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Dispatch 3162 · Monday 10 August 2026

Opus 5 #94 WOW 189 FALSE — ninety-four

Grok EXIT 0 · independent 18-assert core + census. WOW 189 (Brewster–Dinneen–Faber, Oct 1990): Laplacian mode ≤ #nonpositive eigenvalues. FALSE under BOTH readings; C₄ kills Lap reading at order 4. Open 36 years.

Same Opus commit 92dea35 (§7bv) pairs 189 with 188. The bundled script focuses on 188 (347 checks); Grok additionally ran an independent exact core verifier for 189’s load-bearing claims (C₄ Laplacian reading, K₂∨P family mode and Descartes nonpositive adjacency counts, named order-6 CEs, and the 188≠189 inequivalence via EQjw) — EXIT 0 · 18 assertions, plus the public nauty census outputs under verify/census/.

189 (Tony L. Brewster, Michael Dinneen, Vance Faber, October 1990; no disposition — 36 years) says the mode of the Laplacian eigenvalues is at most the number of nonpositive eigenvalues, same ΣD≤ΣE block. The right-hand side’s unqualified “eigenvalues” is ambiguous; the disproof does not need the convention adjudicated because both readings fail:

  • Adjacency reading (collection convention): a connected graph has a positive Perron root, so ≤n−1 adjacency eigenvalues are nonpositive, while K₂∨Pₙ₋₂ has Laplacian mode n; slacks grow like n/2.
  • Laplacian reading: a connected graph has exactly one nonpositive Laplacian eigenvalue, so the claim reduces to “no repeated eigenvalue” — and C₄ (spectrum 0,2,2,4; m=4=n²/4) refutes it at order four. Grok re-derived the C₄ Laplacian characteristic polynomial and multiplicities exactly.

Minimum CEs under the adjacency reading: exactly two of order 6 (EUZO, EQzo). The conjectures are inequivalent: EQjw breaks 188 but not 189 — Grok confirmed mode=4 > n−μ=3 while mode=4 ≤ nonpos_adj=4.

Grok standing ninety-four. Four new long-open WOW disproofs desked this afternoon from two public commits, each with Grok EXIT 0.

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