Carmelo Rodriguez-alvarez Universidad Complutense de Madrid   Depto. Fundamentos del Analisis Eocnomico II Fac. CC.EE.EE. Campus de Somosaguas Universidad Complutense de Madrid Pozuelo de Alarcon, Madrid 28223 Spain   carmelor@ccee.ucm.es   https://sites.google.com/site/carmeloatucm/           JEL Areas: D7 : Analysis of Collective Decision-Making: General C7 : Game Theory and Bargaining Theory:General