mrwulf 3700ed8a90 paper: Fable-5 rigor re-audit of the depth pass — fix 3 real defects ...

Re-auditing the prior (Opus-produced) depth pass adversarially found and
fixed three genuine issues:

1. OVERCLAIM (serious): §5.3 said the consistency verifier was
   differential-tested 'on all (n0,n1) with n1<=256' but the script only
   SAMPLED sizes (5,508 cases). Ran the genuinely exhaustive test — all
   1<=n0<=n1<=256, honest + 4 mutations — 164,224 invocations, and the
   inclusion verifier likewise (164,479). Paper now states the true scope
   and counts; both are pinned in a new CI test (test_paper_verifiers.py,
   104 tests) so the numbers cannot rot.
2. PROOF IMPRECISION: Lemma 2 (Root binding) was applied to ConsRec's
   first component, which PASSES THROUGH (no hnode) at some levels and so
   is not the hash-fold the lemma needs. Reworked: Lemma 2 now defined
   over 'hash-folds' only; Theorem 3 restructured into 3 clean steps that
   put only the full-hashing second component through the lemma, then
   argue algebraically + one honest-tree collision. Also hoisted Lemma 2
   above Theorem 2 and made Theorem 2 invoke it (was inlined), so the
   'two theorems share the lemma' remark is now true; deduped the remark.
3. MISLABELED TABLE: Table 1's 'files vs upstream' column actually held
   line-diffs against different baselines. Dropped it for clean comparable
   columns (files / apex axioms / SHA-512 shape); the diff story stays in
   the portability paragraph where each baseline is named.

17 pages, all refs resolve, 104 tests green.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

2026-07-09 19:46:11 +02:00

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