Microeconomics market structures/Imperfect competition

You have studied two extreme forms of market structure: one with infinite producers (perfect competition) and one with a single producer (monopoly). Realistically, within the spectrum of these two models, the vast majority of firms exist in an imperfectly competitive setting where at least one firm is a price setter. You will now study two other broad categories in the world of imperfect competition: one in which many firms compete (monopolistic competition - for example, the market for restaurants in a city) and another in which few firms compete (oligopoly - for example, the cell phone industry).