Ex-Ante Pareto Efficiency For the Random Assignment Problem
We introduce ex-ante Pareto efficiency, which is a slightly weaker notion of efficiency than ex-post Pareto efficiency. We strengthen the impossibility between ex-post Pareto efficiency, strategyproofness, and envy-freeness in the random assignment problem and show that it prevails if ex-post Pareto efficiency is weakened to ex-ante Pareto efficiency