Problem Statement
Is there a covering system such that no two of the moduli divide each other?
Categories:
Number Theory Covering Systems
Progress
Asked by Schinzel, motivated by a question of Erdős and Selfridge (see [7]). The answer is no, as proved by Balister, Bollobás, Morris, Sahasrabudhe, and Tiba [BBMST22].Source: erdosproblems.com/586 | Last verified: January 15, 2026