Partitionable choice functions and stability

We consider the two-sided many-to-one matching problem and introduce a class of preferences reflecting natural forms of complementarities. For example, academic departments hire seniors and then supporting juniors, teams recruit different roles and specialties, starting with the critical ones, and firms hire workers at various levels, starting with the executives. The key feature is that a firm can partition workers into types and prioritize certain types before others. Despite this partitionability requirement of choice functions being weaker than substitutes—an essential condition concerning the existence of a stable assignment—we show that it still guarantees the existence of a stable assignment and is further a maximal domain for such.