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Fractional hedonic games

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  • Haris Aziz, University of New South Wales
  • ,
  • Florian Brandl, Technische Universitat Munchen
  • ,
  • Felix Brandt, Technische Universitat Munchen
  • ,
  • Paul Harrenstein, University of Oxford
  • ,
  • Martin Olsen
  • Dominik Peters, University of Oxford

The work we present in this article initiated the formal study of fractional hedonic games (FHGs), coalition formation games in which the utility of a player is the average value he ascribes to the members of his coalition. Among other settings, this covers situations in which players only distinguish between friends and non-friends and desire to be in a coalition in which the fraction of friends is maximal. FHGs thus not only constitute a natural class of succinctly representable coalition formation games but also provide an interesting framework for network clustering.We propose a number of conditions under which the core of FHGs is nonempty and provide algorithms for computing a core stable outcome. By contrast, we show that the core may be empty in other cases, and that it is computationally hard in general to decide non-emptiness of the core.

Original languageEnglish
Article numbera6
JournalACM Transactions on Economics and Computation
Publication statusPublished - Jun 2019

    Research areas

  • Coalition formation, Cooperative game theory, Core, Hedonic games

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