T-078: s(12)≥31360/7901=3.9691178…, Daniel's certificate rescaled by 7902/7901

V3 C3 lower bound confirmed superseded by T-095

2026-10-02 published · squarepacker after Daniel · n=12

s(12)≥31360/7901 = 3.96911783..., by squarepacker (Ryu Sungjoon) after Evan Daniel, published on 2 October 2026 and reported on jlevy/squares#309. It raises the verified bound by 15680/31216851, about 0.000502, over T-049.

The certificate is Daniel's 1,736-point weighted certificate of T-049 with every coordinate and the container multiplied by 7902/7901 and the weights unchanged, total 11.9738036 < 12. The rescaling and its verification on the finer angle net are squarepacker's; the certificate and the verifier that decides it are Daniel's. Every closed unit square in [0, 31360/7901]^2, at every angle, captures weight at least one, decided over the rational angle net 2 arctan(k/24000) with a per-bin shrink of 1/(cos d + sin d). The nets N=6000 and 12000 refuse it, which a pass at one net does not need: each net's test is a complete sufficient condition.

It was replayed here on 2 October 2026 by Daniel's verifier and by squarepacker's own indep_check.cpp at N=24000, least captured weight 10000056/10^7 at bin 0 in both, as the source records, and decided completely by this repository's native parent-core interval branch and bound over all 9,942 rows, which shares nothing with the two sweeps and gives the strict s(12)>31360/7901.

squarepacker (Ryu Sungjoon), s12-lower-bound, archived as Zenodo 10.5281/zenodo.23106582, after Evan Daniel's certificate and verifier (T-049). The source's README says the rescaling, the verification runs and its checker were prepared with the help of an AI assistant from Anthropic, which it names.

Significance, composition and next rung
Significance
True and replayed in full by three checkers, and it raises the verified lower bound at n=12, but by 0.000502, moving the gap to the grid's 4 from 0.0314 to 0.0309. It rescales T-049's certificate until a finer angle net stops accepting it, which spends that certificate's slack and adds no technique, as the source says itself; T-061 is the precedent for scoring such a step by what it changes.
Composition
Primary at n=12: one certificate, no monotonicity. Two entries whose methods differ decide it: the producer's two arrangement sweeps, Daniel's verify and squarepacker's indep_check.cpp (exact-algebraic, replayed here, one method in two implementations), and this repository's directed-rounding interval coverage of every row (interval-certified); that is C3, with the two methods shown beside the rung. All three rest on the certificate, the counting theorem and the shrink lemma on the net N=24000, and the native rows are Daniel's bins and sigma_k by design.
Next rung
V4 and C4 need two adversarial AI reviews by distinct reviewers and a human oversight record; the one retained review was written by the lane that ran the replays, so a separately prompted read is the next step. Rung 5 needs a proof-assistant formalization reviewed by human experts; the source notes that Daniel's Lean pose-box-tree checker, which kernel-checks T-049's certificate, could in principle take this one. 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

    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 this result

    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