T-220: Daniel's finite sub-grid upper bound for 183 squares, after Couzo's n182 packing
V3 C3 Upper bound confirmed
= 13.999580178736252502081470897571 < 14, from the original rational certificate, printed safely upward as 13.999580178737. Independently re-verified here by the project's maintained exact geometry implementations relative to the producer's code, with complete all-pair/wall coverage and duplicate-square/outside-container controls. Credit Daniel after Couzo's n182 packing, through an explorer descendant, insertion, crossovers and refinement; crossover mates were not logged. The regularized display file is retained source history, unexecuted here.
Significance, composition and next rung
- Significance
- A complete rational certificate gives a sub-grid packing at n183, about 4.20e-4 below the retained side-14 grid. Full exact primary replay and the accepted independent mathematical review support this finite case result; no optimality or public priority is claimed. The review endorses S3.
- Next rung
- Finite feasibility is confirmed by independently re-implemented project geometry, with the common parser/conversion/Fraction/SAT/runtime limits disclosed. No additional primary geometry run is required. The case house was adopted at n183 on 2026-10-19, and both strong generators decided its witness in the same pull request. V4/C4 would require the prescribed accepted distinct reviews and human oversight; regularized/source-checker work is separate and optional for this bound.
- Regularized drawings
- n = 183: a regularization of T-220’s packing by Levy (Daniel's search/regularize (MIT), evand/square-packing@675a5ea, conservative, coincide, through devtools.regularize_evand; the project’s modifications: same-side exact re-solve (devtools.regularize_same_side); at its own side; 1 free angle moved; identity: measured here; nearest centres one to one; 24 squares moved, at most 0.357845; turns up to 6.23142°).
- Novelty
- previously-published Present in an identified source
The case
As published
Proven
- exact
Citation record n-183
lowerKarakuş 2026, arXiv corrects Nagamochi 2005 (confirmed T-083)
upperDaniel 2026, GitHub (confirmed T-220)
Open
- optimality
The case record
Results on the case
6 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V0 C1 Lower bound incomplete on this case, superseded by T-083 and T-180 (reported)
2026-09-04 published T-085
Nagamochi 2005, Lemma 1 is false for every container with and
V3 C3 Correction confirmed
Karakuş; Vlasenko · Karakuş 2026 · chelokot Nagamochi counterexample 2026 · packet · register
2026-09-29 published T-083
for every nonsquare
V3 C3 Lower bound confirmed
Karakuş · Karakuş 2026 · source · register
2026-10-07 published T-124
Reported non-strict local minima for 178 source configurations
V0 C0 Restricted optimality recorded
Daniel after Couzo · Daniel exact and local reports 2026 · packet · register
2026-10-13 published T-180
Closed-form lower bound for every non-square , reported
V0 C1 Lower bound reviewed
Hosono · wand125 closed form 2026-10-14 · packet · packet · register
2026-10-19 published T-220 this result
Daniel's finite sub-grid upper bound for 183 squares, after Couzo's n182 packing
V3 C3 Upper bound confirmed
Daniel after Couzo; register seed data from Levy · Daniel n183 subgrid 2026-10-19 · packet · register
Links
- On this site
- Case record, · Frontier row, · T-220 in the results table
On GitHub, at main
- Register
- T-220 in
results.yaml, line 30156 - Evidence
E-evand-680-n183-report·E-evand-680-n183-primary-exact-feasibility- Proofs and certificates
- certificate
source· certificates183_h183b.cert - Sources
- Daniel n183 subgrid 2026-10-19 (its own site, retained copy)
- Source packet
resources/web/evand-n183-subgrid-2026-10-19/README.md- Artifacts
10 artifacts and controls
resources/web/evand-n183-subgrid-2026-10-19/README.mdresources/web/evand-n183-subgrid-2026-10-19/source/search/packer/candidates/s183_h183b.certresources/web/evand-n183-subgrid-2026-10-19/source/search/packer/candidates/s183_h183b_regularized.certcampaign/issue-intake/intake-followup-20261019/n183-ledger/README.mddocs/project/reviews/review-2026-10-19-evand-n183-subgrid.mdcampaign/issue-intake/intake-followup-20261019/n183-evidence-integration.yamlresources/web/evand-n183-subgrid-2026-10-19/receipts/exact-certification.json.xzresources/web/evand-n183-subgrid-2026-10-19/receipts/certify-execution-provenance.jsontests/test_upper_bound_reports.pyresources/web/evand-n183-subgrid-2026-10-19/receipts/exact-certification.json.xz- Case file
frontier/n-183.md(verified lower, verified upper, reported lower, reported upper)