2 Commits

Author	SHA1	Message	Date
Marcin Pawlowski	097543a5f9	Re-measure the W pairing paired, and correct my own severity numbers ... The W = 12 pairing is now measured the way a ~0.001 claim has to be: every integer W from 8 to 15, 32 replicates, and paired_streams so the whole grid runs on common random numbers (_base_key excludes both uncle_window_anchor and window_absorption, so a replicate draws one stake vector, one graph and one lottery for every cell). The earlier unpaired sweep reported +0.0008 against a standard error of 0.0009 — it could not resolve its own headline. Paired against today's recipe (uncle-anchored, W = 10): parent W=10 -0.0056 +- 0.0005 t = -10.4 parent W=11 -0.0024 +- 0.0005 t = -4.5 parent W=12 +0.00004 +- 0.00050 t = 0.1 <- parity parent W=14 +0.0016 +- 0.0004 t = 3.5 W = 12 is the smallest window reaching parity, and the parity is exact rather than marginal: W = 11, one interval short, is still resolvably worse. p_ref agrees at the same window (0.938 vs 0.939) instead of lagging to W = 15 as the unpaired edition had it. Also states what the sweep makes visible: widening today's uncle-anchored rule buys +0.0018 on its own, so W = 12 makes the swap cost-neutral against the CURRENT recipe rather than optimal in absolute terms. CORRECTIONS to the previous commit, which measured contamination on the wrong RNG stream. The engine draws stake from seedseq_for(config).spawn(...)[0]; I used rng_for(config), the root. Both are valid stake draws, neither is the same vector. Redone properly: - The capstone draw was NOT contaminated: 0 of 8 replicates over 1.25x its label, worst 0.369 against 0.30, no majority. My "2 of 8, one a 61% majority" was wrong and is withdrawn from §8.4 and §9. - The finding that survives is sharper: on that same mild overshoot the spec's rule moved 0.001 and the parent-anchored variant moved 0.016. A rule leaning harder on the reference window is far more sensitive to an oversized suppressing coalition. - Genuinely contaminated: §6.12's 12-replicate W sweep (2 majorities, worst 0.720) and §6.8's selfish margin at a=0.3 and a=0.4 (2 and 1 majorities). §6.5's variants and §6.8's a=0.2 arm are clean; §8.3 item 20 narrowed to the one sweep that still needs re-running. - The general severity is worse than first stated, not better: at the report's geometry a nominal 0.3 realised a majority in 12% of replicates. Two more defects found on the way: - stake_for(config) added, because scripts used rng_for and the engine uses the spawned child — so every script that rebuilt a tree was analysing a different network than the trajectory it was compared against. All scripts and tests now use it. - A coalition member could receive a private block BEFORE its parent: the arrival was clamped against the PRODUCER's view of the parent and applied to the whole coalition, so a member still awaiting a public parent got the child first. Now clamped per member. Caught by the existing arrival-order test once the stake derivation was corrected. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>	2026-08-10 12:37:21 +02:00
Marcin Pawlowski	f1433cbbb3	Anchor the uncle reference window to the parent, not the uncle ... The spec bounds an uncle's own slot (0 < sl_A - sl_U <= w_u) but leaves its PARENT unconstrained beyond lying on the referencing chain. So a block minted NOW, built on a chain block from arbitrarily far back, is a legal first-fork uncle: recent by its own slot, ancient by its parent's. Verifying it means deriving the epoch state and ledger root as of that ancient parent, per reference, and those are precisely the inputs the counting rules require -- so the work cannot be amortised. It costs the adversary nothing beyond lottery wins it already has; it just builds them somewhere useless. Measured with a deep_parent coalition. At the deployed operating point a 30% adversary moves the MEDIAN counted reference's reach from 54 slots back to 20,144, and the worst case to 76,778 -- the epoch boundary, ~21 hours of history, ~256x the nominal window. It is not a tail effect. The fix is a SUBSTITUTION, not an additional rule. A block strictly postdates its parent and a referenced uncle strictly precedes its referencer, so sl_A - sl_U < sl_A - sl_parent(U) <= w_u: bounding the parent bounds the uncle for free, and a both-windows variant would be identical to the parent one. Both invariants are pinned in a new test_slot_ordering.py rather than argued -- the user asked to confirm sl_A > sl_U explicitly, and it turns out to be load-bearing for the whole implication, so it is tested at three geometries plus a hand-built counting case. Under the parent anchor the same coalition reaches 292/300/300 slots at delta_max 4/8/16 -- capped by construction. Honest recovery is unaffected: 0.9993 -> 0.9999, 0.9969 -> 0.9986, 0.9791 -> 0.9858, no loss anywhere within one to two SEM, because a latency orphan's parent is recent by construction. One finding that sharpens the case: at delta_max = 16 the HONEST uncle-anchored arm already reaches 315 slots, past its own w_u = 300. Under the current rule w_u is not a bound on validation reach even with no adversary present. It only becomes a state-retention bound once anchored to the parent. Recorded as sec 6.12 with fig38, a new row in the sec 8.5 spec deltas, both new knobs in sec 7, and the study in sec 9. uncle_window_anchor and the deep_parent strategy are appended to the RNG key only when non-default, so no committed run is reseeded. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>	2026-08-07 12:22:50 +02:00