Date and Time

Friday, June 19th, 2026
17:00 p.m.-18:30 p.m.

Presenter

Dr. Flip Klijn (Institute for Economic Analysis)

Title

Core stability and strategy-proofness in hedonic coalition formation problems with friend-oriented preferences

Abstract

We study hedonic coalition formation problems with friend-oriented preferences; that is, each agent has preferences over his coalitions based on a partition of the set of agents, except himself, into “friends” and “enemies” such that (E) adding an enemy makes him strictly worse off and (F) adding a friend together with a set of enemies makes him strictly better off. Friend-oriented preferences induce a so-called friendship graph where vertices are agents and directed edges point to friends. We show that the partition associated with the strongly connected components (SCC) of the friendship graph is in the strict core. We then prove that the SCC mechanism, which assigns the SCC partition to each hedonic coalition formation problem with friend-oriented preferences, satisfies a strong group incentive compatibility property: group strategy-proofness. Our main result is that on any “rich” subdomain of friend-oriented preferences, the SCC mechanism is the only mechanism that satisfies core stability and strategy-proofness.

About

We will have a research seminar with Professor Flip Klijn from IAE-CSIC on Friday, June 19. Professpr Kliin is a microeconomic theorist whose research interests include designing and analyzing fair/stable, efficient, and strategy-proof mechanisms to assign indivisible objects to economic agents (e.g., school/university seats to children/students and related labor markets); facilitate exchanges in markets where goods or services are traded without the use of money (e.g., kidney exchange, time banks, and Erasmus exchange). He has published his work in leading a peer-reviewed journals, including AmericanEconomic Review, Journal of Economic Theory, and Games and Economic Behavior.

Venue

Mid Conference Room (Graduate School of Economics), Rokko-dai 1st Campus, Building Ⅲ 1F

Language

English

Co-organized by

Intended Participants

Professors, Graduate students including KIMAP students and Alumni of Kobe University.

How to register for this seminar

No advance registration required (please come directly to the venue)