T-068: Rectangle-density lower bounds verified at 34 counts in n=19…95

V3 C3 lower bound confirmed

2026-10-01 published · wand125 after Tokoharu, Levy, Stromquist, Nagamochi, Burns, Massaccesi · 34 cases, n=19 to 95

Thirty-four rectangle-density certificates of wand125/square-packing-bounds, one at each of 34 counts from n=19 to n=95, published between 29 September and 1 October 2026, prove the values below. They raise 32 of the values T-046 reports and add n=87 and n=93.

Up to n=44 the values are s(19)≥1927/400, s(20)≥1959/400, s(26)≥2213/400, s(27)≥1127/200, s(28)≥2289/400, s(29)≥2319/400, s(30)≥47/8, s(31)≥2381/400, s(38)≥1309/200, s(39)≥1327/200, s(40)≥67/10, s(41)≥169/25, s(42)≥1363/200, s(43)≥551/80 and s(44)≥2777/400.

From n=53 they are s(53)≥3043/400, s(54)≥3069/400, s(55)≥617/80, s(56)≥3113/400, s(66)≥1677/200, s(68)≥851/100, s(69)≥1717/200, s(70)≥69/8, s(74)≥3539/400, s(75)≥89/10, s(76)≥357/40, s(86)≥1873/200, s(87)≥941/100, s(88)≥3791/400, s(89)≥1913/200, s(90)≥3831/400, s(93)≥3889/400, s(94)≥1961/200 and s(95)≥49259/5000.

Each is an exact nonnegative rational density on rectangles, D4-expanded, of mass n - 1/100, at core side 9977/10000 on 201 net half-angles of step 83/40000, built with Tokoharu's solver, its weights scaled to that mass. The source reports each accepted at all 201 net directions by Tokoharu's unchanged interval checker, verify.cpp, and replayed in full from its published files on a second machine before publication.

Each certificate was decided here by sqverify-fast, this repository's clean-room measure verifier, at all 201 net directions of the retained candidate at Tokoharu's threshold 10001/10000, in the census of 3 October 2026, and on 6 October two mutants of each scaled below that threshold 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.

Thirty of the certificates, all but n=66, 86, 87 and 90, were also replayed here in full with the source's own checker on 2 October, each reproducing the upstream accepting run at every direction; 29 of them are registered again in T-074, and n=76's in none. The case records decide which certificate is current at each count.

wand125 after Tokoharu and Levy, square-packing-bounds. Registration was requested in jlevy/squares#281. The source says parts of the work were produced with AI assistance under human direction.

Significance, composition and next rung
Significance
The strongest rectangle-density lower bounds on record at 34 counts when published, each above the certificate T-046 reports there; through T-074's replays, 29 of them raised the verified lower bound. Further sizes and raised rungs from one generator at S3. The 2 October review of these certificates confirmed S3.
Composition
One claim per count, each on its own certificate at one source revision, the packet's reported entry and its own replay entry. Each replay is sqverify-fast at all 201 net directions of the retained candidate: one interval-certified method, replayed here by an independent implementation, C3, on the census route for format T that the review of 6 October set and these certificates meet. The source's checker was also replayed here on 30 of them, a reproduction with the producer's code beside the rung, recorded in the packet's receipts and, for 29, under T-074; no second method stands beside it.
Next rung
V4 and C4 need two adversarial AI reviews of this result by distinct reviewers and a human oversight record: the 2 October review of these certificates is one, and the 6 October review of the format T census route decided the route, not these certificates' mathematics. A complete replay of the source's own checker on the four certificates it has not run on, rect_n66_L8385, rect_n86_L9365, rect_n87_L941 and rect_n90_L95775 (10.7 CPU-hours by the upstream per-angle times), would add a reproduction with the producer's code beside the rung for those counts; a second machine method would be a method-distinct decision of rotated coverage.
Novelty
previously-published Present in an identified source

The cases

This result concerns 34 cases, too many to draw one by one. Each is listed with the film’s bounds, the proved lower bound and the best known side, and links to its case record, where its packing and number line are drawn.

nProved lowerBest knownGapStatusRecords
194.8250004.8856190.06061808…open=frontier n-019.md
204.90500050.095frontier n-020.md
265.5450005.6213210.07632034…frontier n-026.md
275.6435005.7071070.06360678…frontier n-027.md
285.7350005.8244450.08944461…open=Rfrontier n-028.md
295.8100005.9338340.12383346…open≈frontier n-029.md
305.88350060.1165open=frontier n-030.md
315.9525000.0475frontier n-031.md
386.5450006.7071070.16210678…frontier n-038.md
396.6500006.8107230.16072208…frontier n-039.md
406.7158156.8284280.11261137…open=Rfrontier n-040.md
416.7750006.9266940.15169309…open=frontier n-041.md
426.84750070.1525frontier n-042.md
436.9075000.0925frontier n-043.md
446.9725000.0275frontier n-044.md
537.6275007.8228760.19537565…frontier n-053.md
547.6850007.8466680.16166719…frontier n-054.md
557.7280007.9457720.21777100…open≈frontier n-055.md
567.80250080.1975open=frontier n-056.md
668.4300008.6568550.22685424…frontier n-066.md
688.5100008.7987960.28879523…frontier n-068.md
698.6200008.8271950.20719465…frontier n-069.md
708.6575008.8809610.22346037…frontier n-070.md
748.86750090.1325frontier n-074.md
758.9400000.06frontier n-075.md
768.9650000.035frontier n-076.md
869.5030009.8205660.31756573…frontier n-086.md
879.5800009.8388160.25881526…frontier n-087.md
889.6200009.8824520.26245103…frontier n-088.md
899.6500009.9497480.29974746…frontier n-089.md
909.730000100.27frontier n-090.md
939.8800000.12frontier n-093.md
949.9500000.05frontier n-094.md
959.9650000.035frontier n-095.md

Results on these cases

55 results in the register on these cases, oldest first
  1. 2005 published T-007 · 34 of these cases

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

    lower bound incomplete on these cases, superseded by T-068, T-074, T-082, T-090, T-091, T-097, T-103, T-104, T-105, T-106, T-107, T-108, T-109, T-110, T-111 and T-145

    Nagamochi · Nagamochi 2005 · source · register

  2. 2026-08-21 published T-016 · case 19

    s(n)≥22529/5000 for n=18,19, by monotonicity from T-015

    lower bound confirmed superseded by T-103

    Massaccesi after Burns · Burns–Massaccesi n17 · packet · register

  3. 2026-08-29 established T-009 · case 29

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

    upper bound confirmed

    Levy · register

  4. 2026-08-30 established T-013 · case 40

    Goebel's n=40 packing: seven verified first-order flexes, each refused at second order

    rigidity confirmed

    Levy · register

  5. 2026-09-04 established T-019 · case 19

    s(n)≥459/100=4.59 for n=17,18,19

    lower bound confirmed superseded by T-103

    Levy after Burns, Massaccesi · register

  6. 2026-09-04 established T-020 · cases 19, 20

    s(n)≥24/5=4.80 for n=19,20,21

    lower bound confirmed superseded by T-103 and T-104

    Levy after Burns, Massaccesi · register

  7. 2026-09-04 published T-085 · 34 of these cases

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

    correction confirmed

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

  8. 2026-09-05 established T-021 · case 20

    s(n)≥97/20=4.85 for n=20,21

    lower bound confirmed superseded by T-104

    Levy after Burns, Massaccesi · register

  9. 2026-09-22 published T-044 · 12 of these cases

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

    lower bound confirmed superseded by T-068, T-074, T-082, T-090, T-091, T-105, T-108, T-110, T-111 and T-145

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

  10. 2026-09-22 published T-047 · 6 of these cases

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

    lower bound confirmed superseded by T-068, T-074, T-105, T-106, T-107, T-108 and T-109

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

  11. 2026-09-24 published T-088 · case 69

    s(69)≤8.82719465572975, Ellsworth's degree-38 packing, certified exactly from its picture

    upper bound confirmed superseded by T-101

    Ellsworth after hmbelvedere, Cantrell, Schadt, Morandi · Ellsworth n69 2026-09-24 · packet · packet · register

  12. 2026-09-24 published T-089 · case 87

    s(83)≤9.63475764863195 and s(87)≤9.83881526994915, Chang's packings, certified exactly

    upper bound confirmed superseded by T-101

    Chang, Ellsworth after Cantrell, Hajba, Stenlund, Bidwell; Chang after Ellsworth, Cantrell, Schadt, Hajba, DeVincentis · Chang n83 2026-09-24 · Chang n87 2026-09-24 · packet · packet · register

  13. 2026-09-27 published T-045 · 10 of these cases

    Rectangle-density lower bounds replayed at 15 counts in n=18…78

    lower bound confirmed superseded by T-068, T-074, T-090, T-091, T-103, T-104, T-105, T-106, T-107, T-109 and T-145

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

  14. 2026-09-27 published T-046 · 32 of these cases

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

    lower bound recorded superseded by T-068, T-074, T-082, T-090, T-091, T-097, T-103, T-104, T-105, T-106, T-107, T-108, T-109, T-110, T-111 and T-145

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

  15. 2026-09-27 published T-056 · case 68

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

    upper bound confirmed superseded by T-118

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

  16. 2026-09-28 published T-070 · 16 of these cases

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

    lower bound confirmed superseded by T-068, T-074, T-082, T-090, T-091, T-108, T-110 and T-111

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

  17. 2026-09-29 published T-058 · 34 of these cases

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

    method limit confirmed

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

  18. 2026-09-29 published T-083 · 34 of these cases

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

    lower bound confirmed on these cases, superseded by T-068, T-074, T-082, T-090, T-091, T-097, T-103, T-104, T-105, T-106, T-107, T-108, T-109, T-110, T-111 and T-145

    Karakuş · Karakuş 2026 · source · register

  19. 2026-10-01 published T-068 this result · 34 of these cases

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

    lower bound confirmed

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

  20. 2026-10-01 published T-069 · cases 66, 90

    Mixed rectangle-measure lower bounds replayed at n=37,65,66,90,92

    lower bound confirmed on these cases, superseded by T-091 and T-097

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

  21. 2026-10-01 published T-074 · 29 of these cases

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

    lower bound confirmed

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

  22. 2026-10-02 published T-071 · cases 86, 87

    Mixed rectangle-measure lower bounds replayed at n=84…87

    lower bound confirmed superseded by T-090 and T-091

    wand125 after Tokoharu, Levy, Stromquist, Nagamochi, Burns, Massaccesi · wand125 mixed bounds 2026-10-02 · packet · source · review · register

  23. 2026-10-02 published T-072 · case 76

    Mixed rectangle-measure lower bound replayed at n=76

    lower bound confirmed superseded by T-091

    wand125 after Tokoharu, Levy, Stromquist, Nagamochi, Burns, Massaccesi · wand125 mixed bounds n76 2026-10-02 · packet · packet · source · review · register

  24. 2026-10-02 published T-075 · cases 86, 87, 88, 93

    Mixed rectangle-measure lower bounds replayed at nine counts in n=83…96

    lower bound confirmed on these cases, superseded by T-090 and T-091

    wand125 after Tokoharu, Levy, Stromquist, Nagamochi, Burns, Massaccesi · wand125 mixed bounds afternoon 2026-10-02 · packet · source 1 · source 2 · review · register

  25. 2026-10-02 published T-077 · cases 20, 42, 70

    Rectangle-density lower bounds replayed at n=20, 42 and 70

    lower bound confirmed superseded by T-090, T-091 and T-104

    wand125 after Tokoharu, Levy, Stromquist, Nagamochi, Burns, Massaccesi · wand125 rectangle bounds 2026-10-02 · packet · packet · source 1 · source 2 · review 1 · review 2 · register

  26. 2026-10-03 published T-082 · 14 of these cases

    Mixed rectangle-measure lower bounds verified at 22 counts in n=51…96

    lower bound confirmed

    wand125 after Tokoharu, Levy, Stromquist, Nagamochi, Burns, Massaccesi · wand125 mixed bounds 2026-10-03 · packet · packet · source · review · register

  27. 2026-10-04 published T-090 · 11 of these cases

    Mixed rectangle-measure lower bounds verified at 17 counts in n=42…96

    lower bound confirmed

    wand125 after Tokoharu, Levy, Stromquist, Nagamochi, Burns, Massaccesi · wand125 mixed bounds 2026-10-04 · packet · source · review · register

  28. 2026-10-04 published T-091 · 11 of these cases

    Mixed rectangle-measure lower bounds verified at 17 counts in n=53…95

    lower bound confirmed

    wand125 after Tokoharu, Levy, Stromquist, Nagamochi, Burns, Massaccesi · wand125 mixed bounds evening 2026-10-04 · packet · source · review · register

  29. 2026-10-05 published T-097 · case 66

    Mixed rectangle-measure lower bound verified at n=66

    lower bound confirmed

    wand125 after Tokoharu, Levy, Stromquist, Nagamochi, Burns, Massaccesi · wand125 mixed bounds finer net 2026-10-05 · packet · source · review · register

  30. 2026-10-05 published T-098 · case 68

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

    upper bound confirmed on these cases, superseded by T-118

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

  31. 2026-10-05 published T-101 · 10 of these cases

    Exact certificates of 77 catalogue packings: s(n) ≤ S', 1.2e-16 to 9.8e-15 above each side

    upper bound confirmed

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

  32. 2026-10-06 published T-100 · case 19

    Mixed rectangle-measure lower bound verified at n=19, past the best 18-square packing

    lower bound confirmed superseded by T-103

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

  33. 2026-10-06 published T-103 · case 19

    Mixed rectangle-measure lower bound verified at n=19, on the finest declared net yet

    lower bound confirmed

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

  34. 2026-10-06 published T-104 · case 20

    Mixed rectangle-measure lower bound verified at n=20, on a declared net

    lower bound confirmed

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

  35. 2026-10-06 published T-105 · case 26

    Mixed rectangle-measure lower bound verified at n=26, on a declared net

    lower bound confirmed

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

  36. 2026-10-06 published T-106 · case 27

    Mixed rectangle-measure lower bound verified at n=27, on a declared net

    lower bound confirmed

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

  37. 2026-10-06 published T-107 · case 28

    Mixed rectangle-measure lower bound verified at n=28, on a declared net

    lower bound confirmed

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

  38. 2026-10-06 published T-108 · case 29

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

    lower bound confirmed

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

  39. 2026-10-06 published T-109 · case 30

    Mixed rectangle-measure lower bound verified at n=30, on a declared net

    lower bound confirmed

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

  40. 2026-10-06 published T-110 · case 39

    Mixed rectangle-measure lower bound verified at n=39, on a declared net

    lower bound confirmed

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

  41. 2026-10-06 published T-111 · case 41

    Mixed rectangle-measure lower bound verified at n=41, on a declared net

    lower bound confirmed

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

  42. 2026-10-07 published T-116 · case 88

    s(n)≤Sn at nine counts, from the second SQUISH update’s new rational packings

    upper bound confirmed on these cases, superseded by T-127

    Chaoweeraprasit after Ellsworth, Couzo and SQUISH · SQUISH second update 2026-10-07 · packet · register

  43. 2026-10-07 published T-118 · case 68

    Exact rational ceiling refinements at n=68

    upper bound confirmed

    Rehwaldt after Couzo and earlier contributors · Rehwaldt n68 refinement 2026-10-07 · packet · register

  44. 2026-10-07 published T-124 · 15 of these cases

    Reported non-strict local minima for 178 source configurations

    restricted optimality recorded

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

  45. 2026-10-08 published T-125 · cases 70, 86, 88

    Complete rational construction reports at 25 counts

    upper bound confirmed

    ry-xu · ry-xu square packing 2026 · packet · register

  46. 2026-10-08 published T-127 · case 88

    Fourteen rational refinements, seventeen complete source cases

    upper bound confirmed

    Gupta after Chaoweeraprasit, Daniel · Gupta rational refinements 2026-10-08 · packet · register

  47. 2026-10-08 published T-130 · case 86

    Five follow-up rational refinements from Francisco Couzo

    upper bound confirmed

    Couzo after Xu, Daniel, Ellsworth, Levy · Couzo follow-up refinements 2026-10-08 · packet · register

  48. 2026-10-09 published T-138 · case 86

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

    upper bound confirmed

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

  49. 2026-10-10 published T-132 · case 29

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

    lower bound recorded

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

  50. 2026-10-10 published T-133 · case 40

    s(40)>335427/50000=6.70854, by a clipped-corner transfer on a 401-direction net

    lower bound confirmed superseded by T-145

    Guzhou0806 after wand125, Tokoharu, Levy, Stromquist, Burns, Massaccesi · Guzhou0806 n40 clipped corner 2026-10-10 · packet · packet · source 1 · source 2 · review · register

  51. 2026-10-10 published T-137 · case 70

    An exact rational refinement of Ryan Xu's packing of 70 squares

    upper bound confirmed

    Deleeuw after Xu, Levy · Deleeuw n70 refinement 2026-10-10 · packet · register

  52. 2026-10-10 published T-142 · case 28

    Mixed rectangle-measure lower bound s(28)≥2297/400 reported, on a 2,073-direction declared net

    lower bound recorded

    wand125 after Tokoharu and Levy · wand125 fine-net n28 n30 2026-10-10 · packet · register

  53. 2026-10-10 published T-143 · case 30

    Mixed rectangle-measure lower bound s(30)≥2357/400 reported, on a 2,073-direction declared net

    lower bound recorded

    wand125 after Tokoharu and Levy · wand125 fine-net n28 n30 2026-10-10 · packet · register

  54. 2026-10-10 published T-145 · case 40

    s(40)>1340000/199529=6.7158157…, by a continuous-pose interval kernel

    lower bound confirmed

    Guzhou0806 after wand125, Tokoharu, Levy, Stromquist, Burns, Massaccesi · Guzhou0806 n40 continuous pose 2026-10-10 · packet · packet · source 1 · source 2 · review · register

  55. 2026-10-10 published T-146 · case 70

    Exact rational certificates at fifteen counts from Evan Daniel's regularized record lists

    upper bound confirmed

    Daniel after Xu, Chaoweeraprasit, Mishapolk, Levy · Daniel regularized lists 2026-10-10 · packet · register