Robert Gilles Queen's University Belfast   Riddel Hall Riddel Hall 185 Stranmillis Road Belfast, Antrim BT9 5EE United Kingdom   r.gilles@qub.ac.uk   http://gilles.economics-network.org/pmwiki/pmwiki.php?n=GillesResearchSite.MainPage           JEL Areas: C7 : Game Theory and Bargaining Theory:General C : Mathematical and Quantitative Methods