a) Please explain the difference between the collusive and competitive oligopoly models and explain the role that the number of firms and barriers to entry play in determining how real-world oligopolistic industries behave.
b) Show graphically and explain how a monopoly results in a deadweight loss. Also point out the redistribution that takes place in society because of monopoly. (*edit: You don't have to give graph if you do not know it, though it would be nice. I mainly need the explanation and to point out the redistribution that takes place)