13. – 18. Juni 2021, Dagstuhl-Seminar 21241

RESCHEDULED Coalition Formation Games

Due to the Covid-19 pandemic, this seminar was rescheduled to 15. – 20. August 2021Seminar 21331.


Edith Elkind (University of Oxford, GB)
Judy Goldsmith (University of Kentucky – Lexington, US)
Anja Rey (Universität Köln, DE)
Jörg Rothe (Heinrich-Heine-Universität Düsseldorf, DE)

Auskunft zu diesem Dagstuhl-Seminar erteilt

Dagstuhl Service Team


There are many situations in which individuals will choose to act as a group, or coalition. Examples include social clubs, political parties, partnership formation, and legislative voting. Coalition formation games are a class of cooperative games where the aim is to partition a set of agents into coalitions, according to some criteria, such as coalitional stability or maximization of social welfare. We are particularly interested in a subclass of coalition formation games, hedonic games, which were first proposed by Drèze and Greenberg (1980) and later formalized by Banerjee et al. (2001) and Bogomolnaia and Jackson (2002). Hedonic sames are distinguished from general coalition formation games by the requirement that each agent's utility is wholly derived from the members of their own coalition.

This Dagstuhl Seminar brings multiple approaches and viewpoints to the study of coalition formation games, and in particular hedonic games, mainly from the perspective of computer science and economics. Particular topics to be discussed in talks and working groups include (but are not limited to):

  • succinctly representable preferences over coalitions;
  • the existence and verification of stable coalition structures (for various stability concepts);
  • the computational complexity of finding or verifying stable or optimal partitions, or even determining whether such partitions exist;
  • designing (if possible, efficient) algorithms for finding stable or optimal (or nearly so) coalition structures, or for verifying that a coalition structure is (nearly) stable or optimal;
  • stability notions restricted to social networks or other networks;
  • matching markets and matching under preferences, and their relation to hedonic games;
  • dynamics of coalition formation; and
  • group activity selection.

The overarching theme of this Dagstuhl Seminar is to bring together different communities working in coalition formation and hedonic games from various perspectives in computer science and economics and to bridge and bundle their research activities. Participants can form working groups that each will focus on exploring some of the challenging open questions of the field – this is coalition formation in action. Much of the great atmosphere of the seminars at Schloss Dagstuhl comes from informal meetings besides the official schedule, with participants doing leisure activities together and enjoying other joint undertakings – this is group activity selection in practice.

Motivation text license
  Creative Commons BY 3.0 DE
  Edith Elkind, Judy Goldsmith, Anja Rey, and Jörg Rothe

Related Dagstuhl-Seminar


  • Computational Complexity
  • Computer Science And Game Theory
  • Social And Information Networks


  • Coalition formation games
  • Hedonic games
  • Preferences
  • Cooperative game theory


In der Reihe Dagstuhl Reports werden alle Dagstuhl-Seminare und Dagstuhl-Perspektiven-Workshops dokumentiert. Die Organisatoren stellen zusammen mit dem Collector des Seminars einen Bericht zusammen, der die Beiträge der Autoren zusammenfasst und um eine Zusammenfassung ergänzt.


Download Übersichtsflyer (PDF).

Dagstuhl's Impact

Bitte informieren Sie uns, wenn eine Veröffentlichung ausgehend von Ihrem Seminar entsteht. Derartige Veröffentlichungen werden von uns in der Rubrik Dagstuhl's Impact separat aufgelistet  und im Erdgeschoss der Bibliothek präsentiert.


Es besteht weiterhin die Möglichkeit, eine umfassende Kollektion begutachteter Arbeiten in der Reihe Dagstuhl Follow-Ups zu publizieren.