Fair Congested Assignment
Year: 2025
Type: article
Abstract: We must assign n agents to m posts subject to negative congestion: what assignment is fair and efficient?If congestion is anonymous (each agent adds one unit) it is always possible to assign each agent to one of their top n out of the n×m feasible allocations. This ordinal interpretation of Ex Ante fairness still holds if congestion is weighted (agent-specific).An assignment is Competitive if I don't want to move to an empty post, or to an occupied one at its current congestion level. If it exists the competitive assignment is essentially unique, efficient and Ex Ante fair.Among agents endowed with cardinal vNM utilities we can randomise the selection of our assignment. Under anonymous congestion every problem has a unique competitive congestion profile, implemented by a mixture of deterministic assignments rounding up or down the competitive congestion, and approximately Ex Ante fair, efficient and welfare equivalent. Some of these properties are lost under weighted congestion.
Authors: Anna Bogomolnaia, Hervé Moulin
Language: English
Subfield: Economics and Econometrics
Domain: Social Sciences
Open Access status: green
OpenAlex ID: W4410154284