T-049: s(12)≥15680/3951=3.9686155…

V3 C3 lower bound confirmed superseded by T-095

2026-08-25 published · Daniel after Burns, Massaccesi · n=12

s(12)≥15680/3951 = 3.9686155..., by Evan Daniel's weighted point certificate, published on 25 August 2026 and first seen here on 27 September. It raised the verified bound by 851/98775, about 0.0086, over T-017.

The certificate is 1,736 D4-invariant rational points of total weight 11.9738036 < 12 such that every closed unit square in [0, 15680/3951]^2, at every angle, captures weight at least one, decided over the rational angle net 2 arctan(k/6000) with a per-bin shrink of 1/(cos d + sin d).

It was replayed here on 27 September 2026 by the source's Rust arrangement-sweep verifier at N=6000, least captured weight 10000056/10^7 at bin 0 as the source records, and by its exact Python re-check on 50 bins. It was also decided completely by this repository's native parent-core interval branch and bound over all 2,486 rows, which shares nothing with the source's sweep and gives the strict s(12)>15680/3951.

Evan Daniel, evand/square-packing (formerly square-packing-12), building on Sam Burns's and Gustavo Massaccesi's weighted exact-rational covering method. The source's CREDITS.md says the work was produced with an AI agent under human direction.

Significance, composition and next rung
Significance
Raised the verified lower bound at n=12 by 0.0086 to within 0.0314 of the grid's 4, on two methods. The method is Burns's and Massaccesi's, as this repository's own n=12 ladder is; the instance is new. A substantive case result, S3. It entered its source ten days before T-017 was scored, which bears on T-017's "first lower bound specific to n=12" (the plan's open question 3) but not on this score.
Composition
Primary at n=12: one certificate, no monotonicity. Two entries whose methods differ decide it, the source's exact arrangement sweep (exact-algebraic, replayed here) and this repository's directed-rounding interval coverage of every row (interval-certified); that is C3, with the two methods shown beside the rung. Both rest on the source's certificate and the same counting theorem, and the thin reader that maps the source's integer file onto parent-core rows has had no review reading of its own.
Next rung
A review reading of the native reader (devtools.verify_evand_angle_net_native) would close the one unread link in the second method's route. V4 and C4 need two adversarial AI reviews by distinct reviewers and a human oversight record, and none is retained; whether a mapped same-project review of another author's result counts toward them is the owner's decision. Rung 5 needs a proof-assistant formalization reviewed by human experts. The exact value remains open; the conjecture is s(12)=4.
Novelty
previously-published Present in an identified source

The case

Case record

n=12

3.974
345
3.4644.464
nn+1

Proven

3.97150≤s(12)≤4

  • exact

Citation record n-012

lowersquarepacker after Daniel, Levy 2026, GitHub (confirmed T-095)

Open

  • optimality

The case record

LowerUpper
Gap572000= 0.0285

Results on the case

10 results in the register on n=12, oldest first, each with what it established and how it stands now.

  1. 2005 published T-007

    s(n)≥min(⌈n⌉,n−2⌊n⌋+1+1) for 4≤n≤324

    V0 C1 lower bound incomplete on this case, superseded by T-095

    Nagamochi · Nagamochi 2005 · source · register

  2. 2026-08-25 published T-049 this result

    s(12)≥15680/3951=3.9686155…

    V3 C3 lower bound confirmed superseded by T-095

    Daniel after Burns, Massaccesi · evand square-packing 2026 · packet · source 1 · source 2 · review 1 · review 2 · register

  3. 2026-09-04 established T-017

    s(12)≥99/25=3.96

    V3 C3 lower bound confirmed superseded by T-095

    Levy after Burns, Massaccesi · register

  4. 2026-09-04 published T-085

    Nagamochi 2005, Lemma 1 is false for every container with a>3 and b>2

    V3 C3 correction confirmed

    Karakuş; chelokot · Karakuş 2026 · chelokot Nagamochi counterexample 2026 · packet · register

  5. 2026-09-29 published T-058

    Rectangle-certificate ceiling α·UB(n) proved for n=1..100; B·UB(n) on 64 grid rows

    V3 C3 method limit confirmed

    wand125 after Tokoharu, Daniel · wand125 tools 2026 · packet · register

  6. 2026-09-29 published T-083

    s(n)≥1/2+n−⌊n⌋+1/4 for every nonsquare 8≤n≤324

    V3 C3 lower bound confirmed on this case, superseded by T-095

    Karakuş · Karakuş 2026 · source · register

  7. 2026-10-02 published T-078

    s(12)≥31360/7901=3.9691178…, Daniel's certificate rescaled by 7902/7901

    V3 C3 lower bound confirmed superseded by T-095

    squarepacker after Daniel · squarepacker s12 2026 · packet · packet · source 1 · source 2 · review 1 · review 2 · register

  8. 2026-10-02 established T-079

    s(12)≥15680000/3949423=3.9702002…, Daniel's points re-weighted

    V3 C3 lower bound confirmed superseded by T-095

    Levy after Daniel · source 1 · source 2 · review · register

  9. 2026-10-05 published T-095

    s(12)≥7943/2000=3.9715, Daniel's points dilated and re-weighted

    V3 C3 lower bound confirmed

    squarepacker after Daniel, Levy · squarepacker s12 2026-10-05 · packet · packet · source 1 · source 2 · review 1 · review 2 · register

  10. 2026-10-07 published T-124

    Reported non-strict local minima for 178 source configurations

    V0 C0 restricted optimality recorded

    Daniel after Couzo · Daniel exact and local reports 2026 · packet · register