Problem: Using diagrams for both the industry and a representative firm, illustrate competitive long run equilibrium. Assuming constant costs, employ these diagrams to show how (a) an increase and (b) a decrease in market demand will upset the long-run equilibrium. Trace graphically and describe verbally the adjustment processes by which long-run equilibrium is restored. Now rework your analysis for increasing and decreasing-cost industries and compare the three long run supply curves.