The sandglass conjecture beyond cancellative pairs

Abstract

The sandglass conjecture, posed by Simonyi, states that if a pair $(A,B)$ of families of subsets of $[n]$ is recovering then $|A||B|\le 2^n$. We improve the best known upper bound to $|A||B|\le 2.2543^n$. To do this we overcome a significant barrier by exponentially separating the upper bounds on recovering pairs from cancellative pairs, a related notion.

12 pages