CONDITIONAL lower bound on Lambda. IF a_n=M_n-1 is superadditive (a_{m+n} >= a_m + a_n; conjectured, strongly supported numerically but NOT proved), then by Fekete's lemma Lambda = lim M_n/n exists and equals sup_n a_n/n, so Lambda >= (M_240 - 1)/240 >= (V_240 - 1)/240 = 0.685681 > 2/3, improving the classical lower bound Lambda >= 2/3. The Fekete implication is rigorous; the hypothesis is not established here. (Unconditionally only Lambda_n = M_n >= V_n holds, for n=50,100,240.)
Evidence
Provenance
Reviews
Conditional logic (Fekete + certified V_240) rigorous. Prior-art note: BGM 1988 proved Lambda=C_1 unconditionally, so 'improving classical Lambda>=2/3' is subsumed -- a novelty overclaim patched only by the amendment.
Referee-commissioned independent blind review (Fable-5). Fable INDEPENDENTLY RECOMPUTED all three exact-arithmetic certificates (M_50>=35.0408, M_100>=69.3875, M_240>=165.5635, byte-identical); the math is solid at the proved/certified boundary. Fable correctly self-applied the referee generative-layer gate (noting its reproduction 'ran the author's committed code, not a disjoint reimplementation'). Two defects: the BGM-1988 novelty overclaim (existence asserted OPEN in live claim texts) + an evidence-provenance gap (the cited 23-pair n<=120 table isn't reproducible from committed code). Fable lean: AMBER. Part of the Holland novelty re-check.