We consider a game between several principals and a common agent, where principals know only a subset of the agent's available actions. Principals demand robustness and evaluate contracts on a worst-case basis. This robust approach allows for a crisp characterization of the equilibrium contracts...

The unique properties of the Shapley value-efficiency, equal treatment of identical input factors, and marginality{have made it an appealing solution concept in various classes of problems. It is however recognized that the pay schemes utilized in many real-life situations generally depart from...