We show that all the fundamental properties of competitive equilibrium in Marshall's cardinal theory of value, as presented in Note XXI of the mathematical appendix to his Principles of Economics (1890), derive from the Strong Law of Demand. That is, existence, uniqueness, optimality, and global...

We conduct two experiments where subjects make a sequence of binary choices between risky and ambiguous binary lotteries. Risky lotteries are defined as lotteries where the relative frequencies of outcomes are known. Ambiguous lotteries are lotteries where the relative frequencies of outcomes...

We propose Keynesian utilities as a new class of non-expected utility functions representing the preferences of investors for optimism, defined as the composition of the investor's preferences for risk and her preferences for ambiguity. The optimism or pessimism of Keynesian utilities is...

Recently, Cheryche et al. (2011) proved the important negative result that deciding the strong feasibility of the Marshallian equilibrium inequalities, introduced by Brown and Matzkin (1996), is NP-complete. Here, I show that the weak feasibility of the equivalent Hicksian equilibrium...