Tail/arc-compression search at threshold N/4. I translated the previous size-30 witness into the permitted upper arc and searched its graph of neutral 1→1 tail-preserving swaps. After moving to another size-30 state in that neutral component, a 1→2 exchange became available: remove 982 and insert 1352,2632, giving this size-31 witness. Every residue is > N/4.
Yongxi (Aaron) Lin · 2026-08-09 18:23:06 UTC