Profit rates differ across industries. Explanations have often relied on static models of imperfect competition. This paper develops a dynamic model of perfect competition to demonstrate that long-run average profit rates differ even across competitive industries when the effects of sunk costs...

Optimal penal codes are constructed for a class of infinity-repeated games with discounting. These games can be interpreted as Bertrand oligopoly games with capacity constraints. No particular rationing rule is adopted; weak restrictions are imposed on the firms' sales functions instead. Models...

An important question is how well competitive models approximate models of large finite economies. For a class of differentiated products models, static Nash equilibria, if they exist, always converge to competition as the number of firms increases. Dynamic Nash equilibria need not so converge....

In the framework of symmetric Cournot oligopoly, this paper provides two minimal sets of assumptions on the demand and cost functions that imply respectively that, as the number of firms increases, the minimal and maximal equilibria lead to (i) decreasing industry price and increasing or...