In the standard formulation of game theory, agents use mixed strategies in the form of objective and probabilistically precise devices to conceal their actions. We introduce the larger set of probabilistically imprecise devices and study the consequences for the basic results on normal form...

The paper explores the role of price or quantity leadership in facilitating collusion. It extends the standard analysis of tacit collusion by allowing firms to make their strategic choices either simultaneously or sequentially. It is shown that price leadership indeed facilitates collusion by...

In infinite horizon economies only local equivalence of beliefs is needed to ensure the existence of an Arrow–Debreu equilibrium. In fact, agents can even disagree completely in the long run in the sense that asymptotically, their beliefs are singular. Copyright Springer-Verlag Berlin...