T-086: s(k2−2)=k for every integer k≥2; k=3…18 are the cases held here

V3 C3 optimality confirmed

2026-09-04 published · chelokot · 16 cases, n=7 to 322

s(k^2 - 2) = k for every integer k >= 2: chelokot's Lean theorem Records.NearSquare.squareMinusTwo_isMinimumSide, kernel-checked here. The lower half compensates each square of score at most one under Nagamochi's measure from other squares of the packing, so it does not use Nagamochi's Lemma 1, which is false (T-085); the upper half is the k x k grid with two squares removed.

This entry's scope is the cases this record holds, k = 3 to 18: s(7)=3, s(14)=4, s(23)=5, s(34)=6, s(47)=7, s(62)=8, s(79)=9, s(98)=10, s(119)=11, s(142)=12, s(167)=13, s(194)=14, s(223)=15, s(254)=16, s(287)=17 and s(322)=18. Nagamochi 2005 stated the family first (T-007).

The development was built here with its pinned toolchain and Mathlib's cache, and its axioms are exactly propext, Classical.choice and Quot.sound. chelokot, square-packing-archive, September 2026.

Significance, composition and next rung
Significance
An infinite family of exact values, proved again after the published proof was found incomplete; every value was already held as proved. S3 by the anchor "a substantive case result or machine audit".
Composition
Compound. The upper half is the grid, E-basic-grid-upper, replayed exactly here; the lower half is E-chelokot-square-minus-two-lean, the source's Lean development rebuilt here with its axiom receipt. A kernel check is machine evidence at rung 3: rung 5 also needs a human expert's review of the formalization, and the statement-fidelity reading retained here is the review lane's.
Next rung
Rung 4 needs two adversarial AI reviews by distinct reviewers and a human oversight record; rung 5 needs a named human expert's review of the formalization, and C5 two, with the open-review pointer the public repository already supports.
Novelty
previously-published Present in an identified source

The cases

This result concerns 16 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.

Results on these cases

6 results in the register on these cases, oldest first
  1. 2005 published T-007 · 16 of these cases

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

    lower bound incomplete

    Nagamochi · Nagamochi 2005 · source · register

  2. 2026-09-04 published T-085 · 15 of these cases

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

    correction confirmed

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

  3. 2026-09-04 published T-086 this result · 16 of these cases

    s(k2−2)=k for every integer k≥2; k=3…18 are the cases held here

    optimality confirmed

    chelokot · chelokot Nagamochi counterexample 2026 · packet · source · register

  4. 2026-09-29 published T-058 · 8 of these cases

    Rectangle-certificate ceiling α·UB(n) proved for n=1..100; B·UB(n) on 64 grid rows

    method limit confirmed

    wand125 after Tokoharu, Daniel · wand125 tools 2026 · packet · register

  5. 2026-09-29 published T-083 · 15 of these cases

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

    lower bound confirmed on these cases, superseded by T-007 (reported) and T-086

    Karakuş · Karakuş 2026 · source · register

  6. 2026-10-07 published T-124 · 16 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