We study the moral hazard problem without the first-order approach or other common structure. We present sufficient conditions under which the shadow value of simultaneously tightening the minimum payment and individual rationality constraints has a simple and intuitive expression. We then show...

We provide new tools for studying asymmetric first price auctions, connecting their equilibria to the ρ-concavity of the underlying type distributions, and showing how one can use surplus expressions for symmetric auctions to bound equilibrium behavior in asymmetric auctions. We apply these...

We study the moral hazard problem with general upper and lower constraints M on compensation. We characterize the optimal contract and show existence and uniqueness. When minimizing costs for given effort, a principal harmed by M will pay according to M on some range of outcomes; when M reflects...

This paper addresses the question of what it takes to obtain a well-defined extensive form game. Without relying on simplifying finiteness or discreteness assumptions, we characterize the class of game trees for which all pure strategy combinations induce unique outcomes. The generality of the...