Séminaire Microéconomie : Tous les mercredis
Heure : 12h15 – 13h30
Date :21/05/2025
Salle : 3001

Alex TEYTELBOYM (Oxford) – “Fair and Efficient Combinatorial Assignment (with Thành Nguyen and Shai Vardi)”

CV : Fair and efficient assignment of indivisible goods without the use of money often involves randomization. However, existing mechanisms in combinatorial assignment settings only ensure desirable properties either ex ante or ex post, but not both. We introduce a class of mechanisms in which agents face a single competitive price vector that exactly clears the ex-ante economy while approximately clearing every ex-post economy. Our Competitive Equilibrium from Random Incomes (CERI) assigns each agent a random budget of tokens, determines a profile of optimal lotteries, and sets prices that exactly clear the ex-ante economy. A CERI exists for any continuous distribution of token budgets. We establish that an allocation is ordinally efficient if and only if it is a CERI allocation and any CERI allocation can be implemented as a lottery over ex-post efficient near-feasible allocations. When token budget distributions are identical, the CERI allocation is ordinally envy-free, and when they have sufficiently small support, then every realization of the CERI allocation is ex-post envy- free up to one good. Using the single market-clearing price, we design an asymptotically efficient and envy-free implementation of CERI that ensures that all agents have a dominant strategy to report their preferences truthfully with an arbitrarily high probability in large markets. CERI therefore fully captures difficult tradeoffs between efficiency, equity and incentive compatibility in combinatorial assignment and can be practically used for a variety of applications include course allocation, allocation of food donations to food banks, and refugee resettlement.

Organisateurs :

Julien COMBE (Pôle d’Economie du CREST)
​​​​​​​​​​​​Yves Le YAOUANQ (Pôle d’Economie du CREST)
​​​​​​​​​Matias NUNEZ (Pôle d’Economie du CREST)

Commanditaires :
CREST