n = 82 open ★=
Proven
- new result
- exact
Citation record n-082
lowerwand125 after Tokoharu, Levy et al. 2026, GitHub (confirmed T-076)
upperGöbel 1979, Squares in Squares
Open
- optimality
Bounds
9.53553390593273
- Found by
- Frits Göbel 1979
- Construction
- hand
- Source
- [Kingbird]
- Evidence
E-kingbird-upper-register,E-n082-gobel-l-upper
9.53553390593273762200422181052425
The reported value, verified here.
- Evidence
E-n082-gobel-l-upper
- Proved by
- wand125 2026
- Kind
- counting
- Scope
- Unrestricted unit-square packing with independent rotations and disjoint interiors.
- Note
- wand125's square-packing-bounds (2 October 2026) reports from a measure of 86 point, 222 segment and 774 rectangle orbits of total mass 8199999/100000, at core side 9977/10000 on 201 net half-angles, accepted there at every angle by its linear verifier, code/unified_linear_verify.cpp. It is above Green's reported 9.2667335..., which this case reported before it, and does not rest on Green's argument. Its complete replay here on 3 October 2026 matched the source's run at all 201 directions.
- Source
- [wand125 linear n82 2026-10-02]
- Evidence
E-n082-wand125-linear-932-report
The reported value, verified here.
≈ 0.21553390…
Verified upper minus verified lower.
Results in the register
T-007 V0 C1 Nagamochi · 2026-08-31 · 321 cases
for
T-058 V3 C3 wand125 after Tokoharu, Daniel · 2026-09-29 · 100 cases
Rectangle-certificate ceiling
α·UB(n)proved for ..100;B·UB(n)on 64 grid rowsT-076 V3 C3 wand125 after Tokoharu, Levy, Stromquist, Nagamochi, Burns, Massaccesi · 2026-10-03 · n = 82
Linear-measure lower bound replayed at
Claim and records
- Claim
- A measure of points, segments and rectangles that wand125/square-packing-bounds published on 2 October 2026 proves = 9.32. The measure is of the kind and checker of T-073: point masses, segments of uniform density and rectangles of uniform density, in D4 orbits with exact rational geometry, of total mass 82 - 1/100000, at core side 9977/10000 on 201 net half-angles of step 83/40000, with 86 point, 222 segment and 774 rectangle orbits. They are those of T-073's certificate, every coordinate scaled by exactly 932/935, with the masses solved again.
The source reports it accepted at all 201 net angles, the axis included, by code/unified_linear_verify.cpp, byte for byte the verifier of T-073, in 153,579,479 nodes, and says the full replay was run again from the published tarball by the same implementation. The value exceeds Green's reported 2 sqrt(2) + (247 + 12 sqrt(2))/41 = 9.2667335..., the value this record reported at , by 0.0532664..., and does not rest on Green's argument, which jlevy/squares#308 reports the published material does not establish for k >= 4. Its mass is below 83, where T-075's 937/100 is higher.
It passed a complete replay here on 3 October 2026 of the source's unchanged checker and replay functions on its pinned tarball: all 201 directions, each returning the certificate's own record. The replay runs the source's own algorithm and is not an independent decision of coverage.
wand125 after Tokoharu and Levy, square-packing-bounds. Registration was requested in a comment of 2 October 2026 on jlevy/squares#294. The source says parts of the work were produced with AI assistance under human direction. - Composition
- One claim from one certificate, on its reported entry and its replay entry. The replay runs the source's C++ checker unchanged: one interval-certified method, replayed here, C3. Coverage is decided by that checker alone, which the 2 October review of the linear certificates read function by function.
- Next rung
- V4 and C4 need two adversarial AI reviews by distinct reviewers and a human oversight record; the review of these certificates was the retaining lane's own, and the checker's separately prompted review is T-073's. A second machine method would be a method-distinct decision of rotated coverage for a linear measure; the replay here runs the source's own checker. linear-control n82 would put a negative control on this certificate itself; the checker's controls are 's.
- Significance
- Raised the verified lower bound at from Nagamochi's closed form past Green's reported value, the one count from 82 to 85 where the record still reported Green's value, by a certificate of T-073's kind that does not rest on Green's argument. A further size from one generator and checker, at S3 as T-073 is; the 2 October review of the afternoon certificates proposed S3, which the replay leaves standing. Nagamochi's closed form has been a reported bound since Karakuş's finding (T-085, merged 2026-10-03); on the merged record the verified floor this replay raised at was Karakuş's general bound (T-083), lower still.
- Novelty
- previously-published Present in an identified source
- Records
T-083 V3 C3 Karakuş · 2026-10-02 · 301 cases
for every nonsquare
T-085 V3 C3 Karakuş; chelokot · 2026-10-02 · 315 cases
Nagamochi 2005, Lemma 1 is false for every container with and
upper: replayed here; lower: replayed here
—
not rigid, numerically checked, numerical multiprecision
Evidence: E-translation-escape-not-rigid
Scope
Square 33 of the retained witness (witness id 34) translates 0.535534 along (1, 0) with the packing still valid, so the configuration admits a non-trivial feasible motion; 8 of its 82 squares do. Every constraint is exactly affine in the slide parameter, so the arithmetic carries no linearization error, but the coordinates are the witness's own finite-precision transcription: this settles the retained configuration, not the true optimum. Rigidity and optimality are independent, and this bears only on the former.
- Blocker (source evidence): Green's reported lower-bound proof, cited as private communication by Friedman, has not been recovered or independently replayed.
E-green-ds7-theorem9-reported-lower
9 evidence entries
E-n082-wand125-linear-932-source-replay, E-n082-wand125-linear-932-report, E-kingbird-upper-register, E-nagamochi-lower, E-basic-grid-upper, E-karakus-strip-lower, E-nagamochi-lemma1-counterexample, E-n082-gobel-l-upper, E-green-ds7-theorem9-reported-lower
- [wand125 linear n82 2026-10-02] lower bound proof
- [Kingbird] record catalogue
- [Nagamochi 2005] lower bound proof
- [Friedman DS7] survey
- [Karakuş 2026] lower bound proof
— open
External intake, 2026-10-02 (afternoon). wand125’s linear-certificate source reports (T-076), from a measure of points, segments and rectangles of total mass on the support of its linear certificate scaled by , accepted there at every net angle by the linear verifier the 2 October reviews read with no blocking defect. It is above Green’s reported , the value this case reported before it, by , and does not rest on Green’s argument, which jlevy/squares#308 reports the published material does not establish for . Its complete replay here on 3 October 2026 returned the certificate’s own record at all 201 directions, so it is also the verified lower bound. wand125’s README says parts of the work were produced with AI assistance under human direction.
Open. The best known packing gives , and the verified lower bound is , from wand125’s linear certificate, leaving a gap of .
The packing
Found by Frits Göbel in 1979, via a hand construction: the centred-block family
pose with one L of seventeen unit squares around it, exactly as [Friedman DS7] section
2 states. cases/gobel82 builds it and verifies it exactly over Q(sqrt 2), which is
what moved verified_upper_bound from the grid ceiling onto . The
retained witness declares that side — the exact value correctly rounded up at its
thirty-two digits — but a different layout: its centre set matches none of the
construction’s eight dihedral images, so the certificate is about the construction, not
the witness’s drawing.
The lower bound
Before wand125’s certificate above, the selected external report was [Friedman DS7], which gives the lower-bound expression for (approximately ). Friedman’s DS7 survey, Theorem 9, k=9, reports this bound at n=82; reference [8] is Green’s private communication (2000). The source proof has not been recovered. The unavoidable-set argument DS7’s Figure 34 illustrates does not prove it: at that point pattern leaves a unit square empty (review). That changed the reported source field only; the verified field now holds wand125’s replayed linear certificate. The source audit compares the exact theorem expressions separately from opaque table decimals.
The verified field rests on a complete replay here
(E-n082-wand125-linear-932-source-replay, V3/C3) of wand125’s
linear certificate: the source’s unchanged checker and replay functions on the pinned
bundle, all 201 directions on 3 October 2026, each returning the certificate’s own
record. It runs the source’s own algorithm, so it confirms the source’s run rather than
deciding coverage a second way.
Until 2 October 2026 the verified lower bound was Nagamochi’s general closed form, now a reported bound (see the correction below), and from then until this replay it was Karakuş’s general bound, which applies to every nonsquare :
Correction, 2 October 2026. Until that date the verified lower bound here was Nagamochi’s general closed form, , which is stronger at this and is now recorded as a reported bound. Its published proof rests on Nagamochi’s Lemma 1, which Karakuş showed false; nothing is disproved, and no packing beating it is known (review of 2 October 2026). This register had recorded that proof as verified, its own error, logged as defect D-516.
See the Frontier corpus summary for the current aggregate count; source-reported bounds are recorded separately.
Verification Code
The programs behind this case’s verified bounds, by their evidence.
The code column says how the code that ran stands to the code its producer used.
VERIFIERS.md says what each program is and whose it is.
| bound | evidence | run | code | programs |
|---|---|---|---|---|
| verified lower | E-n082-wand125-linear-932-source-replay |
replayed here | producer’s code | V-wand125-unified-linear-verify-cpp (external); V-audit-wand125-linear (first-party, premises) |
| verified upper | E-n082-gobel-l-upper |
replayed here | independent | V-sqpack-verify (first-party) |