A barrier to entry exists when firms in an industry charge the lowest price possible for their
products.
If economies of scale are significant, the typical firm will not reach the minimum point on its
long–run average cost curve until it has produced a large fraction of industry sales.
When a monopolistically competitive firm cuts its price to increase its sales it experiences a loss in
revenue due to the income effect and a gain in revenue due to the substitution effect.
An equilibrium in which each player chooses its best strategy given the strategies chosen by the
other players, is called a Nash equilibrium.
A monopolistic competitor does not earn profits in the long run unless it can successfully
differentiate its product in the minds of its consumers.
In monopolistic competition if a firm produces a highly desirable product relative to its
competitors, the firm will be able to raise its price without losing any customers.
A monopolistically competitive industry that earns economic profit in the short run will be able to
expand its market share even if the market size remains constant.
In a Nash equilibrium, all players select non–dominant strategies.
For a monopolistically competitive firm price equals average revenue.
In long–run equilibrium, a perfectly competitive firm and a monopolistically competitive firm
produce the output at which MR=MC and charge a price equal to the average total cost of
production.