Carmelo Rodriguez-alvarez ICAE - Universidad Complutense de Madri   ICAE - Facultad CC. Economicas Campus de Somosaguas 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