T-216: Mixed rectangle-measure lower bound verified, on the 201-direction net
V3 C3 Lower bound confirmed
A rectangle measure of wand125/square-packing, published on 16 October 2026 and reported in jlevy/squares#446, proves = 10.62.
The certificate, mixed_n108_L1062, is a density of 823 uniform rectangles in D4 orbits, and no point mass, of total mass 10799999/100000 < 108. Its declared net has 201 half-angle tangents of step 83/40000 at core side 9977/10000. Since 9977/10000 (1 + 83/40000) = 399908091/400000000 < 1, and the last tangent 83/200 is past tan(pi/8), every unit square contains a closed concentric core at a net angle strictly inside its interior. The search started from a published certificate at a smaller count, mapped to this side and re-solved by linear programming; lifting describes the search, not a premise of the proof.
The maintained sqverify-fast census decided the retained candidate at all 201 directions, with summary VERIFIED and return code 0. Its whole-net control receipt records CONTROLS_REFUSED: the 99/100 mass mutant is refused at every direction, and the near-threshold mutant is refused at the least-bound leaf. The exact premise and saved-point audit recomputed all 201 refusal witnesses and their original captures. Two separately prompted mathematical reviews accepted the certificate's implication and exact premises; the second used the strongest tier at maximum reasoning required by the import runbook. The audits read the retained complete replay; they did not rerun the native engine.
The verified lower lane rises from 10.4121138007... (Karakuş's strip bound, T-083 and T-084) to 10.62, and the reported lane from T-180's closed form, 10.484093855851..., to the same value. The bound is confirmed by a re-implementation sharing the producer's components. The producer's sqverify-proof-net is a copy of this repository's sqverify_fast crate with its declared-net reader changed, so agreement supplies no independent full implementation or second method and establishes no optimality.
wand125 after Tokoharu and Levy, square-packing. The source reports AI assistance under human direction.
Significance, composition and next rung
- Significance
- The strongest verified and reported lower bound on record at , 0.1359 above the previous reported lane and 0.2079 above the verified lane, by the certificate kind and standard net of T-082, T-090 and T-091, with no new technique, at S3 as T-176 to T-178 are.
- Composition
- One primary certificate on its source-report and maintained-replay entries. The full replay uses sqverify-fast at all 201 directions of the retained candidate's declared net: one interval-certified method, sharing the producer's sqverify_fast components, C3. The separate standard-library audits check exact premises and saved poses; neither decides coverage between those poses, supplies an independent full implementation, or adds a second method.
- Next rung
- V4 and C4 require a human oversight record alongside the two retained adversarial AI reviews. A full implementation that shares no producer code would add independent full confirmation; the exact point audits do not provide that. The other 17 fine-net imports remain under think-f40c.
- Novelty
- previously-published Present in an identified source
The case
Proven
- exact
Citation record n-108
lowerHosono after Tokoharu and Levy 2026, GitHub (confirmed T-216)
upperXu et al., GitHub (confirmed T-174)
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-216
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 on this case, superseded by T-216
Karakuş · Karakuş 2026 · source · 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 on this case, superseded by T-174
Daniel after Couzo, de Winter, Ellsworth, Levy · evand exact optima 2026-10-05 · packet · register
2026-10-07 published T-113
at ten counts, to 303, from new SQUISH rational packings
V3 C3 Upper bound confirmed superseded by T-174
Chaoweeraprasit after Ellsworth · SQUISH ten packings 2026-10-07 · packet · register
2026-10-07 published T-116
at nine counts, from the second SQUISH update’s new rational packings
V3 C3 Upper bound confirmed superseded by T-174
Chaoweeraprasit after Ellsworth, Couzo and SQUISH · SQUISH second update 2026-10-07 · packet · register
2026-10-08 published T-125
Complete rational construction reports at 25 counts
V3 C3 Upper bound confirmed superseded by T-174
2026-10-08 published T-127
Fourteen rational refinements, seventeen complete source cases
V3 C3 Upper bound confirmed on this case, superseded by T-174
Gupta after Chaoweeraprasit, Daniel · Gupta rational refinements 2026-10-08 · packet · register
2026-10-08 published T-128
Eight complete rational refinements from Couzo
V3 C3 Upper bound confirmed superseded by T-174
Couzo after Xu, Chaoweeraprasit, Gupta, Ellsworth, Daniel, Levy · Couzo exact refinements 2026-10-08 · packet · register
2026-10-09 published T-138
Exact witnesses at Mishapolk's printed ceilings, the smallest known at 103 and 258 when registered
V3 C3 Upper bound confirmed superseded by T-174
Polkovskyi after Stenlund, Friedman, Ellsworth, Chaoweeraprasit, Couzo, Xu, Levy · Mishapolk decimal poses 2026-10-09 · packet · register
2026-10-13 published T-174
Tighter certificates at 68 counts from PingYou Ltd, of others' packings and its own
V3 C3 Upper bound confirmed
PingYou Ltd after Friedman, Ellsworth, Daniel, Xu, Barnett, Couzo, Ostashev, Chaoweeraprasit, Gupta, Fang, Polkovskyi, Levy · PingYou PR 574 certificates 2026-10-13 · packet · register
2026-10-13 published T-180
Closed-form lower bound for every non-square , reported
V0 C1 Lower bound reviewed on this case, superseded by T-216
Hosono · wand125 closed form 2026-10-14 · packet · packet · register
2026-10-16 published T-216 this result
Mixed rectangle-measure lower bound verified, on the 201-direction net
V3 C3 Lower bound confirmed
Hosono after Tokoharu and Levy · wand125 fine-net lower bounds 2026-10-16 · packet · source · review · register
Links
- On this site
- Case record, · Frontier row, · T-216 in the results table
On GitHub, at main
- Register
- T-216 in
results.yaml, line 29686 - Evidence
E-wand125-fine-net-n108-1062-report·E-wand125-fine-net-n108-1062-sqverify-fast-replay·E-n108-review-max-premises·E-n108-review-max-captures- Proofs and certificates
- certificate
candidate.json.gz· proofSOUNDNESS.md· auditreview-2026-10-18-n108-fine-net-mathematics-max.md· certificateaudit.json - Sources
- wand125 fine-net lower bounds 2026-10-16 (its own site, retained copy)
- Source packet
resources/web/wand125-fine-net-lower-bounds-2026-10-16/README.md- Artifacts
20 artifacts and controls
resources/web/wand125-fine-net-lower-bounds-2026-10-16/README.mdresources/web/wand125-fine-net-lower-bounds-2026-10-16/acquisition/sources.jsonresources/web/wand125-fine-net-lower-bounds-2026-10-16/acquisition/release-assets.jsonresources/web/wand125-fine-net-lower-bounds-2026-10-16/release/certificates/mixed_n108_L1062/candidate.json.gzresources/web/wand125-fine-net-lower-bounds-2026-10-16/release/certificates/mixed_n108_L1062/check2/receipt.jsonresources/web/wand125-fine-net-lower-bounds-2026-10-16/receipts/premises-n108.jsondevtools/fine_net_followup.pydocs/project/reviews/review-2026-10-18-wand125-n108-certificate-mathematics.mddocs/project/reviews/review-2026-10-18-n108-fine-net-mathematics-max.mdresources/web/wand125-fine-net-lower-bounds-2026-10-16/review/n108-exact-audit.jsondevtools/audit_fine_net_receipt.pysqverify_fast/SOUNDNESS.mdbenchmarks/measure-verifier/census-mixed/census.jsonbenchmarks/measure-verifier/census-mixed/wand125-fine-net-lower-bounds-2026-10-16/mixed_n108_L1062.jsonl.gzresources/web/wand125-fine-net-lower-bounds-2026-10-16/review-max/README.mdresources/web/wand125-fine-net-lower-bounds-2026-10-16/review-max/n108_audit.pyresources/web/wand125-fine-net-lower-bounds-2026-10-16/review-max/audit.jsonbenchmarks/measure-verifier/census-mixed/wand125-fine-net-lower-bounds-2026-10-16/mixed_n108_L1062.control.jsontests/test_sqverify_fast_census.pytests/test_audit_fine_net_receipt.py- Case file
frontier/n-108.md(verified lower, verified upper, reported lower, reported upper)