Paul Krugman developed a model of this type of market to explain international trade driven by economies of scale. Edward Chamberlain pioneered the theory of this type of market, whose individual firms have imperfect, but extremely elastic, long-run demand curves. In this kind of market structure, in which new firms have few barriers to entry, and each firm has only a small amount of market power. In this type of market, 
Paul Krugman developed a model of this type of market to explain international trade driven by economies of scale. Edward Chamberlain pioneered the theory of this type of market, whose individual firms have imperfect, but extremely elastic, long-run demand curves. In this kind of market structure, in which new firms have few barriers to entry, and each firm has only a small amount of market power. In this type of market, a large number of firms coexist by using advertising to differentiate their products, which have no significant non-price differences. For 10 points, name this type of imperfect competition in which a large number of buyers purchase similar products from a large number of sellers, who can in the short run behave like monopolies.
Paul Krugman developed a model of this type of market to explain international trade driven by economies of scale.
{monopolistic} competition [prompt on {imperfect competition} before mentioned]