We present some examples of Nash equilibria that are independent of the distribution of some parameter across the economic agents and describe a general theorem that characterizes this phenomenon.

When is the Pareto optimal amount of public goods independent of income distribution? Subject to some regularity conditions, the answer is when preferences of every individual i can be represented by a utility function of the form U(X_i,Y)=A(Y)X_i+B_i(Y) where X_i is i's consumption of private goods and Y is the amount of public goods.

In most times and places, women on average marry older men. We propose a partial explanation for this difference and for why it is diminishing. In a society in which the economic roles of males are more varied than the roles of females, the relative desirability of females as marriage partners may become evident at an earlier age than is the case for males. We study an equilibrium model in which the males who regard their prospects as unusually good choose to wait until their economic success is revealed before choosing a bride. In equilibrium, the most desirable young females choose successful older males. Young males who believe that time will not treat them kindly will offer to marry at a young age. Although they are aware that young males available for marriage are no bargain, the less desirable young females will be offered no better option than the lottery presented by marrying a young male. We show the existence of equilibrium for models of this type and explore the properties of equilibrium.