T-227: Couzo's refinements of de Winter's 227 and 229, below T-196 at both

V0 C0 Upper bound recorded superseded by T-225

2026-10-17 published · Couzo after de Winter, Daniel, Levy · n=227,229

Two complete rational source certificates report finite upper-bound improvements at the exact sides they state: s(227)≤71427829379429597600111901507/4589408083628500000000000000 and s(229)≤231170315041711399213831561/14771101209934000000000000. Complete native feasibility outcomes are retained separately; the entry awaits independent review. At 227 it is below de Winter's T-196, the house best packing when it was reported; Daniel's solved view of this packing (T-225), smaller still, has been the house since 22 October 2026. At 229 Daniel's #674 opening and update (T-198, T-199), reported after it, are smaller.

The issue states that each bound is strictly smaller than the source's previous published index and a reviewed comparison envelope including deletion and repeated L borders, and the manifest records the author's checker receipts with the source's exact checker verify_bound_certificate.py (Daniel's MIT verifier, modified by Couzo with Codex), pinned here by digest and not run. Those statements are the author's; no source program ran here.

Credit Couzo (https://github.com/franciscouzo/square-packing) with refinements of de Winter's #668 packings (T-196), as the author's comment of 17 October says: at 227 a CT105 web submission (method fq) seeded from de Winter's #668 certificate by way of Daniel's exact form of it, which the source does not say who made, and at 229 an slp refinement (search job 106640) of de Winter's #668 certificate.

Significance, composition and next rung
Significance
Refinements of de Winter's 227 and 229 packings (T-196), the same arrangement solved lower by 1.71e-4 at 227 and 1.67e-8 at 229: a citable step that moves no theorem, S2 as T-199 (a same-arrangement step of 1.32e-5) and T-225, whose rationale already gives the 1.71e-4 at 227 to this report. No lower bound or optimum.
Next rung
Independently review the retained replay (think-0nse). At 227 the entry is 1.71e-4 below T-196, the house when it was reported, and Daniel's solved view of this packing (T-225), 1.76e-11 below it, has been the house since 22 October 2026; at 229 it is superseded on entry by #674's opening and update (T-198, T-199), reported after it, T-199 1.32e-5 below it. The 44 rows beyond the corpus are the source's dated beyond-horizon rows since 22 October 2026, recorded in report order by the backlog ledger (upper-bounds-backlog-20261022).
Unfinished confirmations
C3 (think-0nse): Review the retained two-route replay of #672's 227 and 229 certificates and enter it as confirming evidence, with sharp controls at 1e-30. Not priced.
Regularizations
n = 227: a regularization of T-196’s packing by Couzo (fq refinement, a CT105 web submission (f0ca7a65) seeded from de Winter's #668 certificate by way of Daniel's exact form; solved to its side; identity: the source’s claim; nearest centres one to one; 59 squares moved, at most 0.0796; turns up to 5.842°).

n = 229: a regularization of T-196’s packing by Couzo (slp refinement (search job 106640) of de Winter's #668 certificate; solved to its side; identity: the source’s claim; nearest centres one to one; 57 squares moved, at most 0.00941; turns up to 0.0308°).
Novelty
previously-published Present in an identified source

The cases

Case record
Regularized by the Squares Project with Daniel's regularizer (evand/square-packing, MIT)
As published
The packing as published, de Winter 2026 [Daniel regularized lists 2026-10-20]

n=227

15.0615.564
151617
15.06716.067
nn+1

Proven

15.06880≤s(227)≤15.563626

  • exact

Citation record n-227

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

upperde Winter et al., GitHub (confirmed T-225)

Open

  • optimality

The case record

Case record
Regularized by the Squares Project with Daniel's regularizer (evand/square-packing, MIT)
As published
The packing as published, Daniel 2026 [Daniel regularized lists 2026-10-20]

n=229

15.1315.650
151617
15.13316.133
nn+1

Proven

15.13728≤s(229)≤15.650162

  • exact

Citation record n-229

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

upperDaniel 2026, GitHub (confirmed T-225)

Open

  • optimality

The case record

Results on these cases

11 results in the register on n=227,229, oldest first, each with what it established and how it stands now.

  1. 2005 published T-007 · n=227,229

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

    V0 C1 Lower bound incomplete on these cases, superseded by T-083

    Nagamochi · Nagamochi 2005 · source · register

  2. 2026-09-04 published T-085 · n=227,229

    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. 2026-09-29 published T-083 · n=227,229

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

    V3 C3 Lower bound confirmed

    Karakuş · Karakuş 2026 · source · register

  4. 2026-10-05 published T-101 · n=227,229

    Exact certificates of 77 catalogue packings: s(n) ≤ S', 1.2e-16 to 9.8e-15 above each side

    V3 C3 Upper bound confirmed on these cases, superseded by T-225

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

  5. 2026-10-12 established T-155 · n=227,229

    Exact regularized sides at 59 counts, 5.4e-20 to 9.9e-15 below the ceilings they replace

    V3 C3 Upper bound confirmed on these cases, superseded by T-225

    Levy after Daniel · register

  6. 2026-10-13 published T-180 · n=227,229

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

    V0 C1 Lower bound reviewed on these cases, superseded by T-083

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

  7. 2026-10-17 published T-196 · n=227,229

    de Winter reports three smaller rational upper bounds at 227, 229 and 260

    V3 C3 Upper bound confirmed superseded by T-225

    de Winter after Levy · de Winter upper bounds 2026-10-17 · packet · register

  8. 2026-10-17 published T-198 · n=229

    Daniel's opening n229 dilation certificate, after Couzo and de Winter

    V3 C3 Upper bound confirmed superseded by T-225

    Daniel after Couzo, de Winter, Levy · Daniel n229 dilation 2026-10-17 · packet · register

  9. 2026-10-17 published T-227 this result · n=227,229

    Couzo's refinements of de Winter's 227 and 229, below T-196 at both

    V0 C0 Upper bound recorded superseded by T-225

    Couzo after de Winter, Daniel, Levy · Couzo issue 672 2026-10-17 · packet · packet · register

  10. 2026-10-18 published T-199 · n=229

    Daniel's smaller n229 update, replacing the opening certificate

    V3 C3 Upper bound confirmed superseded by T-225

    Daniel after Couzo, de Winter, Levy · Daniel n229 dilation update 2026-10-18 · packet · register

  11. 2026-10-20 published T-225 · n=227,229

    Daniel's solved, regularized views at 204, 227, 229 and 260, each the smallest side reported there

    V3 C3 Upper bound confirmed

    Daniel after Couzo, de Winter, Polkovskyi, Levy · Daniel regularized lists 2026-10-20 · packet · register