Daniel Cardona Universitat de les Illes Balears and CREB   Departament Economia Aplicada Campus UIB Ctra. valldemossa km. 7.5 Palma, Illes Balears 07122 Spain   d.cardona@uib.cat   http://www.uib.es/depart/deaweb/webpersonal/danielcardona/           JEL Areas: C7 : Game Theory and Bargaining Theory:General D6 : Welfare Economics: General