Question: What is the definition of a perfectly competitive industry? Which of the assumptions leads to the conclusion that typical firms in the industry earn zero economic profits in the long run? What assumptions lead to the conclusion that in the long run, the equilibrium rate of output will be at minimum average total cost? Explain your answers. How does the definition of perfect competition differ from the definition of a monopoly and how does this difference affect the long run equilibrium in a monopoly versus in a perfectly competitive industry?