Ordinality in Random Allocation

Abstract: In allocating objects via lotteries, it is common to consider ordinal rules that rely solely on how agents rank degenerate lotteries. While ordinality is often imposed due to cognitive or informational constraints, we provide another justification from an axiomatic perspective: for three-agent problems, the combination of efficiency, strategy-proofness, non-bossiness, and a weak form of continuity collectively implies ordinality.