T-088: , Ellsworth's degree-38 packing, certified exactly from its picture
V3 C3 upper bound confirmed superseded by T-101
, by David Ellsworth's packing of 69 unit squares, certified here exactly. The Kingbird catalogue prints the packing's side as 8.82719465572973, cut short from 8.827194655729738914..., the root near it of the degree-38 polynomial the catalogue prints; neither of those two is certified here.
In the catalogue's words, the packing was "Refound by David Ellsworth in September 2026, using his modified version of Thomas Schadt's simulated annealing program, starting from found by Maurizio Morandi in June 2010", and "Optimized by David Ellsworth in September 2026". It is the packing whose side hmbelvedere's UnitSquare release reported in July 2026 as 8.8272055078..., which the catalogue lists as "Improved by hmbelvedere in July 2026, using an undisclosed iterative method (probably with AI)", after David W. Cantrell's improvement of August 2023; the optimization lowers that side by about 1.1e-5.
The catalogue states no checker, and its picture, which holds the pose, could not be fetched. The certificate is a third party's binary64 parse of that picture, rounded to rationals and dilated about its centre by 1 + 1e-15: an exact rational packing of side 8.8271946557297478..., 1.8e-14 above the printed side, decided pair by pair and wall by wall over Q by two checkers of this repository that share no geometry or verification code, and refused by both when its side is cut by 1e-15 or one square is moved by 1e-6. The bound above is that side rounded up at the printed precision.
David Ellsworth, September 2026, in the Squares in Squares catalogue.
Significance, composition and next rung
- Significance
- Lowers the best known side at one count by about 1.1e-5, by optimizing a packing already reported. S2 by the anchor "a citable detail that changes no theorem".
- Next rung
- V4 and C4 need two adversarial AI reviews by distinct reviewers of the claim and a human oversight record; the review of 2026-10-05 is one. The verified bound sat 2e-14 above the printed side because the certificate is a binary64 parse; the pose refined on its active contacts, Evan Daniel's exact certificate (T-101), has since brought the case's verified upper bound within one unit of the printed side's last place. A method-distinct second route is what C4 needs.
- Novelty
- previously-published Present in an identified source
The case
Proven
- exact
Citation record n-069
lowerwand125 after Tokoharu, Levy et al. 2026, GitHub (confirmed T-090)
upperMorandi et al., Squares in Squares (confirmed T-101)
Open
- optimality
The case record
Results on the case
13 results in the register on , oldest first, each with what it established and how it stands now.
2005 published T-007
for
V0 C1 lower bound incomplete on this case, superseded by T-090
Nagamochi · Nagamochi 2005 · source · register
2026-09-04 published T-085
Nagamochi 2005, Lemma 1 is false for every container with and
V3 C3 correction confirmed
Karakuş; chelokot · Karakuş 2026 · chelokot Nagamochi counterexample 2026 · packet · register
2026-09-22 published T-044
Weighted point lower bounds for ten counts in , plus seven from the same files
V3 C3 lower bound confirmed superseded by T-090
wand125 after Levy, Stromquist, Nagamochi, Burns, Massaccesi · wand125 point bounds 2026 · packet · source · review · register
2026-09-24 published T-088 this result
, Ellsworth's degree-38 packing, certified exactly from its picture
V3 C3 upper bound confirmed superseded by T-101
Ellsworth after hmbelvedere, Cantrell, Schadt, Morandi · Ellsworth n69 2026-09-24 · packet · packet · register
2026-09-27 published T-046
Rectangle-density lower bounds reported for 48 counts in
V0 C0 lower bound recorded superseded by T-090
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
Rectangle-density lower bounds replayed at 25 counts in
V3 C3 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
Rectangle-certificate ceiling
α·UB(n)proved for ..100;B·UB(n)on 64 grid rowsV3 C3 method limit confirmed
wand125 after Tokoharu, Daniel · wand125 tools 2026 · packet · register
2026-09-29 published T-083
for every nonsquare
V3 C3 lower bound confirmed on this case, superseded by T-090
Karakuş · Karakuş 2026 · source · register
2026-10-01 published T-068
Rectangle-density lower bounds verified at 34 counts in
V3 C3 lower bound confirmed on this case, superseded by T-090
wand125 after Tokoharu, Levy, Stromquist, Nagamochi, Burns, Massaccesi · wand125 rectangle bounds 2026-10-01 · packet · source · review · register
2026-10-01 published T-074
Rectangle-density lower bounds replayed at 31 counts in
V3 C3 lower bound confirmed on this case, superseded by T-090
wand125 after Tokoharu, Levy, Stromquist, Nagamochi, Burns, Massaccesi · wand125 rectangle bounds 2026-10-01 · packet · packet · source · review · register
2026-10-03 published T-082
Mixed rectangle-measure lower bounds verified at 22 counts in
V3 C3 lower bound confirmed on this case, superseded by T-090
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
Mixed rectangle-measure lower bounds verified at 17 counts in
V3 C3 lower bound confirmed
wand125 after Tokoharu, Levy, Stromquist, Nagamochi, Burns, Massaccesi · wand125 mixed bounds 2026-10-04 · packet · source · review · register
2026-10-05 published T-101
Exact certificates of 77 catalogue packings:
s(n) ≤ S',1.2e-16to9.8e-15above each sideV3 C3 upper bound confirmed
Daniel after Couzo, de Winter, Ellsworth, Levy · evand exact optima 2026-10-05 · packet · register
Links
- On this site
- Case record, · Frontier row, · T-088 in the results table
On GitHub, at main
- Register
- T-088 in
results.yaml, line 8492 - Evidence
E-n069-ellsworth-2026-09-report·E-n069-ellsworth-2026-09-exact-replay- Proofs and certificates
- certificate
n-069-rational.yaml - Sources
- Ellsworth n69 2026-09-24
- Source packet
resources/web/kingbird-squares-in-squares.md·resources/web/known-best-packings/README.md- Artifacts
11 artifacts and controls
resources/web/kingbird-squares-in-squares.mdwitnesses/known-best/n-069.yamldevtools/derive_kingbird_facts.pydevtools/catalogue_upper_bounds.pydevtools/check_rational_witness_independent.pywitnesses/kingbird-2026/n-069-rational.yamlresources/web/known-best-packings/README.mdresources/web/known-best-packings/receipts/kingbird-2026-09-certification.jsondocs/project/reviews/review-2026-10-05-kingbird-intake-n69-n83-n87.mdresources/web/known-best-packings/receipts/kingbird-2026-09-negative-controls.jsontests/test_catalogue_upper_bounds.py- Case file
frontier/n-069.md(verified lower, verified upper, reported lower, reported upper)