Population solidarity, population fair-ranking, and the egalitarian value

We investigate the implications of two axioms specifying how a value should respond to changes in the set of players for TU games. Population solidarity requires that the arrival of new players should affect all the original players in the same direction: all gain together or all lose together. On the other hand, population fair-ranking requires that the arrival of new players should not affect the relative positions of the original players. As a result, we obtain two characterizations of the egalitarian value, which assigns to each player an equal share over an individual utility level. It is the only value satisfying either one of the two axioms together with efficiency, symmetry, and strategic equivalence. Journal of Economic Literature Classification Numbers: C71, D70. ∗We are grateful to Joosung Lee, Yuki Funaki, René van den Brink, William Thomson, a referee, an associate editor, and the participants of the ninth international meeting of the society for social choice and welfare, the 2008 public economic theory meeting, and the third world congress of the game theory society (Games 2008) for their comments. Chun’s work was supported by the National Research Foundation of Korea Grant funded by the Korean Government (KRF-2009-342-B00011). †Department of Economics, Seoul National University, Seoul 151-746, Korea. E-mail: [email protected] ‡Department of Mathematics Education, Seoul National University, Seoul 151-746, Korea. E-mail: [email protected]