The document discusses monopolistic competition in the toothpaste market using Crest toothpaste as an example. It notes that while Procter & Gamble has monopoly power over Crest, their power is limited because consumers can easily substitute other brands if the price rises too much. The demand for Crest is downward sloping but fairly elastic. As a result, Procter & Gamble will charge a price only slightly higher than their marginal cost.