Game Theory Ani Guerdjikova University of Cergy-Pontoise THEMA ani.guerdjikova@u-cergy.fr Fall 2011 Lectures: Tuesday 9:30 – 12:45 Description of the course: The course introduces the main concepts and tools of game theory with the aim to enable you to read original game-theoretic literature and to prepare you to do research in the field. You will learn how to represent an economic situation as a game (part 1) and how to analyze it using different equilibrium concepts proposed in the literature, the prominent one being the Nash equilibrium (parts 2 and 3). In part 4, we will concentrate on strategic interaction under incomplete information and modify the Nash equilibrium concept to include the uncertainty of the players about some of the parameters of the game. Often, an equilibrium concept fails to provide a unique solution to the game. In part 5, we will deal with the problem of indeterminacy in games in extensive form and introduce refinements of the Nash equilibrium. Requirements: Homework assignments will be distributed during the term. A final exam will be held in the last week of classes. Recommended books: 1. Eichberger, J. (1993). Game Theory for Economists, Academic Press, San Diego. 2. Fudenberg, D., Tirole, J. (1991). Game Theory, MIT Press, Cambridge, Massachussets. 3. Osborne, M., Rubinstein, A. (1994). A Course in Game Theory, MIT Press, Cambridge, Massachussets. 4. Mas-Collel, A., Whinston, M. D., Green, J. R. (1995). Microeconomic Theory, Oxford University Press, New York, Oxford. (Chapters 13, 14) Note: I do not expect you to buy or to study all three game-theory books – you are at liberty to choose the one that suits you most or even to use a different graduate level game theory book. (E.g., Mas-Collel also contains most of the game-theoretic material we are going to cover. However, check your understanding before settling for this option!). However, you are expected to know and understand the material at the level at which it is presented in these books. I also expect you to read and try to understand the papers which appear on the syllabus. Many of them are the original versions of well known results you will find in the text books. You should pay special attention to the discussion of the assumptions and of the results. Many of these „classical“ papers in game theory are collected in the book „Classics in Game Theory“. Course materials: The lecture slides are available on line at: http://www.arts.cornell.edu/econ/guerdjikova/ (click on Teaching and choose ECON 611). 1. Formal Representation of Games a. Games in extensive form b. Concepts of strategies c. Games in strategic form Rubinstein, A. (1989). “The Electronic Mail Game: Strategic Behavior Under Almost Common Knowledge”, American Economic Review 79: 385-379. Issue 20 of Games and Economic Behavior (1997) is devoted to imperfect recall. 2. Dominance Arguments a. Dominant strategy equilibrium Vickrey, W. (1961). “Counterspeculation, Auctions and Competitive Sealed Tenders”, Journal of Finance 16: 8-37. Clarke, E. H. (1971). “Multipart Pricing of Public Goods”, Public Choice 2: 19-33. b. Iterative elimination of dominated strategies c. Rationalizable strategies Pearce, D. (1984). "Rationalizable Strategic Behavior and the Problem of Perfection", Econometrica 52:1029-1050. Bernheim, B. D. (1984). "Rationalizable Strategic Behavior", Econometrica 52: 1007-1028. 3. Nash Equilibrium a. Definition, existence and uniqueness of a Nash equilibrium Nash Jr., J. F. (1950). "Equilibrium Points in N-Person Games", Proceedings Nat. Academy Sciences USA 36, pp. 48-49. b. Trembling-hand perfect equilibrium Selten, R. (1975). "Reexamination of the perfectness concept for equilibrium points in extensive games", International Journal of Game Theory 4: 25-55. c. Proper equilibrium 4. Games with Incomplete Information a. Bayesian decision theory b. Bayes-Nash equilibrium Harsanyi, J. (1967). "Games of incomplete information played by Bayesian players", Parts I, II, III, Management Science, 14: 159-182, 320-334, 486-502. Wolfstetter, E. (2002). Topics in Microeconomics, Chapter 8: Auctions, Cambridge University Press. 5. Refinements of the Nash Equilibrium a. Subgame perfect equilibrium Selten, R. (1975). "Reexamination of the perfectness concept for equilibrium points in extensive games", International Journal of Game Theory 4: 25-55. b. Perfect Bayesian equilibrium c. Sequential equilibrium Kreps, D., Wilson, R., (1982). "Sequential Equilibrium", Econometrica 50: 86394.