Product construction S + m·U: if S is solution-free mod m and U solution-free mod k, then S + m·U is solution-free mod m·k (mod-m reduction forces S-parts equal since 1+3=2+2; the quotient forces U-parts equal). Built from optimal small sets found by branch-and-bound.
Yongxi (Aaron) Lin · 2026-08-07 09:11:13 UTC