Invited Speaker at Nonclassical Logics: from foundations to applications, Pisa, Italy (2008), by Invitation (Centro di Ricerca Matematica Ennio De Giorgi of the Scuola Normale, 2008)
Invited Speaker First International Workshop on Game Theory, Milan, Italy (2008), by Invitation (Center for Interdisciplinary Studies in Economics, Psychology and Social Sciences (CISEPS), 2008)
Invited talk, by Invitation (Barcelona, Spain, 2008)
Invited Talk at Methods for Modalities (M4M), Paris, France (2007), by Invitation (The organisers, 2007)
Keynote Speech at Multi-Agent Logics, Languages and Organisations (MALLOW) Durham, UK (2007), Keynote/Plenary by Invitation (the organisers, 2007)
Invited Talk at Logics, Rationality and Interaction (LORI), Beijing, Cina (2007), by Invitation (the Organisers, 2007)
Keynote Speech International Conference on Conceptual Structures (ICCS) Sheffield, UK (2007), Keynote/Plenary by Invitation (the Organisers, 2007)
Keynote Speech at Modeles Formels de l'Interaction (MFI), Paris, France (2007), Keynote/Plenary by Invitation (the organisers, 2007)
Invited Seminar Speaker, Leipzig, Germany, by Invitation (Intelligent Systems Department, 2007)
Invited Talk at Logics and Collective Decsision Making (LCD), Lille France (2007), by Invitation (the organisers, 2007)
Invited Seminar Speaker, Bristol, UK, by Invitation (Department of Philosophy, Bristol, 2007)
Invited Talk at Dutch Association for Logic Utrecht, the Netherlands (2007), by Invitation (Vereniging voor Logica (VVL), 2007)
Invited Speaker at Games, Action and Social Software, Leiden, the Netherlands (2006), by Invitation (Netherlands Institute for Advanced Study (NIAS), 2006)
Invited Speaker at Studia Logica Conference, Turin, Poland (2006), by Invitation (The Board of Studia Logica, 2006)
Invited speaker at the 7th De Morgan Workshop, London, UK (2005), by Invitation (the organisers, 2005)
Invited Speaker at Understanding the Dynamics of Knowledge, Siena, Italy (2005), by Invitation (The organisers, 2005)
Invited Speaker at Computational Models of Scientific Reasoning, Lisbon, Portugal (2005), by Invitation (the organisers, 2005)
Invited Speaker Advances in Modal Logic, Manchester, UK (2005), by Invitation (the organisers, 2005)
Invited speaker at Logic Colloquium, Athens, Greece (2005), by Invitation (Association for Symbolic Logic (ASL), 2005)
Invited Lecture at Brazilian Agent School, Porto Alegre, Brazil (2005), by Invitation (the organisers, 2005)
Invited Speaker at BCS SGAI Symposium, Edinburgh, UK (2004), by Invitation (the organisers, 2004)
Keynote Speech at International Joint Conference on AAMAS, New York, USA (2004), Keynote/Plenary by Invitation (AAMAS committee, 2004)
Invited Speaker at Social Software, Copenhagen, Denmark (2004), by Invitation (the organisers, 2004)
Keynote Speech at School on Information and Knowledge Systems, Amsterdam (2004), Keynote/Plenary by Invitation (SIKS Research School, 2004)
Keynote Speech at European Workshop for Agents and Multi-Agent Systems Oxford, UK (2003) , Keynote/Plenary by Invitation (EUMAS Board, 2003)
Invited Speaker at 5th De Morgan Workshop, London, UK (2003), by Invitation (the organisers, 2003)
Invited Speaker at Games, Logic, Language and Computation, Groningen, the Netherlands (2003), by Invitation (the organisers, 2003)
Invited Speaker at Logic-Based Agent Implementation, Barcelona, Spain (2003), by Invitation (AgentLink & Colognet , 2003)
Invited speaker at Agentlink/Compulog Symposium, Barcelona (2003), by Invitation (the organisers, 2003)
Invited Lecture at Amaricas School on Agents and Multi-Agent Systems Acapulco, Mexico (2003), by Invitation (the organisers, 2003)
Keynote Speech at Logics for Agents and Multi-Agent Systems, Dunedin, New Zealand (2002), Keynote/Plenary by Invitation (SIKS Research School, 2002)
Invited Speaker at Games, Logic, Language and Computation,Utrecht, the Netherlands (20020, by Invitation (Board of GLLC, 2002)
Invited speaker at Dimensions of Epistemic Logic Roskilde, Denmark (2002), by Invitation (the organisers, 2002)
Invited Speaker at Designing Behaviour, Amsterdam, the Netherlands (2002), by Invitation (Mediametic, 2002)
Invited Lecture at School for Information and Knowledge Systems (Amsterdam, 2001), by Invitation (SIKS Research School, 2001)
Keynote Speech at Conference on Information and Computation, Mexico (2000), Keynote/Plenary by Invitation (the organisers, 2000)
Invited speaker at Foundations of Game and Decision Theory, Marseille, France (1996), by Invitation (the organisers, 1996)
Invited Speaker at Partial, Epistemic and Dynamic Logic, Montreal, Canada (1995), by Invitation (the organisers, 1995)
Editorships
Logic and the Foundations of Game and Decision Theory (LOFT) (Program Committee (Co-Chair))
AAMAS (Program Committee (Co-Chair), 2010)
German Conference on Multi-Agent Systems (MATES) (Program Committee (Co-Chair), 2009)
21st International Joint Conference on Artificial Intelligence (IJCAI-09) (Programme Committee (Member), 2009)
International Conference on the Principles of Knowledge Representation and Reasoning (KR) (Programme Committee (Member), 2008 - 2010)