"2026-08-01T00:00:00.000Z","observed_at":"2026-10-17T16:16:00.000Z","reconstructed_at":"2026-10-17T16:16:00.000Z","ingest_type":"historical_backfill","locations":null,"status":"verified","confidence":0.96,"metadata":{"external_postcutoff_id":"2026-07-28-lean-kernel-soundness-bug-collatz","event_date_precision":"day","source_publication_date":"2026-08-01","different_prior_incident_date":"2026-07-25","milestone":"bug_report_reproduction_and_patch","evidence_only":1,"new_relation_onset":0,"not_collatz_disproof":1,"not_a_logic_inconsistency":1,"original_source_is_retrospective":1,"canonical_search_exhaustive":0},"created_at":"2026-10-17T17:17:03.347Z","updated_at":"2026-10-17T17:17:03.347Z"},"artifacts":[{"id":"art-hist-20260801-lean-kernel-postmortem","dedupe_key":"91116a2e8389b6dfec403de8914252d23e9e431df9ddfc9d27cab248c8b6f154","canonical_url":"https://leodemoura.github.io/blog/2026-8-1-postmortem-for-kernel-soundness-bug-14576/","evidence_locator":"","artifact_type":"original_developer_reconstruction_of_july_incident","title":"Postmortem for Kernel Soundness Bug #14576","summary":"","creator_entities":[],"released_at":"2026-08-01T00:00:00.000Z","content_hash":null,"metadata":[],"created_at":"2026-10-17T17:17:03.345Z","updated_at":"2026-10-17T17:17:03.345Z","relation":"documented_by"}],"signals":[]}