T-229: Polkovskyi's re-solves of the house packings at 105 and 204, below T-174 and T-225

V0 C0 Upper bound recorded

2026-10-22 published · Polkovskyi after Couzo, Muglich, Daniel, Xu, PingYou Ltd, Levy · n=105,204

Two complete rational source certificates of issue 719 report finite upper-bound improvements at the exact sides they state: s(105)≤674331486483935962030285457609/62500000000000000000000000000 and s(204)≤882663895519250432/59604644775390625, below the case's house best packing at each, T-174 at 105 by 5.18e-12 and T-225 at 204 by 1.006e-8. Complete native feasibility outcomes are retained separately; the case lanes are unchanged until the entry is reviewed and adopted, so it is pending adoption at both counts.

The issue states that every certificate passes Daniel's exact checker verify_cert.py and this repository's sqpack/verify.py with zero tolerance, 122 of 122 on each, run from the author's own copies, which are not in the pinned tree. Those statements are the author's; no source program ran here.

Credit the packings to their finders, each re-solved to a smaller side by Polkovskyi (https://github.com/Mishapolk/square-packing-records), the name the record gives him since issue 593 (the issue gives Mikhail Polk): at 105 Xu's packing as Couzo and PingYou Ltd refined it (T-174); at 204 Couzo's packing (#678, T-223) as Daniel regularized it (T-225), which Couzo's source credits to Polkovskyi's own construction (hop job 105412). The source states no method and no lineage per count; the issue credits Mishapolk (Mikhail Polk) and names the earlier finders its packings build on, and discloses Gemini assistance.

Significance, composition and next rung
Significance
Re-solves of the house packings at 105 and 204 to smaller exact sides. At 105 the side is 5.18e-12 below T-174, a padding-scale re-solve of the packing T-174 refines, S1 as T-174's and T-186's are; at 204 it is 1.006e-8 below T-225, with one square re-oriented, more than T-225's own 1.39e-9 below T-223, S2 as T-225 is. One entry takes the higher: a citable detail of each case that moves no theorem. No lower bound or optimum.
Next rung
Independently review the retained replay at 105 and 204 (think-4h23); after that review the house rule adopts both and the regularization layer decides them, lapsing 105's grid-slack view and SETTLED[204]. The 111 rows beyond the corpus are the source's dated beyond-horizon rows since 22 October 2026, recorded in report order by the ledger of 22 October for issue 719 (upper-bounds-issue719-20261022).
Unfinished confirmations
C3 (think-4h23): Review the retained two-route replay of #719's 105 and 204 certificates and enter it as confirming evidence, then adopt both and regularize them. About 0.5 CPU-hours, up to about 1 (priced 2026-10-22).
Regularizations
n = 105: a regularization of T-174’s packing by Polkovskyi (exact re-solve (the source states no method); solved to its side; identity: measured here; nearest centres one to one; 42 squares moved, at most 0.049; turns up to 2.411°).

n = 204: a regularization of T-225’s packing by Polkovskyi (exact re-solve (the source states no method); solved to its side; identity: measured here; nearest centres one to one; 67 squares moved, at most 0.273; turns up to 25.64°).
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, Xu 2026 [PingYou PR 574 certificates 2026-10-13]

n=105

10.2810.789
101112
10.24711.247
nn+1

Proven

10.28000≤s(105)≤10.789304

  • exact

Citation record n-105

lowerHosono after Tokoharu, Levy et al. 2026 (confirmed T-073, T-080)

upperXu et al., GitHub (confirmed T-174)

Open

  • optimality

The case record

LowerUpper
Gap0.50930378…
Case record

n=204

14.2914.809
141516
14.28315.283
nn+1

Proven

14.29311≤s(204)≤14.808643

  • exact

Citation record n-204

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

upperCouzo & Daniel, GitHub (confirmed T-225)

Open

  • optimality

The case record

LowerUpper
Gap0.51552861…

Results on these cases

25 results in the register on n=105,204, oldest first, each with what it established and how it stands now.

  1. 2005 published T-007 · n=105,204

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

    V0 C1 Lower bound incomplete on these cases, superseded by T-073, T-080, T-083 and T-180 (reported)

    Nagamochi · Nagamochi 2005 · source · register

  2. 2026-09-04 published T-085 · n=105,204

    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 · n=105

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

    V3 C3 Upper bound confirmed superseded by T-174

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

  4. 2026-09-29 published T-083 · n=105,204

    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. 2026-10-02 published T-073 · n=105

    Linear-measure lower bounds replayed at n=83 and n=101…105

    V3 C3 Lower bound confirmed

    Hosono after Tokoharu, Levy, Stromquist, Nagamochi, Burns, Massaccesi · wand125 linear certificates 2026-10-02 · packet · source · review · register

  6. 2026-10-02 published T-080 · n=105

    Linear-measure lower bound replayed at n=101…105

    V3 C3 Lower bound confirmed

    Hosono after Tokoharu, Levy, Stromquist, Nagamochi, Burns, Massaccesi · wand125 linear certificates 2026-10-02 · packet · source · review · register

  7. 2026-10-05 published T-101 · n=204

    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

  8. 2026-10-07 published T-117 · n=105

    Exact rational ceiling refinements at n=105, 292

    V3 C3 Upper bound confirmed superseded by T-174

    Rehwaldt after Couzo and earlier contributors · Rehwaldt Couzo refinements 2026-10-07 · packet · register

  9. 2026-10-07 published T-129 · n=105

    Three dated Daniel certificate reports with historical source custody

    V0 C0 Upper bound recorded superseded by T-174

    Daniel after Couzo, Levy · Daniel dated certificates 105 and 130 2026-10-07 · Daniel dated certificate 292 2026-10-07 · packet · packet · packet · register

  10. 2026-10-08 published T-125 · n=105

    Complete rational construction reports at 25 counts

    V3 C3 Upper bound confirmed superseded by T-174

    Xu · ry-xu square packing 2026 · packet · register

  11. 2026-10-08 published T-128 · n=105

    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

  12. 2026-10-08 published T-130 · n=105

    Five follow-up rational refinements from Couzo

    V3 C3 Upper bound confirmed superseded by T-174

    Couzo after Xu, Daniel, Ellsworth, Levy · Couzo follow-up refinements 2026-10-08 · packet · register

  13. 2026-10-09 published T-138 · n=105

    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

  14. 2026-10-12 established T-155 · n=204

    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

  15. 2026-10-12 published T-162 · n=204

    New packings of 129, 204 and 303 squares, a cut-out and two compositions, each certified exactly

    V3 C3 Upper bound confirmed superseded by T-225

    Ostashev after Nakajima, Chaoweeraprasit, Daniel, Xu, Levy · Ostashev compositions 2026-10-12 · packet · register

  16. 2026-10-12 published T-170 · n=105

    An exact contact refinement of Xu's packing of 105 squares, after Couzo's

    V3 C3 Upper bound confirmed superseded by T-174

    PingYou Ltd after Xu, Couzo, Daniel, Levy · PingYou n105 refinement 2026-10-12 · packet · register

  17. 2026-10-13 published T-174 · n=105,204

    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

  18. 2026-10-13 published T-180 · n=105,204

    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

  19. 2026-10-14 published T-186 · n=204

    Exact certificates at twelve counts from Polkovskyi, tightening the smallest reported there

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

    Polkovskyi after Ostashev, Couzo, PingYou Ltd, Levy · Mishapolk KKT refinements 2026-10-14 · packet · register

  20. 2026-10-16 published T-193 · n=204

    Exact algebraic sides at sixteen counts from Daniel, of packings the record credits

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

    Daniel after Xu, Chaoweeraprasit, Ostashev, Couzo, PingYou Ltd, Gupta, Polkovskyi, Levy · Daniel exact current records 2026-10-16 · packet · register

  21. 2026-10-17 published T-226 · n=204

    Couzo's 204 of #670, below Polkovskyi's T-186, since superseded by his own #675 and #678

    V0 C0 Upper bound recorded superseded by T-225

    Couzo after Polkovskyi, Daniel, Levy · Couzo issue 670 2026-10-17 · packet · packet · register

  22. 2026-10-18 published T-223 · n=204

    Couzo's smaller packings at 204 and 260, the two in the corpus of issue 678's 85 bounds

    V3 C3 Upper bound confirmed superseded by T-225

    Couzo after de Winter, Polkovskyi, Daniel, Fang, PingYou Ltd, Levy · Couzo issue 678 2026-10-18 · packet · register

  23. 2026-10-18 published T-228 · n=204

    Couzo's 204 of #675, below his #670, since superseded by his #678

    V0 C0 Upper bound recorded superseded by T-225

    Couzo after Polkovskyi, Daniel, Levy · Couzo issue 675 2026-10-18 · packet · packet · register

  24. 2026-10-20 published T-225 · n=204

    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

  25. 2026-10-22 published T-229 this result · n=105,204

    Polkovskyi's re-solves of the house packings at 105 and 204, below T-174 and T-225

    V0 C0 Upper bound recorded

    Polkovskyi after Couzo, Muglich, Daniel, Xu, PingYou Ltd, Levy · Mishapolk issue 719 2026-10-22 · packet · register