T-214: Mixed rectangle-measure lower bound s(106)≥10503/1000 reported, on the 201-direction net

V0 C0 Lower bound recorded

2026-10-16 published · Hosono after Tokoharu and Levy · n=106

A rectangle measure of wand125/square-packing, published on 16 October 2026 and reported in jlevy/squares#446, is reported to prove s(106)≥10503/1000 = 10.503.

The certificate, mixed_n106_L10503, is a density of 735 uniform rectangles in D4 orbits, and no point mass, of total mass 10599999/100000, on the net its candidate declares, the standard net of 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 concentric core at a net angle strictly in its interior. The search that found it started from a published certificate at a smaller count, mapped to this side and re-solved by linear programming (lifted, the source's provenance/search-notes.md); the certificate is the measure alone.

The source reports every such core capturing mass at least one at all 201 directions, by sqverify-proof-net, its copy of this repository's sqverify_fast changed to read the declared net, in two complete runs, and a control with every mass scaled by 197/200 refused at 32 sampled directions.

The value is above the reported lower bound at n=106, T-180's 10.403976649170..., Hosono's closed form (jlevy/squares#600), by 0.0990, and above the verified one, 10.3107084351... (Karakuş's strip bound, T-083 and T-084), by 0.1923; the bundle's own README compares it with the latter.

Here the maintained readers accepted its exact mass, declared-net and check2 premises from the retained release asset. No complete replay has run here, so the value stands as reported.

wand125 after Tokoharu and Levy, square-packing. The source says parts of the work were produced with AI assistance under human direction.

Significance, composition and next rung
Significance
Scored as a claim: if a complete replay passes, it is the strongest lower bound on record at n=106, 0.0990 above the reported 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 reported certificate on its reported entry. The source's check is a copy of this repository's sqverify_fast crate with one change, so a sqverify-fast replay here would be re-implemented sharing the producer's components, as T-104's is, and no second implementation stands beside it.
Next rung
C3 needs a complete sqverify-fast census at all 201 directions of the retained candidate, with its whole-net control receipt (the 99/100 mutant at every direction, FC-1) and a review that reads this certificate, by the checklist of the 6 October declared-net soundness review. The census runs in think-f40c, priced at about 0.67 to 0.77 CPU-hours from the source's receipt.
Unfinished confirmations
C3 (think-f40c): a complete sqverify-fast census at all 201 directions of the retained candidate, with its whole-net control receipt (the 99/100 mutant at every direction, FC-1) and a review that reads this certificate, by the checklist of the 6 October declared-net soundness review. About 0.67 CPU-hours, up to about 0.77 (priced 2026-10-17).
Novelty
previously-published Present in an identified source

The case

Case record
Regularized by the Squares Project with Daniel's regularizer (evand/square-packing, MIT)
As published
The packing as published, Couzo 2026 [franciscouzo square-packing 2026-09-27]

n=106

10.3110.823
101112
10.29611.296
nn+1

Proven

10.31070≤s(106)≤10.822909

  • numerical

Citation record n-106

lowerKarakuş 2026, arXiv corrects Nagamochi 2005 (confirmed T-083)

upperCouzo & Daniel, GitHub (confirmed T-098)

Open

  • optimality
  • exact value

The case record

LowerUpper
Gap0.51219960…

Results on the case

8 results in the register on n=106, oldest first, each with what it established and how it stands now.

  1. 2005 published T-007

    s(n)≥min(⌈n⌉,n−2⌊n⌋+1+1) for 4≤n≤324

    V0 C1 Lower bound incomplete on this case, superseded by T-083 and T-180 (reported)

    Nagamochi · Nagamochi 2005 · source · register

  2. 2026-09-04 published T-085

    Nagamochi 2005, Lemma 1 is false for every container with a>3 and b>2

    V3 C3 Correction confirmed

    Karakuş; Vlasenko · Karakuş 2026 · chelokot Nagamochi counterexample 2026 · packet · register

  3. 2026-09-27 published T-056

    Smaller packings for 49 counts from n=68 to 307, each certified two independent ways

    V3 C3 Upper bound confirmed superseded by T-098

    Couzo · franciscouzo square-packing 2026-09-27 · packet · register

  4. 2026-09-29 published T-083

    s(n)≥1/2+n−⌊n⌋+1/4 for every nonsquare 8≤n≤324

    V3 C3 Lower bound confirmed

    Karakuş · Karakuş 2026 · source · register

  5. 2026-10-05 published T-098

    Exact optima of 48 known-best packings: s(n) ≤ S', 3.5e-13 to 5.0e-11 below each printed side

    V3 C3 Upper bound confirmed

    Daniel after Couzo, de Winter, Ellsworth, Levy · evand exact optima 2026-10-05 · packet · register

  6. 2026-10-07 published T-121

    Reported s(106) ≤ alpha_106 with a degree-32 exact side form

    V0 C0 Upper bound recorded

    Daniel after Couzo · Daniel exact and local reports 2026 · packet · register

  7. 2026-10-13 published T-180

    Closed-form lower bound s(N)≥a(N) for every non-square N≥49, reported

    V0 C1 Lower bound reviewed

    Hosono · wand125 closed form 2026-10-14 · packet · packet · register

  8. 2026-10-16 published T-214 this result

    Mixed rectangle-measure lower bound s(106)≥10503/1000 reported, on the 201-direction net

    V0 C0 Lower bound recorded

    Hosono after Tokoharu and Levy · wand125 fine-net lower bounds 2026-10-16 · packet · register