T-250: Hosono reports a Lean kernel proof of Daniel's Valid7, and so of for every
V0 C0 Formalization recorded
Hosono (wand125) reports a Lean 4 kernel proof of Daniel's finite premise Valid7, and with Daniel's reduction a proof that s(k^2 - 3) = k for every integer k >= 6: a formalization of T-064, which this record holds at V3/C3 on two exact checkers of Valid7 and a build here of the reduction. Its theorems, in namespace SquarePacking.LemmaELeaf, are valid7 : Bentz.Valid7, bentz : ∀ k : ℕ, 6 ≤ k → minSide (k ^ 2 - 3) = k, and validTilt7 : Bentz.ValidTilt7.
This entry's scope is that theorem's projection onto the cases this record holds, k = 6 to 18, as T-064's is: , , , , , , , , , , , and .
The proof checks the pose tree of the third k2m3 run on the box cover of L4_k02_box7.txt, one generated module per root cell, 9,800 of them, glued over the D4 root [0, 7/2]^2 x (0, 1/2] in a generated Main.lean, with Bridge.lean identifying the cover with Bentz.box7Cover.
Version 1, merged into Daniel's repository on 11 October, generates the root modules from the per-root certificates of the release data/valid7-lean-certs-v1 and reports a build of roughly 10^4 CPU-hours, later put at about 6,650. Version 2, in wand125/square-packing on 17 October, re-checks the same theorem from the same certificates with re-certified leaves on Daniel's library with a faster row-minimum check, 62,626 generated files, and a recorded run of about 798 CPU-hours. Both report the axioms propext, Classical.choice and Quot.sound, no sorry and no native_decide. Nothing here has built either.
Here the names were audited: the 9,800 pickles of version 1's release asset and version 2's 9,800 root modules are R00000 to R09799, one per root of the run's leaves file, which fills the 35 x grid gen_main.py asserts.
Hosono after Daniel, square-packing and square-packing, 11 and 17 October 2026. Both commits name Claude as co-author.
Significance, composition and next rung
- Significance
- A machine-checked proof, by another author, of the finite premise of a bound family the record holds on two exact checkers and a Lean reduction: with it the whole theorem s(k^2 - 3) = k for every k >= 6 is in Lean, unconditional. A machine audit, S3, below T-064's S4 because it proves no new bound, as T-236 is scored.
- Composition
- Two cited entries, the source's reports of version 1 (E-k2m3-wand125-valid7-lean-v1-report) and version 2 (E-k2m3-wand125-valid7-lean-v2-report), each claiming the exact values in Lean, the grid inside the reduction. T-064's checkers and its reduction build are not cited: they are T-064's evidence. No build is retained here, so V0; no review has read it, so C0.
- Next rung
- C1 needs the stage 4 mathematical review of valid7, Bridge.lean, the glue in gen_main.py and the generators, read from the retained packets. V3 and C3 need a complete build here or by a third party retained here, with the axiom receipt: version 2's is about 798 CPU-hours with 37 GB per leaf module and 51 GB for Main.lean, about 20 times the owner's 40 CPU-hour item cap, and a sample of roots is a component check that moves no rung; which to run, if either, is the owner's decision (think-qu37, #537). Rung 5 needs a human expert's review of the formalization beside it.
- Unfinished confirmations
- C1 (think-0ayk): the stage 4 mathematical review of valid7, bentz and validTilt7, Bridge.lean, the glue of gen_main.py and the generators emit_v7.py and run_v7.py, read from the retained packets. Not priced.
C3 (think-qu37): a complete build of version 2 from its release's generated sources on its library commit, verify.py's checks of every module, Main.lean and Axioms7.lean, with the axiom receipt, here or by a third party whose build is retained here. About 798 CPU-hours (priced 2026-10-26). - Novelty
- previously-published Present in an identified source
The cases
This result concerns 13 cases, too many to draw one by one. Each is listed with the film’s bounds, the proved lower bound and the best known side, and links to its case record, where its packing and number line are drawn.
| n | Proved lower | Best known | Gap | Status | Records |
|---|---|---|---|---|---|
| 33 | 6 | 6 | 0 | provedO= | frontier n-033.md |
| 46 | 7 | 7 | frontier n-046.md | ||
| 61 | 8 | 8 | provedO= | frontier n-061.md | |
| 78 | 9 | 9 | frontier n-078.md | ||
| 97 | 10 | 10 | frontier n-097.md | ||
| 118 | 11 | 11 | frontier n-118.md | ||
| 141 | 12 | 12 | frontier n-141.md | ||
| 166 | 13 | 13 | frontier n-166.md | ||
| 193 | 14 | 14 | frontier n-193.md | ||
| 222 | 15 | 15 | frontier n-222.md | ||
| 253 | 16 | 16 | frontier n-253.md | ||
| 286 | 17 | 17 | frontier n-286.md | ||
| 321 | 18 | 18 | frontier n-321.md |
Results on these cases
16 results in the register on these cases, oldest first
2005 published T-007 · 13 of these cases
for
Lower bound incomplete on these cases, superseded by T-008, T-063, T-064 and T-067
2010-09-13 published T-004 · case 46
Bentz 2010, Theorem 8 () is correct as printed, machine-audited in full
Audit confirmed
Bentz · Bentz 2010 · source · register
2010-09-13 published T-008 · case 46
Optimality confirmed
Bentz · Bentz 2010 · source · register
2018 published T-087 · case 61
and , by optimal piercing
Lower bound reviewed superseded by T-063
2026-09-04 published T-085 · 13 of these cases
Nagamochi 2005, Lemma 1 is false for every container with and
Correction confirmed
Karakuş; Vlasenko · Karakuş 2026 · chelokot Nagamochi counterexample 2026 · packet · register
2026-09-27 published T-045 · cases 61, 78
Rectangle-density lower bounds replayed at 15 counts in
Lower bound confirmed superseded by T-063, T-064 and T-067
Hosono after Tokoharu, Levy, Stromquist, Nagamochi, Burns, Massaccesi · wand125 rectangle bounds 2026 · packet · packet · source · review · register
2026-09-27 published T-046 · cases 61, 78
Rectangle-density lower bounds verified at 48 counts in
Lower bound confirmed superseded by T-063, T-064 and T-067
Hosono after Tokoharu, Levy, Stromquist, Nagamochi, Burns, Massaccesi · wand125 rectangle bounds 2026 · wand125 rectangle bounds 2026-09-28 · packet · packet · source · review · register
2026-09-28 published T-063 · case 61
, by monotonicity from T-062
Optimality confirmed
Daniel after Burns, Massaccesi · evand square-packing 2026-10-01 · packet · packet · packet · source 1 · source 2 · review 1 · review 2 · register
2026-09-29 published T-058 · 5 of these cases
Rectangle-certificate ceiling
α·UB(n)proved for ..100;B·UB(n)on 64 grid rowsMethod limit confirmed
Hosono after Tokoharu, Daniel · wand125 tools 2026 · packet · register
2026-09-29 published T-083 · 13 of these cases
for every nonsquare
Lower bound confirmed on these cases, superseded by T-008, T-063, T-064 and T-067
Karakuş · Karakuş 2026 · source · register
2026-09-30 published T-064 · 13 of these cases
for every integer from 6 up; are the cases held here
Optimality confirmed
Daniel after Burns, Massaccesi · evand square-packing 2026-10-01 · packet · packet · packet · packet · source 1 · source 2 · review 1 · review 2 · register
2026-10-01 published T-067 · case 78
, by a mixed cover extended from Daniel's cover
Optimality confirmed
Hosono after Daniel, Levy, Stromquist, Nagamochi, Burns, Massaccesi · wand125 exact covers 2026-10-01 · packet · source · review · register
2026-10-07 published T-124 · 13 of these cases
Reported non-strict local minima for 178 source configurations
Restricted optimality recorded
Daniel after Couzo · Daniel exact and local reports 2026 · packet · register
2026-10-12 published T-261 · 13 of these cases
Reported grade-C local minima for 233 source configurations of field degree at most 4
Restricted optimality incomplete
Daniel after Schadt, Ellsworth, Levy · Daniel exact and local reports 2026-10-12 · packet · packet · register
2026-10-13 published T-180 · 11 of these cases
Closed-form lower bound for every non-square , reported
Lower bound reviewed on these cases, superseded by T-063, T-064 and T-067
Hosono · wand125 closed form 2026-10-14 · packet · packet · register
2026-10-17 published T-250 this result · 13 of these cases
Hosono reports a Lean kernel proof of Daniel's Valid7, and so of for every
Formalization recorded
Hosono after Daniel, Burns, Massaccesi; Hosono after Daniel, Levy, Burns, Massaccesi · wand125 Valid7 Lean 2026-10-11 · wand125 Valid7 Lean v2 2026-10-17 · packet · packet · source 1 · source 2 · register
Links
- On this site
- Frontier Survey · T-250 in the results table
On GitHub, at main
- Register
- T-250 in
results.yaml, line 35835 - Evidence
E-k2m3-wand125-valid7-lean-v1-report·E-k2m3-wand125-valid7-lean-v2-report- Proofs and certificates
- certificate
Bridge.lean· proofVALID7.md· certificateupstream-subtree.sha256· proofREADME.md - Sources
- wand125 Valid7 Lean 2026-10-11 · wand125 Valid7 Lean v2 2026-10-17
- Source packet
resources/web/evand-valid7-lean-2026-10-11/README.md·resources/web/wand125-valid7-lean-v2-2026-10-17/README.md- Artifacts
11 artifacts and controls
resources/web/evand-valid7-lean-2026-10-11/README.mdresources/web/evand-valid7-lean-2026-10-11/square-packing/lean/VALID7.mdresources/web/evand-valid7-lean-2026-10-11/square-packing/lean/Sqpack/V7/Bridge.leanresources/web/evand-valid7-lean-2026-10-11/square-packing/lean/Sqpack/ValidSplit7.leanresources/web/evand-valid7-lean-2026-10-11/square-packing/lean/scripts/gen_main.pyresources/web/evand-valid7-lean-2026-10-11/receipts/lean-closure.jsonresources/web/evand-valid7-lean-2026-10-11/receipts/root-names.jsonresources/web/wand125-valid7-lean-v2-2026-10-17/README.mddevtools/audit_valid7_roots.pydevtools/lean_closure.pytests/test_audit_valid7_roots.py- Case file
- each case’s file is linked from its row above