Collusion in Markets with Syndication
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Best Experienced Payoff Dynamics and Cooperation in the Centipede Game
Theoretical Economics 14 (2019), 1347–1385 1555-7561/20191347 Best experienced payoff dynamics and cooperation in the centipede game William H. Sandholm Department of Economics, University of Wisconsin Segismundo S. Izquierdo BioEcoUva, Department of Industrial Organization, Universidad de Valladolid Luis R. Izquierdo Department of Civil Engineering, Universidad de Burgos We study population game dynamics under which each revising agent tests each of his strategies a fixed number of times, with each play of each strategy being against a newly drawn opponent, and chooses the strategy whose total payoff was highest. In the centipede game, these best experienced payoff dynamics lead to co- operative play. When strategies are tested once, play at the almost globally stable state is concentrated on the last few nodes of the game, with the proportions of agents playing each strategy being largely independent of the length of the game. Testing strategies many times leads to cyclical play. Keywords. Evolutionary game theory, backward induction, centipede game, computational algebra. JEL classification. C72, C73. 1. Introduction The discrepancy between the conclusions of backward induction reasoning and ob- served behavior in certain canonical extensive form games is a basic puzzle of game the- ory. The centipede game (Rosenthal (1981)), the finitely repeated prisoner’s dilemma, and related examples can be viewed as models of relationships in which each partic- ipant has repeated opportunities to take costly actions that benefit his partner and in which there is a commonly known date at which the interaction will end. Experimen- tal and anecdotal evidence suggests that cooperative behavior may persist until close to William H. -
Minimax TD-Learning with Neural Nets in a Markov Game
Minimax TD-Learning with Neural Nets in a Markov Game Fredrik A. Dahl and Ole Martin Halck Norwegian Defence Research Establishment (FFI) P.O. Box 25, NO-2027 Kjeller, Norway {Fredrik-A.Dahl, Ole-Martin.Halck}@ffi.no Abstract. A minimax version of temporal difference learning (minimax TD- learning) is given, similar to minimax Q-learning. The algorithm is used to train a neural net to play Campaign, a two-player zero-sum game with imperfect information of the Markov game class. Two different evaluation criteria for evaluating game-playing agents are used, and their relation to game theory is shown. Also practical aspects of linear programming and fictitious play used for solving matrix games are discussed. 1 Introduction An important challenge to artificial intelligence (AI) in general, and machine learning in particular, is the development of agents that handle uncertainty in a rational way. This is particularly true when the uncertainty is connected with the behavior of other agents. Game theory is the branch of mathematics that deals with these problems, and indeed games have always been an important arena for testing and developing AI. However, almost all of this effort has gone into deterministic games like chess, go, othello and checkers. Although these are complex problem domains, uncertainty is not their major challenge. With the successful application of temporal difference learning, as defined by Sutton [1], to the dice game of backgammon by Tesauro [2], random games were included as a standard testing ground. But even backgammon features perfect information, which implies that both players always have the same information about the state of the game. -
Evolutionary Stable Strategy Application of Nash Equilibrium in Biology
GENERAL ARTICLE Evolutionary Stable Strategy Application of Nash Equilibrium in Biology Jayanti Ray-Mukherjee and Shomen Mukherjee Every behaviourally responsive animal (including us) make decisions. These can be simple behavioural decisions such as where to feed, what to feed, how long to feed, decisions related to finding, choosing and competing for mates, or simply maintaining ones territory. All these are conflict situations between competing individuals, hence can be best understood Jayanti Ray-Mukherjee is using a game theory approach. Using some examples of clas- a faculty member in the School of Liberal Studies sical games, we show how evolutionary game theory can help at Azim Premji University, understand behavioural decisions of animals. Game theory Bengaluru. Jayanti is an (along with its cousin, optimality theory) continues to provide experimental ecologist who a strong conceptual and theoretical framework to ecologists studies mechanisms of species coexistence among for understanding the mechanisms by which species coexist. plants. Her research interests also inlcude plant Most of you, at some point, might have seen two cats fighting. It invasion ecology and is often accompanied with the cats facing each other with puffed habitat restoration. up fur, arched back, ears back, tail twitching, with snarls, growls, Shomen Mukherjee is a and howls aimed at each other. But, if you notice closely, they faculty member in the often try to avoid physical contact, and spend most of their time School of Liberal Studies in the above-mentioned behavioural displays. Biologists refer to at Azim Premji University, this as a ‘limited war’ or conventional (ritualistic) strategy (not Bengaluru. He uses field experiments to study causing serious injury), as opposed to dangerous (escalated) animal behaviour and strategy (Figure 1) [1]. -
Game Theory]: Basics of Game Theory
Artificial Intelligence Methods for Social Good M2-1 [Game Theory]: Basics of Game Theory 08-537 (9-unit) and 08-737 (12-unit) Instructor: Fei Fang [email protected] Wean Hall 4126 1 5/8/2018 Quiz 1: Recap: Optimization Problem Given coordinates of 푛 residential areas in a city (assuming 2-D plane), denoted as 푥1, … , 푥푛, the government wants to find a location that minimizes the sum of (Euclidean) distances to all residential areas to build a hospital. The optimization problem can be written as A: min |푥푖 − 푥| 푥 푖 B: min 푥푖 − 푥 푥 푖 2 2 C: min 푥푖 − 푥 푥 푖 D: none of above 2 Fei Fang 5/8/2018 From Games to Game Theory The study of mathematical models of conflict and cooperation between intelligent decision makers Used in economics, political science etc 3/72 Fei Fang 5/8/2018 Outline Basic Concepts in Games Basic Solution Concepts Compute Nash Equilibrium Compute Strong Stackelberg Equilibrium 4 Fei Fang 5/8/2018 Learning Objectives Understand the concept of Game, Player, Action, Strategy, Payoff, Expected utility, Best response Dominant Strategy, Maxmin Strategy, Minmax Strategy Nash Equilibrium Stackelberg Equilibrium, Strong Stackelberg Equilibrium Describe Minimax Theory Formulate the following problem as an optimization problem Find NE in zero-sum games (LP) Find SSE in two-player general-sum games (multiple LP and MILP) Know how to find the method/algorithm/solver/package you can use for solving the games Compute NE/SSE by hand or by calling a solver for small games 5 Fei Fang 5/8/2018 Let’s Play! Classical Games -
The Three Types of Collusion: Fixing Prices, Rivals, and Rules Robert H
University of Baltimore Law ScholarWorks@University of Baltimore School of Law All Faculty Scholarship Faculty Scholarship 2000 The Three Types of Collusion: Fixing Prices, Rivals, and Rules Robert H. Lande University of Baltimore School of Law, [email protected] Howard P. Marvel Ohio State University, [email protected] Follow this and additional works at: http://scholarworks.law.ubalt.edu/all_fac Part of the Antitrust and Trade Regulation Commons, and the Law and Economics Commons Recommended Citation The Three Types of Collusion: Fixing Prices, Rivals, and Rules, 2000 Wis. L. Rev. 941 (2000) This Article is brought to you for free and open access by the Faculty Scholarship at ScholarWorks@University of Baltimore School of Law. It has been accepted for inclusion in All Faculty Scholarship by an authorized administrator of ScholarWorks@University of Baltimore School of Law. For more information, please contact [email protected]. ARTICLES THE THREE TYPES OF COLLUSION: FIXING PRICES, RIVALS, AND RULES ROBERTH. LANDE * & HOWARDP. MARVEL** Antitrust law has long held collusion to be paramount among the offenses that it is charged with prohibiting. The reason for this prohibition is simple----collusion typically leads to monopoly-like outcomes, including monopoly profits that are shared by the colluding parties. Most collusion cases can be classified into two established general categories.) Classic, or "Type I" collusion involves collective action to raise price directly? Firms can also collude to disadvantage rivals in a manner that causes the rivals' output to diminish or causes their behavior to become chastened. This "Type 11" collusion in turn allows the colluding firms to raise prices.3 Many important collusion cases, however, do not fit into either of these categories. -
Comparative Statics and Perfect Foresight in Infinite Horizon Economies
Digitized by the Internet Archive in 2011 with funding from Boston Library Consortium IVIember Libraries http://www.archive.org/details/comparativestatiOOkeho working paper department of economics Comparative Statics And Perfect Foresight in Infinite Horizon Economies Timothy J. Kehoe David K. Levine* Number 312 December 1982 massachusetts institute of technology 50 memorial drive Cambridge, mass. 02139 Comparative Statics And Perfect Foresight in Infinite Horizon Economies Timothy J. Kehoe David K. Levine* Number 312 December 1982 Department of Economics, M.I.T. and Department of Economics, U.C.L.A., respectively. Abstract This paper considers whether infinite horizon economies have determinate perfect foresight equilibria. ¥e consider stationary pure exchange economies with both finite and infinite numbers of agents. When there is a finite number of infinitely lived agents, we argue that equilibria are generically determinate. This is because the number of equations determining the equilibria is not infinite, but is equal to the number of agents minus one and must determine the marginal utility of income for all but one agent. In an overlapping generations model with infinitely many finitely lived agents, this reasoning breaks down. ¥e ask whether the initial conditions together with the requirement of convergence to a steady state locally determine an equilibrium price path. In this framework there are many economies with isolated equilibria, many with continue of equilibria, and many with no equilibria at all. With two or more goods in every period not only can the price level be indeterminate but relative prices as well. Furthermore, such indeterminacy can occur whether or not there is fiat money in the economy. -
Collusion Constrained Equilibrium
Theoretical Economics 13 (2018), 307–340 1555-7561/20180307 Collusion constrained equilibrium Rohan Dutta Department of Economics, McGill University David K. Levine Department of Economics, European University Institute and Department of Economics, Washington University in Saint Louis Salvatore Modica Department of Economics, Università di Palermo We study collusion within groups in noncooperative games. The primitives are the preferences of the players, their assignment to nonoverlapping groups, and the goals of the groups. Our notion of collusion is that a group coordinates the play of its members among different incentive compatible plans to best achieve its goals. Unfortunately, equilibria that meet this requirement need not exist. We instead introduce the weaker notion of collusion constrained equilibrium. This al- lows groups to put positive probability on alternatives that are suboptimal for the group in certain razor’s edge cases where the set of incentive compatible plans changes discontinuously. These collusion constrained equilibria exist and are a subset of the correlated equilibria of the underlying game. We examine four per- turbations of the underlying game. In each case,we show that equilibria in which groups choose the best alternative exist and that limits of these equilibria lead to collusion constrained equilibria. We also show that for a sufficiently broad class of perturbations, every collusion constrained equilibrium arises as such a limit. We give an application to a voter participation game that shows how collusion constraints may be socially costly. Keywords. Collusion, organization, group. JEL classification. C72, D70. 1. Introduction As the literature on collective action (for example, Olson 1965) emphasizes, groups often behave collusively while the preferences of individual group members limit the possi- Rohan Dutta: [email protected] David K. -
Interim Correlated Rationalizability
Interim Correlated Rationalizability The Harvard community has made this article openly available. Please share how this access benefits you. Your story matters Citation Dekel, Eddie, Drew Fudenberg, and Stephen Morris. 2007. Interim correlated rationalizability. Theoretical Economics 2, no. 1: 15-40. Published Version http://econtheory.org/ojs/index.php/te/article/view/20070015 Citable link http://nrs.harvard.edu/urn-3:HUL.InstRepos:3196333 Terms of Use This article was downloaded from Harvard University’s DASH repository, and is made available under the terms and conditions applicable to Other Posted Material, as set forth at http:// nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of- use#LAA Theoretical Economics 2 (2007), 15–40 1555-7561/20070015 Interim correlated rationalizability EDDIE DEKEL Department of Economics, Northwestern University, and School of Economics, Tel Aviv University DREW FUDENBERG Department of Economics, Harvard University STEPHEN MORRIS Department of Economics, Princeton University This paper proposes the solution concept of interim correlated rationalizability, and shows that all types that have the same hierarchies of beliefs have the same set of interim-correlated-rationalizable outcomes. This solution concept charac- terizes common certainty of rationality in the universal type space. KEYWORDS. Rationalizability, incomplete information, common certainty, com- mon knowledge, universal type space. JEL CLASSIFICATION. C70, C72. 1. INTRODUCTION Harsanyi (1967–68) proposes solving games of incomplete -
Tacit Collusion in Oligopoly"
Tacit Collusion in Oligopoly Edward J. Green,y Robert C. Marshall,z and Leslie M. Marxx February 12, 2013 Abstract We examine the economics literature on tacit collusion in oligopoly markets and take steps toward clarifying the relation between econo- mists’analysis of tacit collusion and those in the legal literature. We provide examples of when the economic environment might be such that collusive pro…ts can be achieved without communication and, thus, when tacit coordination is su¢ cient to elevate pro…ts versus when com- munication would be required. The authors thank the Human Capital Foundation (http://www.hcfoundation.ru/en/), and especially Andrey Vavilov, for …nancial support. The paper bene…tted from discussions with Roger Blair, Louis Kaplow, Bill Kovacic, Vijay Krishna, Steven Schulenberg, and Danny Sokol. We thank Gustavo Gudiño for valuable research assistance. [email protected], Department of Economics, Penn State University [email protected], Department of Economics, Penn State University [email protected], Fuqua School of Business, Duke University 1 Introduction In this chapter, we examine the economics literature on tacit collusion in oligopoly markets and take steps toward clarifying the relation between tacit collusion in the economics and legal literature. Economists distinguish between tacit and explicit collusion. Lawyers, using a slightly di¤erent vocabulary, distinguish between tacit coordination, tacit agreement, and explicit collusion. In hopes of facilitating clearer communication between economists and lawyers, in this chapter, we attempt to provide a coherent resolution of the vernaculars used in the economics and legal literature regarding collusion.1 Perhaps the easiest place to begin is to de…ne explicit collusion. -
Imbalanced Collusive Security Games
Imbalanced Collusive Security Games Han-Ching Ou, Milind Tambe, Bistra Dilkina, and Phebe Vayanos Computer Science Department, University of Southern California {hanchino,tambe,dilkina,phebe.vayanos }@usc.edu Abstract. Colluding adversaries is a crucial challenge for defenders in many real-world applications. Previous literature has provided Collusive Security Games (COSG) to model colluding adversaries, and provided models and algorithms to generate defender strategies to counter colluding adversaries, often by devising strategies that inhibit collusion [6]. Unfortunately, this previous work focused exclusively on situations with perfectly matched adversaries, i.e., where their rewards were symmetrically distributed. In the real world, however, defenders often face adversaries where their rewards are asymmetrically distributed. Such inherent asymmetry raises a question as to whether human adversaries would at- tempt to collude in such situations, and whether defender strategies to counter such collusion should focus on inhibiting collusion. To address these open ques- tions, this paper: (i) explores and theoretically analyzes Imbalanced Collusive Security Games (ICOSG) where defenders face adversaries with asymmetrically distributed rewards; (ii) conducts extensive experiments of three different adver- sary models involving 1800 real human subjects and (iii) derives novel analysis of the reason behind why bounded rational attackers models outperform perfectly rational attackers models. The key principle discovered as the result of our -
Econstor Wirtschaft Leibniz Information Centre Make Your Publications Visible
A Service of Leibniz-Informationszentrum econstor Wirtschaft Leibniz Information Centre Make Your Publications Visible. zbw for Economics Stähler, Frank Working Paper — Digitized Version Markov perfection and cooperation in repeated games Kiel Working Paper, No. 760 Provided in Cooperation with: Kiel Institute for the World Economy (IfW) Suggested Citation: Stähler, Frank (1996) : Markov perfection and cooperation in repeated games, Kiel Working Paper, No. 760, Kiel Institute of World Economics (IfW), Kiel This Version is available at: http://hdl.handle.net/10419/46946 Standard-Nutzungsbedingungen: Terms of use: Die Dokumente auf EconStor dürfen zu eigenen wissenschaftlichen Documents in EconStor may be saved and copied for your Zwecken und zum Privatgebrauch gespeichert und kopiert werden. personal and scholarly purposes. Sie dürfen die Dokumente nicht für öffentliche oder kommerzielle You are not to copy documents for public or commercial Zwecke vervielfältigen, öffentlich ausstellen, öffentlich zugänglich purposes, to exhibit the documents publicly, to make them machen, vertreiben oder anderweitig nutzen. publicly available on the internet, or to distribute or otherwise use the documents in public. Sofern die Verfasser die Dokumente unter Open-Content-Lizenzen (insbesondere CC-Lizenzen) zur Verfügung gestellt haben sollten, If the documents have been made available under an Open gelten abweichend von diesen Nutzungsbedingungen die in der dort Content Licence (especially Creative Commons Licences), you genannten Lizenz gewährten Nutzungsrechte. may exercise further usage rights as specified in the indicated licence. www.econstor.eu Kieler Arbeitspapiere Kiel Working Papers Kiel Working Paper No. 760 Markov perfection and cooperation in repeated games by Frank Stahler August 1996 Institut fur Weltwirtschaft an der Universitat Kiel The Kiel Institute of World Economics ISSN 0342 - 0787 The Kiel Institute of World Economics Diisternbrooker Weg 120 D-24105Kiel, FRG Kiel Working Paper No. -
Network Markets and Consumer Coordination
NETWORK MARKETS AND CONSUMER COORDINATION ATTILA AMBRUS ROSSELLA ARGENZIANO CESIFO WORKING PAPER NO. 1317 CATEGORY 9: INDUSTRIAL ORGANISATION OCTOBER 2004 PRESENTED AT KIEL-MUNICH WORKSHOP ON THE ECONOMICS OF INFORMATION AND NETWORK INDUSTRIES, AUGUST 2004 An electronic version of the paper may be downloaded • from the SSRN website: www.SSRN.com • from the CESifo website: www.CESifo.de CESifo Working Paper No. 1317 NETWORK MARKETS AND CONSUMER COORDINATION Abstract This paper assumes that groups of consumers in network markets can coordinate their choices when it is in their best interest to do so, and when coordination does not require communication. It is shown that multiple asymmetric networks can coexist in equilibrium if consumers have heterogeneous reservation values. A monopolist provider might choose to operate multiple networks to price differentiate consumers on both sides of the market. Competing network providers might operate networks such that one of them targets high reservation value consumers on one side of the market, while the other targets high reservation value consumers on the other side. Firms can obtain positive profits in price competition. In these asymmetric equilibria product differentiation is endogenized by the network choices of consumers. Heterogeneity of consumers is necessary for the existence of this type of equilibrium. JEL Code: D43, D62, L10. Attila Ambrus Rossella Argenziano Department of Economics Department of Economics Harvard University Yale University Cambridge, MA 02138 New Haven, CT 06520-8268