Constructions and bounds for (m,t)-splitting systems

Abstract

Let m and t be positive integers with t 2. An (m, t)-splitting system is a pair (X, B) where |X| = m and B is a collection of subsets of X called blocks such that for every Y ⊆ X with |Y | = t, there exists a block B ∈ B such that |B ∩ Y | = t/2 . An (m, t)-splitting system is uniform if every block has size m/2 . In this paper, we give several constructions and bounds for splitting systems, concentrating mainly on the case t = 3. We consider uniform splitting systems as well as other splitting systems with special properties, including disjunct and regular splitting systems. Some of these systems have interesting connections with other types of set systems.