T-075: Mixed rectangle-measure lower bounds replayed at nine counts in
V3 C3 lower bound confirmed
Six rectangle-density certificates that wand125/square-packing-bounds published on the afternoon of 2 October 2026 prove = 9.37, = 9.46, = 9.48, = 9.7, = 9.75 and = 9.96. A packing of 86 squares contains one of 85, and likewise at 88 and 93, so they also give , and .
Each is a density of 279 to 728 uniform rectangles in D4 orbits and no point mass, of total mass n - 1/100000, at core side 9977/10000 on 201 net half-angles of step 83/40000, of the kind and checker of T-069, T-071 and T-072. The source reports each accepted at all 200 oblique net angles by code/mixed_rotated_verify.cpp, its research copy of Tokoharu's verify.cpp at coverage threshold one, and at the axis by exact integer tables. Two supersede certificates this record held verified at the same count, at (T-071) and (T-069).
Each value is above what the record reported at its count: by 0.02 at , over the linear certificate of T-073, and by 0.0025 to 0.095 at the others, over the source's rectangle certificates (T-068, T-074) and its earlier mixed ones. At it is the first certificate in this record above Nagamochi's 1 + sqrt(79) = 9.8882.... At , 85 and 87 the source measures its improvement from 92667/10000, below Green's reported 9.2667335..., so those figures overstate the margin; the bounds are unaffected.
Each certificate passed a complete replay here on 2 and 3 October 2026 of the source's unchanged checker and per-angle functions on its pinned tarball: all 201 directions, each returning the certificate's own record. The replays run the source's own algorithm and are not an independent decision of coverage. sqverify-fast, this repository's clean-room measure verifier, also decided each at all 201 net directions of the retained candidate in its census of 3 October 2026, and on 6 October two mutants of each scaled below coverage one were refused: independently re-implemented, beside the reproduction with the producer's code. It 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.
wand125 after Tokoharu and Levy, square-packing-bounds. Registration was requested in four comments of 2 October 2026 on jlevy/squares#282. The source says parts of the work were produced with AI assistance under human direction.
Significance, composition and next rung
- Significance
- Raised the verified lower bound at nine counts, to 96, the first above Nagamochi's value at . Further sizes from the generator and checker of T-069, T-071 and T-072, with no new technique, at S3 as those are; the 2 October review of the afternoon certificates proposed S3, which the replays leave standing.
- Composition
- Six primary certificates, each on its own reported entry and its own replay entry. , 88 and 93 take the , 87 and 92 certificates directly, their masses being below those counts, so no step is added. Each replay runs the source's C++ checker unchanged: one interval-certified method, replayed here, C3. The axis tables are a second implementation for one direction and not a second method. Each certificate also has a third entry, sqverify-fast at all 201 net directions of the retained candidate: an independent implementation of the same method, recorded beside the rung and not a condition of it.
- Next rung
- V4 and C4 need two adversarial AI reviews by distinct reviewers and a human oversight record; one adversarial review is retained, written by the retaining lane before any replay. A second machine method would be a method-distinct decision of rotated coverage; the replays here, the source's own checker and sqverify-fast, run one method. The source's checker's controls were made on the certificate of the same kind; mixed-control n96 would put one on a certificate of this release. sqverify-fast's controls are on all six.
- Novelty
- previously-published Present in an identified source
The cases
This result concerns 9 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.
| n | Proved lower | Best known | Gap | Status | Records |
|---|---|---|---|---|---|
| 83 | 9.370000 | 9.634758 | 0.26475764… | open= | frontier n-083.md |
| 85 | 9.460000 | 9.742641 | 0.28264068… | frontier n-085.md | |
| 86 | 9.503000 | 9.820566 | 0.31756573… | frontier n-086.md | |
| 87 | 9.580000 | 9.838816 | 0.25881526… | frontier n-087.md | |
| 88 | 9.620000 | 9.882452 | 0.26245103… | frontier n-088.md | |
| 91 | 9.762500 | 10 | 0.2375 | frontier n-091.md | |
| 92 | 9.770000 | 0.23 | frontier n-092.md | ||
| 93 | 9.880000 | 0.12 | frontier n-093.md | ||
| 96 | 9.970000 | 0.03 | frontier n-096.md |
Results on these cases
24 results in the register on these cases, oldest first
2005 published T-007 · 9 of these cases
for
lower bound incomplete on these cases, superseded by T-075, T-081 (reported), T-082, T-090 and T-091
Nagamochi · Nagamochi 2005 · source · register
2026-09-04 published T-085 · 9 of these cases
Nagamochi 2005, Lemma 1 is false for every container with and
correction confirmed
Karakuş; chelokot · Karakuş 2026 · chelokot Nagamochi counterexample 2026 · packet · register
2026-09-24 published T-089 · cases 83, 87
and , 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
2026-09-27 published T-046 · cases 86, 88, 91
Rectangle-density lower bounds reported for 48 counts in
lower bound recorded superseded by T-090 and T-091
wand125 after Tokoharu, Levy, Stromquist, Nagamochi, Burns, Massaccesi · wand125 rectangle bounds 2026 · wand125 rectangle bounds 2026-09-28 · packet · packet · register
2026-09-28 published T-070 · case 86
Rectangle-density lower bounds replayed at 25 counts in
lower bound confirmed superseded by T-090
wand125 after Tokoharu, Levy, Stromquist, Nagamochi, Burns, Massaccesi · wand125 rectangle bounds 2026-09-28 · packet · packet · source · review · register
2026-09-29 published T-058 · 9 of these cases
Rectangle-certificate ceiling
α·UB(n)proved for ..100;B·UB(n)on 64 grid rowsmethod limit confirmed
wand125 after Tokoharu, Daniel · wand125 tools 2026 · packet · register
2026-09-29 published T-083 · 9 of these cases
for every nonsquare
lower bound confirmed on these cases, superseded by T-075, T-081 (reported), T-082, T-090 and T-091
Karakuş · Karakuş 2026 · source · register
2026-10-01 published T-068 · cases 86, 87, 88, 93
Rectangle-density lower bounds verified at 34 counts in
lower bound confirmed on these cases, superseded by T-090 and T-091
wand125 after Tokoharu, Levy, Stromquist, Nagamochi, Burns, Massaccesi · wand125 rectangle bounds 2026-10-01 · packet · source · review · register
2026-10-01 published T-069 · case 92
Mixed rectangle-measure lower bounds replayed at
lower bound confirmed on these cases, superseded by T-082
wand125 after Tokoharu, Levy, Stromquist, Nagamochi, Burns, Massaccesi · wand125 mixed bounds 2026-10-01 · packet · source · review · register
2026-10-01 published T-074 · cases 88, 93
Rectangle-density lower bounds replayed at 31 counts in
lower bound confirmed on these cases, superseded by T-090 and T-091
wand125 after Tokoharu, Levy, Stromquist, Nagamochi, Burns, Massaccesi · wand125 rectangle bounds 2026-10-01 · packet · packet · source · review · register
2026-10-02 published T-071 · cases 85, 86, 87
Mixed rectangle-measure lower bounds replayed at
lower bound confirmed superseded by T-075, T-090 and T-091
wand125 after Tokoharu, Levy, Stromquist, Nagamochi, Burns, Massaccesi · wand125 mixed bounds 2026-10-02 · packet · source · review · register
2026-10-02 published T-073 · case 83
Linear-measure lower bounds replayed at and
lower bound confirmed on these cases, superseded by T-075
wand125 after Tokoharu, Levy, Stromquist, Nagamochi, Burns, Massaccesi · wand125 linear certificates 2026-10-02 · packet · source · review · register
2026-10-02 published T-075 this result · 9 of these cases
Mixed rectangle-measure lower bounds replayed at nine counts in
lower bound confirmed
wand125 after Tokoharu, Levy, Stromquist, Nagamochi, Burns, Massaccesi · wand125 mixed bounds afternoon 2026-10-02 · packet · source 1 · source 2 · review · register
2026-10-03 published T-081 · case 96
for every integer from 5 up; are the cases held here
optimality reviewed
Daniel after Burns, Massaccesi · evand square-packing 2026-10-03 · packet · packet · source · review · register
2026-10-03 published T-082 · 7 of these cases
Mixed rectangle-measure lower bounds verified at 22 counts in
lower bound confirmed
wand125 after Tokoharu, Levy, Stromquist, Nagamochi, Burns, Massaccesi · wand125 mixed bounds 2026-10-03 · packet · packet · source · review · register
2026-10-04 published T-090 · cases 86, 88, 93, 96
Mixed rectangle-measure lower bounds verified at 17 counts in
lower bound confirmed
wand125 after Tokoharu, Levy, Stromquist, Nagamochi, Burns, Massaccesi · wand125 mixed bounds 2026-10-04 · packet · source · review · register
2026-10-04 published T-091 · 5 of these cases
Mixed rectangle-measure lower bounds verified at 17 counts in
lower bound confirmed
wand125 after Tokoharu, Levy, Stromquist, Nagamochi, Burns, Massaccesi · wand125 mixed bounds evening 2026-10-04 · packet · source · review · register
2026-10-05 published T-101 · cases 83, 87, 88
Exact certificates of 77 catalogue packings:
s(n) ≤ S',1.2e-16to9.8e-15above each sideupper bound confirmed
Daniel after Couzo, de Winter, Ellsworth, Levy · evand exact optima 2026-10-05 · packet · register
2026-10-07 published T-116 · case 88
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
2026-10-07 published T-124 · cases 91, 92, 93, 96
Reported non-strict local minima for 178 source configurations
restricted optimality recorded
Daniel after Couzo · Daniel exact and local reports 2026 · packet · register
2026-10-08 published T-125 · cases 86, 88
Complete rational construction reports at 25 counts
upper bound confirmed
ry-xu · ry-xu square packing 2026 · packet · register
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
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
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
Links
- On this site
- The frontier survey · T-075 in the results table
On GitHub, at main
- Register
- T-075 in
results.yaml, line 6984 - Evidence
E-n083-wand125-mixed-937-report·E-n083-wand125-mixed-937-source-replay·E-n083-wand125-mixed-937-sqverify-fast-replay·E-n085-wand125-mixed-946-report·E-n085-wand125-mixed-946-source-replay·E-n085-wand125-mixed-946-sqverify-fast-replay·E-n087-wand125-mixed-948-report·E-n087-wand125-mixed-948-source-replay·E-n087-wand125-mixed-948-sqverify-fast-replay·E-n091-wand125-mixed-970-report·E-n091-wand125-mixed-970-source-replay·E-n091-wand125-mixed-970-sqverify-fast-replay·E-n092-wand125-mixed-975-report·E-n092-wand125-mixed-975-source-replay·E-n092-wand125-mixed-975-sqverify-fast-replay·E-n096-wand125-mixed-996-report·E-n096-wand125-mixed-996-source-replay·E-n096-wand125-mixed-996-sqverify-fast-replay- Proofs and certificates
- certificate
candidate.json.gz· proofcontinuous-density-certificate.ja.md· auditreview-2026-10-02-wand125-afternoon-certificates.md· proofSOUNDNESS.md· certificatecandidate.json.gz· certificatecandidate.json.gz· certificatecandidate.json.gz· certificatecandidate.json.gz· certificatecandidate.json.gz - Sources
- wand125 mixed bounds afternoon 2026-10-02 (its own site, retained copy)
- Source packet
resources/web/wand125-mixed-bounds-afternoon-2026-10-02/README.md- Artifacts
29 artifacts and controls in 14 directories. Complete artifact list in the result entry. docs/project/reviews packing/benchmarks/measure-verifier/census-mixed packing/benchmarks/measure-verifier/census-mixed/wand125-mixed-bounds-afternoon-2026-10-02 packing/devtools packing/resources/web/wand125-mixed-bounds-afternoon-2026-10-02 packing/resources/web/wand125-mixed-bounds-afternoon-2026-10-02/receipts packing/resources/web/wand125-mixed-bounds-afternoon-2026-10-02/receipts/n83 packing/resources/web/wand125-mixed-bounds-afternoon-2026-10-02/receipts/n85-L946 packing/resources/web/wand125-mixed-bounds-afternoon-2026-10-02/receipts/n87 packing/resources/web/wand125-mixed-bounds-afternoon-2026-10-02/receipts/n91 packing/resources/web/wand125-mixed-bounds-afternoon-2026-10-02/receipts/n92-L975 packing/resources/web/wand125-mixed-bounds-afternoon-2026-10-02/receipts/n96 packing/resources/web/wand125-point-and-mixed-2026-10-01/receipts/n37 packing/tests
- Case file
- each case’s file is linked from its row above