We study the random assignment of indivisible objects among a set of agents with strict preferences. We show that there exists no mechanism which is unanimous, strategy-proof and envy-free. Weakening the first requirement to q-unanimity – i.e., when every agent ranks a different object at the...

We study the random assignment of indivisible objects among a set of agents with strict preferences. We show that there exists no mechanism which is unanimous, strategy-proof and envy-free. Weakening the first requirement to q-unanimity - i.e., when every agent ranks a different object at the...

We study the random assignment of indivisible objects among a set of agents with strict preferences. Random Serial Dictatorship is known to be only ex-post efficient and there exist mechanisms which Pareto-dominate it ex ante. However, we show that there is no mechanism that is likewise (i)...

We study the problem of assigning a set of objects to a set of agents, when each agent is supposed to receive only one object and has strict preferences over the objects. In the absence of monetary transfers, we focus on the probabilistic rules, which takes the ordinal preferences as input (the...

This paper provides two axiomatizations of the probabilistic serial mechanism. First, the mechanism is characterized by ordinal efficiency, envy-freeness, and truncation robustness. Truncation robustness restricts changes in assignments when agents truncate their preference lists. In this...