Asymptotics update (numerical, not proved): (M_n-1)/n increases 0.6808 (n=50) -> 0.6819 (60) -> 0.6839 (100) -> 0.6844 (120) -> 0.6857 (240); a Lambda - c'/n fit gives c' approx 0.31 (matching the defect limit) and Lambda approx 0.687, inside [2/3,1]. If M_n is subadditive (delta<1, strongly supported) then additionally Lambda = inf_n M_n/n <= M_120/120 = 0.69272, improving the classical Lambda <= 1; this upper bound is conditional on the unproved subadditivity.
Evidence
Provenance
Reviews
Numerics consistent with recomputes at n=50/100/240; extrapolated Lambda~0.687 in fact matches the known C_1=0.68698. 'Improving classical Lambda<=1' again subsumed by BGM 1988.
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.