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Independent verification: stdlib re-certification of PR1615's eight-transfer threshold, with all 2,502 eight-transfer schedules (only port splits r=1, r=5) (no new kappa) - #1767

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Oct 14, 2026
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Change and mathematical scope

Independent verification. No new κ, and no change to any construction,
certificate, selected record or pinned file.
It adds one registered package,
research/two-connector-eight-transfer-census-seed58/.

Priority belongs to #1615. The six-transfer exclusion and the sharp
eight-transfer threshold for the free-port two-connector family are
#1615 (Hanson Sun / bbMisk). That family is the one from #1438/#1498: five
sources, every B and A called exactly twice, and paid one-way transfers
C: z0 += z1. The eight-transfer word is Discussion #1412 (Cinna Davis).
This package was built concurrently without reading #1615's code. It agrees
with every #1615 number it overlaps.

What it adds:

  1. Re-certification in the generic CI hook. Research: sharp eight-transfer threshold with free source-port choice #1615's registered hook is
    --witness-only, and its exclusion needs a native C++ workflow.
    • Here a gap-reduction lemma lets a pure-Python census certify the
      exhaustive t ≤ 7 exclusion and the exact t = 8 count. On 10 cores it
      takes about 20 s and 50 s, inside the generic Python 3.12 package hook.
    • The lemma: within one gap z1 is fixed. So three transfers act like one
      and four like two, with coverage and restoration parities preserved.
    • Two further code-disjoint engines cross-check it: a full-placement C census
      and a numpy census with per-occurrence ports.
  2. All eight-transfer solutions.
  3. Research: four transfers cannot realize universal two-connector masks #1498's four-transfer split bounds. The r = 2 bound of 25 is not
    attained
    ; the exact maximum is 21. The other bounds are exact, as Research: four transfers cannot realize universal two-connector masks #1498
    itself allowed ("need not be sharp").

Scope. The incidence-minimal 72-call family only. It is a finite census
plus a short reduction lemma. There is no supplier claim. The cost condition is
#1498's t·σ tariff at t = 8, as in #1615.

Task and overlap

Validation

python3 scripts/research_package.py --package research/two-connector-eight-transfer-census-seed58 --check-only
python3.12 scripts/research_package.py --package research/two-connector-eight-transfer-census-seed58

Registered parts (standard library, parallel):

Offline receipts.

  • independent/census.c (every placement, no reduction) agrees exactly:

    t Candidates Restored Universal
    4 30,270,240 10,402,560 0
    6 242,161,920 74,692,800 0
    8 1,323,241,920 384,199,200 2,502

    The t = 6 totals reproduce Research: sharp eight-transfer threshold with free source-port choice #1615.

  • independent/census_numpy.py (per-occurrence ports) gives 74,692,800
    legal schedules and 0 universal at t = 6.

Pre-PR review. A three-lens review covered the mathematics, verifier
soundness and the claims.

  • The math reviewer's own fresh brute force reproduced every count:
    • full-vector, per-occurrence ports for n = 1–3;
    • a full-placement n = 5 C census, including all 2,502 at t = 8, each with
      maximum gap 2;
    • numeric readout equivalence over 92,772 checks.
  • Fixes from the review are included:

Tested on Python 3.12.15 and 3.14.8 (macOS, 10 cores). On a 4-core runner each
part fits well within the 600 s per-command limit.

Credit

AI disclosure: prepared by Sagar Thakrar with substantial Anthropic Claude
assistance, including explorer, judge and reviewer subagents. Two of those
subagents wrote the independent engines. New work is Apache-2.0.

Open next questions

  1. Is there a short structural proof of the six-transfer exclusion that also
    explains why only r = 1 and r = 5 reach eight?
    • First step: classify the 2,502 witnesses by their transfer phases.
    • Blocker: none.
  2. Can extra A/B incidences lower the threshold? This is Research: sharp eight-transfer threshold with free source-port choice #1615's question 1.
    • First step: extend engine.py to 73 calls with full dirt vectors.
    • Blocker: the paired-readout reduction no longer applies.

…er threshold with all 2,502 solutions (no new kappa)

PR1615 (bbMisk) first proved that the PR1438/PR1498 free-port two-connector
family needs exactly eight transfers. This concurrent, code-disjoint package
agrees with every overlapping PR1615 number and adds: a standard-library
certificate of the exclusion and exact count that runs in the generic package
hook (gap-reduction lemma), cross-checked by full-placement C and per-occurrence
numpy engines; the complete eight-transfer solution set (2,502 canonical
schedules, only port splits r=1 with 2,376 and r=5 with 126, all replayed as
80-call programs); and the exact four-transfer split maxima (PR1498's r=2
bound of 25 is not attained; the maximum is 21).

Seed 58, connector-alphabet-change (refined). Prepared with substantial
Anthropic Claude assistance.
@Mister-Meeseeks
Mister-Meeseeks merged commit 4c0bcd5 into CrocSwap:main Oct 14, 2026
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@Mister-Meeseeks

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Batch review at ce50fccd8086bfeb8a61cc9eded572fb4741c387.

Merged to main, preserving the original contributor commits and package attribution.

Reviewed scope: Independent standard-library census reproduces the credited eight-transfer threshold and enumerates2502 canonical schedules, all replayed as80-call programs. Gap-reduction proof and full registered controls/six/eight coverage checked. Separate author C/numpy histories are supporting provenance, not newly replayed here; incidence-minimal one-way-transfer model only.

The pinned scoped command passed; the batch ledger contains its command, input hashes, environment and log. This incorporates the research/tooling contribution and does not change the selected κ or discharge the inherited multiplication-theorem assumptions.

Batch review, attribution and evidence. Thank you for the contribution.

@thakrarsagar
thakrarsagar deleted the research/two-connector-eight-transfer-census-seed58 branch October 14, 2026 19:58
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2 participants