A coding problem for pairs of subsets

Bela Bollobas, Zoltan Furedi, Ida Kantor +2

Let $X$ be an $n$--element finite set, $0<k\le n/2$ an integer. Suppose that $\{A_1,A_2\}$ and $\{B_1,B_2\}$ are pairs of disjoint $k$-element subsets of $X$ (that is, $|A_1|=|A…