The majority of results in the literature on general equilibrium are not for an economy (i.e. given an endowment and preferences), but rather, for a set of economies (i.e. a set of endowments given preferences). Therefore, we argue that the most appropriate robustness result requires perturbing...

We study transactions that require investments before trading in a competitive market, when forward contracts fixing the transaction price are absent. We show that, despite the market being perfectly competitive and subject to arbitrarily little uncertainty, the inability to jointly determine...

Job security provisions are commonly invoked to explain the high and persistent European unemployment rates. This belief has led several countries to reform their labor markets and liberalize the use of fixed-term contracts. Despite how common such contracts have become after deregulation, there...

This collection of essays honors David Cass on the 30th anniversary of his joining the faculty of the Department of Economics at the University of Pennsylvania. Prof. Cass's work has spawned a number of important lines of research in Economics, including the study of dynamic general equilibrium,...