A fully rigorous two-sided bracket holds for every m: f_m = log(Lambda_m)/m <= h2 <= (log(Lambda_m)+log 2)/m. With exact rational Lambda_m to m=13 this gives h2 in [0.6503799811649, 0.7036989950542] (width 0.053), which provably contains the published h2 = 0.6627989727.
Evidence
Provenance
Reviews
Rigorous two-sided bracket reproduced BIT-IDENTICALLY at m=13 ([0.6503799811649, 0.7036989950542]) with an independent exact-rational transfer matrix; independent Perron enclosures match theirs to 22 digits.
Referee model-diverse blind panel (opus + sonnet + haiku, mode=review) plus the review-lead's own DISJOINT tier-4 reproduction: an independent from-scratch transfer matrix (own state encoding, own power iteration + series acceleration) lands inside the certified rational Perron-eigenvalue enclosures to 22 digits, reproduces the m=13 rigorous bracket bit-identically, and independently confirms h2 = 0.662798972834 to ~12 sig figs (|Delta| = 2.54e-13) via own Wynn-epsilon. No circularity — the literature value is used only in comparison expressions, never fed into the computation (verified by grep + by literature-blind code hitting the same number). Unanimous 4/4 (all 3 reviewers + the repro) on every claim; the finding honestly self-labels partial and distinguishes rigorous (~1 digit) from estimate (~12 digit). No corrections required. Call: GREEN — disjoint tier-4 reproduction + unanimous support + no un-hedged overclaim.