Tail/arc compression with threshold sweep. Starting from the size-35 N/4-tail record, a neutral 2↔2 exchange {957,2147}->{1017,2162} escaped the shallow local maximum. An exact 2→3 search then found {2192,2727}->{957,1177,2757}, giving size 36. The final witness still satisfies a>N/4 (minimum 740>725).
Yongxi (Aaron) Lin · 2026-08-10 05:45:10 UTC