T-131: s(132)≤11.987099332245063… from Daniel's record hunt

V3 C3 Upper bound confirmed superseded by T-174

2026-10-09 published · Daniel after Couzo, Chaoweeraprasit, Levy · n=132

One complete rational source certificate by Daniel, reported on jlevy/squares#465, proves a finite upper bound at the exact side it states: s(132)≤11.987099332245063227179742877435.

The certificate gives a rational side and, for each unit square, a rational centre and the tangent of its half-angle. The source checks it with its own verify_cert.py and verify_cert2.py, and reports a different local minimum from the case's, reached from Couzo's packing by an uphill excursion.

All six retained jobs of the release, its n132 and n155 positives with their duplicate-square and outside-container controls, were decided again here on 10 October 2026 by both maintained exact routes and equal their retained rows, and a third exact route, half-extent containment and exact intersection area, decided both certificates with six controls each. No route here is the source's code, so the replay is independently re-implemented. The 10 October review found no blocking defect.

The side was below the case's ceiling, Daniel's exact optimum of Couzo's packing (T-098). On 11 October 2026 the case record adopted the smaller side of issue 489 (T-141) instead, and this certificate stays verified and is not selected.

Credit Daniel (https://github.com/evand/square-packing), from Couzo's packing.

Significance, composition and next rung
Significance
A smaller finite construction side, 4.23e-3 below the case's ceiling; no lower bound or optimum.
Next rung
V4 and C4 need a retained human oversight record: two accepted adversarial reviews by distinct AI reviewers are retained, the 10 October review and the 11 October final review (docs/project/reviews/review-2026-10-11-final-upper-bounds.md). No house move is due: the case at 132 holds issue 489's smaller side (T-141).
Novelty
previously-published Present in an identified source

The case

Case record

n=132

11.5111.986
111213
11.48912.489
nn+1

Proven

11.51135≤s(132)≤11.985681

  • exact

Citation record n-132

lowerKarakuş 2026, arXiv corrects Nagamochi 2005 (confirmed T-083)

upperDaniel & PingYou Ltd, GitHub (confirmed T-174)

Open

  • optimality

The case record

LowerUpper
Gap0.47432242…

Results on the case

12 results in the register on n=132, 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-083 and T-180 (reported)

    Nagamochi · Nagamochi 2005 · source · register

  2. 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; Vlasenko · Karakuş 2026 · chelokot Nagamochi counterexample 2026 · packet · register

  3. 2026-09-27 published T-056

    Smaller packings for 49 counts from n=68 to 307, each certified two independent ways

    V3 C3 Upper bound confirmed superseded by T-174

    Couzo · franciscouzo square-packing 2026-09-27 · packet · register

  4. 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

    Karakuş · Karakuş 2026 · source · register

  5. 2026-10-05 published T-098

    Exact optima of 48 known-best packings: s(n) ≤ S', 3.5e-13 to 5.0e-11 below each printed side

    V3 C3 Upper bound confirmed on this case, superseded by T-174

    Daniel after Couzo, de Winter, Ellsworth, Levy · evand exact optima 2026-10-05 · packet · register

  6. 2026-10-09 published T-131 this result

    s(132)≤11.987099332245063… from Daniel's record hunt

    V3 C3 Upper bound confirmed superseded by T-174

    Daniel after Couzo, Chaoweeraprasit, Levy · Daniel record hunt 2026-10-09 · packet · register

  7. 2026-10-09 published T-134

    Six exact rational certificates from Couzo

    V3 C3 Upper bound confirmed on this case, superseded by T-174

    Couzo after Polkovskyi, Chaoweeraprasit, Gupta, Xu, Daniel, Ellsworth, Levy · Couzo exact certificates 2026-10-09 · packet · register

  8. 2026-10-09 published T-138

    Exact witnesses at Mishapolk's printed ceilings, the smallest known at 103 and 258 when registered

    V3 C3 Upper bound confirmed superseded by T-174

    Polkovskyi after Stenlund, Friedman, Ellsworth, Chaoweeraprasit, Couzo, Xu, Levy · Mishapolk decimal poses 2026-10-09 · packet · register

  9. 2026-10-10 published T-140

    Six more exact rational certificates from Couzo

    V3 C3 Upper bound confirmed superseded by T-174

    Couzo after Chaoweeraprasit, Polkovskyi, Xu, Daniel, Ellsworth, Levy · Couzo certificates 2026-10-10 · packet · register

  10. 2026-10-10 published T-141

    Exact rational certificates at 132 and 308 from Daniel's third record hunt

    V3 C3 Upper bound confirmed superseded by T-174

    Daniel after Fang, Arslanov, Mustafin, Shangitbayev, Couzo, Levy · Daniel record hunt 3 2026-10-10 · packet · register

  11. 2026-10-13 published T-174

    Tighter certificates at 68 counts from PingYou Ltd, of others' packings and its own

    V3 C3 Upper bound confirmed

    PingYou Ltd after Friedman, Ellsworth, Daniel, Xu, Barnett, Couzo, Ostashev, Chaoweeraprasit, Gupta, Fang, Polkovskyi, Levy · PingYou PR 574 certificates 2026-10-13 · packet · register

  12. 2026-10-13 published T-180

    Closed-form lower bound s(N)≥a(N) for every non-square N≥49, reported

    V0 C1 Lower bound reviewed

    Hosono · wand125 closed form 2026-10-14 · packet · packet · register