What is the largest number of projections onto k coordinates guaranteed in every set of m binary vectors of length n?
This fundamental question is intimately connected to important topics and results in combinatorics and computer science (Turan numbers, the Sauer-Perles-Shelah Lemma, the Kahn-Kalai-Linial Theorem, and more), and is wide open for most settings of the parameters. We essentially settle the question for all linear k and sub-exponential m.
Based on joint work with Noga Alon and Noam Solomon