House Allocation with Existing Tenants : A Characterization

We analyze mechanisms that are used to allocate dormitory rooms to students at college campuses. Students consist of newcoming freshmen, who do not currently occupy any rooms, and more senior students each of whom occupies a room from the previous year. In addition to the rooms already occupied by the existing tenants, there are vacated rooms by the graduating class. Students have strict preferences over dormitory rooms. Each student shall be assigned a dormitory room in an environment where monetary transfers are not allowed. An existing tenant can move to another room as a result of the assignment. We show that you request my house-I get your turn mechanisms introduced by Abdulkadiroglu and Sonmez (Journal of Economic Theory, 1999) are the only mechanisms that are Paretoefficient, individually rational, strategy-proof, weakly neutral, and consistent