Notes on Perfect Competition

Firms in Perfectly Competitive Markets

Market Structures

• Types: Perfect competition, Monopolistic competition, Oligopoly, Monopoly.

Characteristics of Market Structures

• Number of firms in the industry.
• Similarity of the goods/services produced.
• Ease of entry for new firms.

Comparative Overview of Market Structures

Conditions for Perfect Competition

1. Many buyers and sellers, small relative to market.
2. All firms sell identical products.
3. No barriers to entry or exit.

Price and Demand in Perfectly Competitive Markets

• Price Taker: Firm that cannot affect market price. Demand curve is horizontal (perfectly elastic).
• Market equilibrium price is determined by the intersection of supply and demand.

Profit Maximization

• Definition: Profit = Total Revenue (TR) - Total Cost (TC).
• Rule: Profit maximization occurs where MR = MC.

Marginal Revenue

• Definition: Change in total revenue from selling one more unit. In perfect competition, AR = MR = Price.

Firm's Supply Curve

• The marginal cost curve represents the firm's supply curve for prices equal to or above average variable cost.

Short Run Decisions

• Firm can continue producing or shut down temporarily if suffering losses.
• Shutdown Point: Firm will stop production if P < AVC.

Economic Profit and Losses

• Economic Profit: Revenues - Total Costs (including implicit costs). Only occurs in short run in perfectly competitive markets.
• Economic Loss: Firm experiences revenue less than total costs, leading to potential exit from the market.

Long-Run Equilibrium

• Condition where typical firm breaks even; long-run price is at minimum average cost.
• If firms enter or exit, the market supply adjusts to maintain equilibrium.

Efficiency in Perfect Competition

• Productive Efficiency: Goods produced using the least resources.
• Allocative Efficiency: Production reflects consumer preferences; marginal benefit equals marginal cost.