T-108: Mixed rectangle-measure lower bound verified at n=29, on a declared net

V3 C3 lower bound confirmed

2026-10-06 published · wand125 after Tokoharu, Levy, Stromquist, Nagamochi, Burns, Massaccesi · n=29

A rectangle density of wand125/square-packing-bounds, checked at coverage one on a net it declares and published on 6 October 2026, proves s(29)≥581/100 = 5.81.

The certificate is a density of 505 uniform rectangles in D4 orbits, and no point mass, of total mass 2899999/100000, on the net T-096's certificate declares: core side 999/1000 and 416 half-angle tangents of step 1/1001. Since 999/1000 (1 + 1/1001) = 500499/500500 < 1, and the last tangent 415/1001 is past tan(pi/8), every unit square contains a concentric core at a net angle strictly in its interior.

The source reports every such core capturing mass at least one: at all 415 oblique net angles by code/mixed_rotated_verify.cpp, its research copy of Tokoharu's verify.cpp at coverage threshold one, run by the same driver as T-096's certificate, and at the axis by exact integer tables.

The value is above 2319/400 = 5.7975, the source's rectangle certificate rect_n29_L57975 and the reported (T-068) and verified (T-074) lower bound at n=29 before it, by 0.0125.

The certificate was decided here on 6 October 2026 by sqverify-fast, this repository's clean-room measure verifier, at all 416 directions of the net the candidate declares, and two mutants scaled below coverage one were refused: confirmed, independently re-implemented. The verifier shares no code with the source's checker and runs the same net-and-shrink method, so it is a second implementation and not a second method. The source's own checker was replayed here at nodes 0, 1, 364 and 415, the axis and the least-bound node among them, each returning the certificate's own record, and not in full: a partial reproduction with the producer's code.

wand125 after Tokoharu and Levy, square-packing-bounds. No registration was requested: an intake pass of the source found it. The source says parts of the work were produced with AI assistance under human direction.

Significance, composition and next rung
Significance
The strongest verified lower bound on record at n=29, by 0.0125 above T-074, and the strongest reported. The certificate kind of T-099 on a declared net with the C++ checker of T-069 and later; no new technique, at S3 as T-096, T-099 and T-100 are.
Composition
One primary certificate on its reported entry and its replay entry. The replay is sqverify-fast at all 416 directions of the net the retained candidate declares: one interval-certified method, replayed here by an independent implementation, C3, on the census route. The source's checker was replayed at sampled directions and its axis tables at the axis only, so no second method and no complete reproduction with the producer's code stands beside it.
Next rung
V4 and C4 need two adversarial AI reviews of this result by distinct reviewers and a human oversight record; one is retained. A complete replay of the source's own checker, the bundle's driver over all 416 nodes (42 CPU-hours by the source's own seconds, about 30 at the sample's rate here), would add a reproduction with the producer's code beside the rung.
Novelty
previously-published Present in an identified source

The case

Case record

n=29

5.815.934
567
5.3856.385
nn+1

Proven

5.81000≤s(29)≤5.933834

  • numerical

Citation record n-029

lowerwand125 after Tokoharu, Levy et al. 2026, GitHub (confirmed T-108)

upperSchadt & Ellsworth, Squares in Squares (reported)

Open

  • optimality
  • exact value

The case record

LowerUpper
Gap0.12383346…

Results on the case

13 results in the register on n=29, 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-108

    Nagamochi · Nagamochi 2005 · source · register

  2. 2026-08-29 established T-009

    s(29)≤5.933833…, by a Krawczyk interval certificate

    V3 C3 upper bound confirmed

    Levy · register

  3. 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

  4. 2026-09-22 published T-044

    Weighted point lower bounds for ten counts in n=26…72, plus seven from the same files

    V3 C3 lower bound confirmed superseded by T-108

    wand125 after Levy, Stromquist, Nagamochi, Burns, Massaccesi · wand125 point bounds 2026 · packet · source · review · register

  5. 2026-09-22 published T-047

    s(11)≥381/100; s(n)≥1377/250 for n=26…28; s(n)≥571/100 for n=29…31

    V3 C3 lower bound confirmed superseded by T-108

    Tokoharu after Levy, wand125, Stromquist, Nagamochi, Burns, Massaccesi · Tokoharu density 2026 · packet · source · review · register

  6. 2026-09-27 published T-046

    Rectangle-density lower bounds reported for 48 counts in n=18…95

    V0 C0 lower bound recorded superseded by T-108

    wand125 after Tokoharu, Levy, Stromquist, Nagamochi, Burns, Massaccesi · wand125 rectangle bounds 2026 · wand125 rectangle bounds 2026-09-28 · packet · packet · register

  7. 2026-09-28 published T-070

    Rectangle-density lower bounds replayed at 25 counts in n=29…95

    V3 C3 lower bound confirmed superseded by T-108

    wand125 after Tokoharu, Levy, Stromquist, Nagamochi, Burns, Massaccesi · wand125 rectangle bounds 2026-09-28 · packet · packet · source · review · register

  8. 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

  9. 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-108

    Karakuş · Karakuş 2026 · source · register

  10. 2026-10-01 published T-068

    Rectangle-density lower bounds verified at 34 counts in n=19…95

    V3 C3 lower bound confirmed on this case, superseded by T-108

    wand125 after Tokoharu, Levy, Stromquist, Nagamochi, Burns, Massaccesi · wand125 rectangle bounds 2026-10-01 · packet · source · review · register

  11. 2026-10-01 published T-074

    Rectangle-density lower bounds replayed at 31 counts in n=19…95

    V3 C3 lower bound confirmed on this case, superseded by T-108

    wand125 after Tokoharu, Levy, Stromquist, Nagamochi, Burns, Massaccesi · wand125 rectangle bounds 2026-10-01 · packet · packet · source · review · register

  12. 2026-10-06 published T-108 this result

    Mixed rectangle-measure lower bound verified at n=29, on a declared net

    V3 C3 lower bound confirmed

    wand125 after Tokoharu, Levy, Stromquist, Nagamochi, Burns, Massaccesi · wand125 mixed bounds check2 2026-10-06 · packet · source · review · register

  13. 2026-10-10 published T-132

    Mixed rectangle-measure lower bound s(29)≥291/50 reported, on a 2,073-direction declared net

    V0 C0 lower bound recorded

    wand125 after Tokoharu and Levy · wand125 fine-net n29 2026-10-10 · packet · register