Networks & Games Webinar Series
Networks & Games (www.gamesnet.in) presents a webinar series on Game Theory and Network Theory.
Speaker: Prof Georges Zaccour, Chair in Game Theory and Management, HEC Montréal, Canada
Date: 30th September 2020
Time: 6.30PM India Time
Duration: 1 hour
Title: Sustainability of Cooperation in Dynamic Games Played over Event Trees
Abstract: Many problems in economics, engineering and management science have the following three features in common: (a) They involve only a few agents (players) who have interdependent payoffs. (b) The agents cooperate or compete repeatedly over time, and the problem involves an accumulation process, e.g., production capacity, pollution stock. (c) Some of the parameter values are uncertain. A natural framework to deal with such problems is the theory of dynamic games played over event trees (DGPETs). If the players decide to coordinate their strategies by signing a long-term contract, then they must ensure that all players follow their cooperative commitments as time goes by. In this talk, I discuss different approaches to sustain cooperation over time in DGPETs.
Author Bio: Georges Zaccour holds the Chair in Game Theory and Management and is full professor of Management Science at HEC Montréal. He holds a Ph.D. in management science, an M.Sc. in international business from HEC Montréal and a licence in mathematics and economics from Université Paris-Dauphine. He served as director of GERAD, marketing department and Ph.D. program at HEC Montréal. His research areas are differential games, optimal control and operations, areas in which he has published more than one hundred papers and co-edited thirteen volumes. He coauthors the books Differential Games in Marketing and Games and Dynamic Games (to appear). His research is regularly funded by the Natural Sciences and Engineering Research Council of Canada. He is editor-in-chief of Dynamic Games and Applications and associate editor for several journals. He is fellow of The Royal Society of Canada and was president of the International Society of Dynamic Games (2002-2006).
Lecture 12 (Watch the Video)
Speaker: Prof Rahul Roy, Professor at Indian Statistical Institute, New Delhi.
Date: 15th September 2020
Time: 6.30PM India Time
Duration: 1 hour
Authors: Arpan Mukhopadhyay, Ravi R. Mazumdar, & Rahul Roy
We study binary opinion dynamics in a fully connected network of interacting agents. The agents are assumed to interact according to one of the following rules:
(1) Voter rule: An updating agent simply copies the opinion of another randomly sampled agent;
(2) Majority rule: An updating agent samples multiple agents and adopts the majority opinion in the selected group.
We focus on the scenario where the agents are biased towards one of the opinions called the preferred opinion. Using suitably constructed branching processes, we show that under both rules the mean time to reach consensus is theta(logN),where N is the number of agents in the network. Furthermore, under the majority rule model, we show that consensus can be achieved on the preferred opinion with high probability even if it is initially the opinion of the minority. We also study the majority rule model when stubborn agents with fixed opinions are present. We find that the stationary distribution of opinions in the network in the large system limit using mean field techniques
Author Bio: Rahul Roy is a professor at the Indian Statistical Institute, New Delhi. He works in probability theory and, more particularly, in percolation theory and random graphs. He is also interested in the history of mathematics. He is a fellow of the Indian Academy of Sciences, and he obtained his Ph.D. from Cornell University. His book with Ronald Meester 'Continuum Percolation' is considered a classic in the domain.
Lecture 11 (Watch the Video)
Speaker: Prof Tamer Başar, Director, Center for Advanced Study, University of Illinois at Urbana-Champaign .
Date: 1st September 2020
Time: 9AM CDT (7.30PM India Time)
Duration: 1 hour
Title: Mean Field Differential Games with Elements of Robustness
Abstract: Mean field games (MFGs) constitute a class of non-cooperative stochastic differential games (SDGs) with a large number of players who interact with each other through a mean field coupling term, appearing in the individual cost functions and/or each player’s dynamics described by a controlled stochastic differential equation. One of the main research issues in MFGs is to study the existence, uniqueness and characterization of Nash equilibria with an infinite population of players under specified information structures and further to study finite-population approximations, that is to what extent an infinite-population Nash equilibrium (NE) provides an approximate NE for the finite-population game.
Following a general overview of the difficulties brought about by strategic interactions in finite-population SDGs, the talk will dwell on two classes of MFGs: those characterized by risk sensitive (RS) objective functions and those that have risk-neutral (RN) objective functions but with an additional adversarial driving term in the dynamics (known as robust MFGs). The talk will discuss the connection between these two classes of MFGs, particularly with linear-quadratic structures, which will allow for closed-form solutions and explicit comparisons between the two in both infinite- and finite-population regimes and with respect to the approximation of NE in going from the former to the latter. The talk will conclude with a brief discussion of several extensions of the framework.
Author Bio: Tamer Başar received the B.S.E.E. degree from Robert College, Istanbul, and M.S., M.Phil., and Ph.D. degrees from Yale University. He is with the University of Illinois at Urbana-Champaign, where he holds the academic positions of Swanlund Endowed Chair; Center for Advanced Study Professor of Electrical and Computer Engineering; Research Professor at the Coordinated Science Laboratory; and Research Professor at the Information Trust Institute. He was the Editor-in-Chief of Automatica between 2004 and 2014, and is currently editor of several book series. He is also the Director of the Center for Advanced Study. He is a member of the US National Academy of Engineering and the European Academy of Sciences; Fellow of IFAC, and SIAM; a past president of the IEEE Control Systems Society (CSS), the founding president of the International Society of Dynamic Games (ISDG), and a past president of the American Automatic Control Council (AACC). His current research interests include stochastic teams, games, and networks; multi-agent systems and learning; data-driven distributed optimization; spread of information and epidemics; security and trust; energy systems; and cyber-physical systems. He has received several awards and recognitions over the years, including the highest awards of IEEE CSS, IFAC, AACC, and ISDG, the IEEE Control Systems Award, and a number of International Honorary Doctorates and Professorships. He has over 900 publications in systems, control, communications, networks, optimization, and dynamic games, including books on non-cooperative dynamic game theory, robust control, network security, wireless and communication networks, and stochastic networked control.
Lecture 10 (Watch the video here)
Speaker: Prof Sudipta Sarangi, Department Head & Professor of Economics, Virginia Tech
Date: 20th August 2020
Time: 9AM Eastern Time (6.30PM India Time)
Duration: 1 hour
Title: Two Models of Multigraphs
Abstract: Economic agents are typically connected to others in multiple network relationships, and the architecture of one network could be shaped by connections in other networks. In this talk we explore two models of network formation with multiple networks. In the first model, we assume that one network is given and examine how its structure affects the formation of the other network. In the second model we use a degrees-based approach to study the formation of two networks simultaneously under different conditions.
Author Bio: Sudipta Sarangi is one of the founding members of GamesNet. His research interests lie in economic theory and its application to areas like networks, development economics and experimental economics. In 2020, he received the Kuznets Prize for his research on the historical origins of Gender Inequality. He serves on the editorial boards of Journal of Economic Behavior and Organization, Journal of Public Economic Theory, Economic Modelling and Studies in Microeconomics. He is a Research Associate of DIW Berlin, GATE, University of Lyon-St. Etienne and the Lima School of Economics. Previously he has worked at the National Science Foundation and was a Distinguished Professor of Business Administration at Louisiana State University. He is currently Department Head and Professor of Economics at Virginia Tech. His book The Economics of Small Things will be published by Penguin India in November 2020.
Lecture 9 (Watch the video here)
Speaker: Prof. Sanjeev Goyal, Professor of Economics and a Fellow of Christ's College, Cambridge
Date: 4th August 2020
Time: 2PM BST (6.30PM India Time)
Duration: 1 Hour
Title: Large Scale Experiments on Networks: A New Platform with Applications
Authors: Choi, S., Goyal, G. and Moisan, F.
Abstract: This paper presents a new platform for large scale networks experiments in continuous time. The versatility of the platform is illustrated through three experiments: a game of linking, a linking game with public goods, and a linking game with trading and intermediation. Group size ranges from 8 to 100 subjects. These experiments reveal that subjects create sparse networks that are almost always highly efficient. In some experiments the networks are centralized and unequal, while in others they are dispersed and equal. These network structures are in line with theoretical predictions, suggesting that continuous time asynchronous choice facilitates a good match between experimental outcomes and theory. The size of the group has powerful effects on individual investments in linking and effort, on network structure, and on the nature of payoff inequality. Researchers should therefore exercise caution in drawing inferences about behaviour in large scale networks based on data from small group experiments.
Author Bio: Sanjeev Goyal is Professor of Economics and a Fellow of Christ's College, Cambridge. He got his BA from the University of Delhi, his MBA from IIM Ahmedabad, and his Ph.D from Cornell University. He has previously held Chairs at Erasmus University Rotterdam, University of London, and Essex University, and was Wesley Clair Mitchell Visiting Professor at Columbia University in Spring, 2020.
He is a pioneer and leading international scholar in the study of networks. His book, `Connections: an introduction to the economics of networks`, was published in 2007 by Princeton University Press. A Chinese translation appeared in 2010.
He is a Fellow of the British Academy, a Fellow of the Econometric Society, and a member of the Council of the Game Theory Society. He was the Founding Director of the Cambridge-INET Institute (2012-2014) and Chair of the Economics Faculty at Cambridge, 2014-2018.
Lecture 8 (Watch the video here)
Speaker: Prof. Adam Dominiak, Associate Professor of Economics at Virginia Tech
Date: 21st July 2020
Time: 10AM EST (7.30PM India Time)
Duration: 1.5 Hour (Note the longer duration)
Title: Decision Making Under Ambiguity
Authors: Adam Dominiak
Abstract: Ambiguity refers to choice situations under uncertainty with unknown probabilities of states. Ambiguity is ubiquitous in the real world. Daniel Ellsberg introduced ambiguity into economics in his seminal 1961 article. In a series of elegant thought-experiments, he conjectured that individuals might be ambiguity averse; i.e., they might prefer betting on states with known probabilities rather than betting on states with unknown probabilities. Ambiguity aversion violates the classical models of choice that rely on the hypothesis that individuals’ beliefs can be represented by a unique probability distribution. Nowadays ambiguity aversion is a well-documented behavior. Many formal models have been developed in order to accommodate the phenomena of ambiguity and ambiguity aversion into economic theory. This survey provides a brief review of the popular ambiguity models. Starting with the classical Subjective Expected Utility (SEU) theory of Leonard Savage and the Ellsberg paradox, it presents three extensions of SEU with different representations of ambiguity and ambiguity aversion. It continues with an economic application. Finally, it discusses some extensions of ambiguity models to dynamic choice problems.
Author Bio: Adam Dominiak is currently an Associate Professor of Economics at Virginia Tech with research interests in areas of Decision Theory, Game Theory, Experimental Economics, Behavioral Economics, and Epistemic Game Theory.
He obtained his PhD from the University of Heidelberg and has been a visiting professor at UC Davis, Kellogg School of Management and Paris-Dauphine University. He has published in the top theory journals like Games and Economic Behavior, Economic Theory, Management Science and Journal of Mathematical Economics. He is currently the Guest Editor of a Special Issue of Theory and Decision in honor of Jurgen Eichberger.
Lecture 7 (Watch the video here)
Speaker: Prof. Michel Grabisch, Professor of Computer Sciences at Université Paris I Panthéon-Sorbonne and Associated Professor at Paris School of Economics
Date: 7th July 2020
Time: 3PM CEST (6.30PM India Time)
Duration: 1 Hour
Title: Opinion dynamics: a survey
Authors: Michel Grabisch
Abstract: With the development of network theory, there is a huge literature on how opinion in a society of agents is evolving, due to interactions between agents. While sociologists have initiated many fundamental models, other disciplines have significantly contributed to the field: economists have incorporated strategic considerations, physicists have considered agents as particles and created sociophysics, computer scientists treated agents as automata, and control theorists have considered the dynamics of opinion as a particular input/output system. This short survey focuses on nonstrategic models, considering either that opinion is a binary (yes/no), or is continuous. Starting from classical models (essentially the threshold model for binary opinion, and the DeGroot model for continuous opinion), it shows the main variants of them, putting emphasis on two aspects which are of recent interest: anti-conformity behavior, and time-varying models.
Author Bio: Michel Grabisch started his career as research engineer at Thomson-CSF, and is since 2002 full professor of computer sciences at Université Paris I Panthéon-Sorbonne and associated professor at Paris School of Economics. He is the head of the Theoretical MicroEconomics group at Centre d'Economie de la Sorbonne and honorary senior member of the Institut Universitaire de France.
His research interests are game theory, decision theory, networks and opinion formation, and discrete mathematics. He has authored and co-authored more than 120 papers in refereed international journals, 5 books, and more than 100 papers in refereed international conferences. He is co-editor-in-chief of 4OR, and associate editor of Annals of Operations Research, Mathematical Social Sciences, Order and several other journals.
Lecture 6 (Watch the video here, Download presentation)
Speaker: Prof. Herve Moulin, Donald J. Robertson Chair of Economics at the Adam Smith Business School at the University of Glasgow
Meeting ID: 884 8110 9223
Date: 23rd June 2020
Time: 2PM BST (GMT +1, 6.30PM India Time)
Duration: 1 Hour
Title: Fair Division with Money
Authors: Anna Bogomolnaia and Herve Moulin
Agents share indivisible objects (desirable or not) and use cash transfers to achieve fairness. Utilities are linear in money but otherwise arbitrary. We look for n-person division rules preserving the informational simplicity of Divide and Choose or the Texas Shoot Out between two agents, treating agents symmetrically, and offering high individual welfare Guarantees.
A single bidding for the whole manna is one such method but it does not capture the potential efficiency gains from debundling the objects as in Divide and Choose. Our Bid and Choose rules fix a benchmark price p for the objects; in each of the n-1 rounds of bidding the winner must pay for the remaining objects he picks. These rules are much simpler than Kuhn's n-person generalisation of Divide and Choose, and they typically offer better Guarantees. They help agents with subadditive utilities, to the detriment of those with superadditive utilities.
Author Bio: Hervé Moulin is the Donald J. Robertson Chair of Economics at the Adam Smith Business School at the University of Glasgow. He is known for his research contributions in mathematical economics, in particular in the fields of mechanism design, social choice, game theory and fair division. He has written six books and over 100 peer-reviewed articles. Before joining the University of Glasgow, he was the George A. Peterkin Professor of Economics at Rice University (from 1999 to 2013), the James B. Duke Professor of Economics at Duke University (from 1989 to 1999) and the University Distinguished Professor at Virginia Tech (from 1987 to 1989).
He is a fellow of the Econometric Society since 1983, and the President of the Game Theory Society since 2018. He also served as president of the Society for Social Choice and Welfare for the period of 1998 to 1999. He is a fellow of the Royal Society of Edinburgh. He is also a Fellow of the British Academy.
Moulin obtained his doctoral degree in Mathematics at the University of Paris in 1975 with a thesis on zero-sum games, which was published in the Journal of Mathematical Analysis and its Applications. On 1979, he published a seminal paper in Econometrica introducing the notion of dominance solvable games. His work on this concept was mentioned in Eric Maskin's Nobel Prize Lecture. Moulin is credited as the first proposer of the famous beauty contest game. Experiments testing the equilibrium prediction of this game started the field of experimental economics.
Lecture 5 (Watch the video here)
Speaker: Prof. Juan D Moreno-Ternero, Professor at the Department of Economics, University Pablo de Olavide (Seville)
Meeting ID: 838 2125 5038
Date: 11th June 2020
Time: 3PM CEST (GMT +2, 6.30PM India Time)
Duration: 1 Hour
Title: Fair international protocols for the abatement of Greenhouse Gas (GHG) emissions
Authors: Biung-Ghi Ju, Min Kim, Suyi Kim, Juan D. Moreno-Ternero
Abstract: We study the design of fair international protocols for the abatement of GHG emissions. We formulate normative principles, pertaining to countries’ population, emission history, and (business as usual) future emissions, as axioms for allocation rules. We show that combinations of these axioms characterize the so-called equal per capita allocation rules, with or without historical accountability. The allocations these rules generate are in stark contrast with the allocation suggested by the Kyoto protocol, which is close to the allocation in proportion to the current and business-as-usual emissions, suggested by the proportional (grandfathering) rule. As we illustrate, equal per capita allocations admit more emissions to developing countries with large populations. And, with historical accountability, developed countries with large historical emissions are clearly penalized.
Author Bio: Juan D. Moreno-Ternero is a Professor at the Department of Economics, University Pablo de Olavide (Seville) and an Affiliate Research Fellow at the Seoul National University Center for Distributive Justice. He holds a Ph.D. in Economics from the University of Alicante and was a Postdoctoral Fellow at the Department of Political Science, Yale University, and at CORE, Université catholique de Louvain. His research interests include distributive justice, welfare economics, health economics, and political economy. He has published some 40 articles on these topics in journals such as Econometrica, Management Science, International Economic Review, Games and Economic Behavior, or Journal of Health Economics. He currently serves as co-Editor of the journals Mathematical Social Sciences, and SERIEs (Journal of the Spanish Economic Association), as well as Associate Editor of Economic Theory and Economic Theory Bulletin.
Speaker: Prof. Kaushik Basu, Professor of Economics and the Carl Marks Professor of International Studies at Cornell University
Meeting ID: 933 3347 9912
Date: 2nd June 2020
Time: 9.30AM EDT (GMT - 4, 7PM India Time)
Duration: 1 Hour
Title: The Samaritan’s Curse: Moral Individuals and Immoral Groups
Abstract: The paper revisits the question of how and in what sense can individuals comprising a group be held responsible for morally reprehensible behavior by that group. The question is tackled by posing a counterfactual: what would happen if selfish individuals became moral creatures, instead? A new game, the Samaritan’s Curse, is introduced, which sheds light on the moral philosopher’s dilemma of group moral responsibility, but also opens up new questions concerning conferred morality and self-fulfilling morals, and implicit assumptions in game-theoretic arguments.
Author Bio: Kaushik Basu is Professor of Economics and the Carl Marks Professor of International Studies at Cornell University, and former Chief Economist of the World Bank (2012-16). From December 2009 to July 2012 he served as the Chief Economic Advisor to the Government of India. Earlier he was Professor of Economics at the Delhi School of Economics, where in 1992 he founded the Centre for Development Economics and was its first Executive Director. He is a Fellow of the Econometric Society and has received several honorary degrees, including doctorates from IIT Bombay, and Fordham University, New York. He is the author of several books, the most recent being The Republic of Beliefs: A New Approach to Law Economics (Princeton University Press, 2018). In May 2008, he was awarded one of India’s highest civilian awards, the Padma Bhushan, by the President of India.
Lecture 3 (Watch the video here)
Speaker: Prof. Kalyan Chatterjee, Distinguished Professor of Economics and Management Science at Penn State University
Date: 19th May 2020
Time: 9AM Eastern Time (GMT - 5, 6.30PM India Time)
Duration: 1 Hour
Title: Competition and price formation
Abstract: In this talk, I discuss some past work, including some of my own with co-authors, on modelling the fine structure of small markets. The focus is on understanding whether the pressure of competition drives prices of the same goods in different markets to be identical. Auctions and markets in which transactions are bilateral are two examples. Price dispersion is also discussed. The presentation is for general audiences, but is based on economic theory. It was given as one of the RC Dutt Memorial Lectures at the Centre for Studies in Social Sciences at Kolkata a few years ago.
Author Bio: Kalyan Chatterjee holds the title of Distinguished Professor of Economics and Management Science at Penn State University. He graduated in Physics from Presidency College, then studied at IIM Kolkata before getting a DBA from Harvard University. His research interests cover game theory and its applications in industrial organization and R&D models, decision theory, bargaining and negotiation-models and experiments, coalition formation and stability, incomplete contracts, complexity of strategies in games, economics of social networks. He has published in all the top journals and has served as the Chair for 42 doctoral students. Prof. Chatterjee is a Fellow of the Econometric Society, Member of the Institute for Advanced Study at Princeton University and has a long list of other honors.
Lecture 2 (Watch the video here)
Speaker: Prof. Benjamin Golub, Department of Economics, Harvard University
Date: 5th May 2020
Time: 7AM Eastern Time (GMT - 5, 4.30PM India Time)
Duration: 1 Hour
Abstract: We model the production of complex goods in a large supply network. Firms source several essential inputs through relationships with other firms. Due to the risk of such supply relationships being idiosyncratically disrupted, firms multisource inputs and invest to make relationships with suppliers stronger. In equilibrium, aggregate production is robust to idiosyncratic disruptions. However, depending on parameters, the supply network may be robust or arbitrarily sensitive to small aggregate shocks that affect the functioning of relationships. We give conditions under which the equilibrium network is driven to a fragile configuration, where arbitrarily small aggregate shocks cause discontinuous losses. We use the model to provide a unified account of a number of stylized facts about complex economies.
Author Bio: Benjamin Golub’s research in economic theory focuses on social and economic networks. Since 2015, Ben has been on the faculty at the Harvard Department of Economics, where he is now Associate Professor; prior to that he spent two years as a Junior Fellow (2013-15) at the Harvard Society of Fellows. He has received the NSF CAREER grant (2019) and the Aliprantis Prize (2012) with Matt Elliott for an outstanding paper by a young economic theorist. He was educated at Stanford (Ph.D. in economics) and Caltech (B.S., mathematics).
Speaker: Prof. Francis Bloch, Paris School of Economics
Date: 21st April 2020
Time: 3PM Paris Time (GMT + 2, 6.30PM India Time)
Duration: 1 Hour
Abstract: We propose and study a strategic model of hiding in a network, where the network designer chooses the links and his position in the network facing the seeker who inspects and disrupts the network. We characterize optimal networks for the hider, as well as equilibrium hiding and seeking strategies on these networks. We show that optimal networks are either equivalent to cycles or variants of a core-periphery networks where every node in the periphery is connected to a single node in the core.