They also link us, often through important but weak ties, to other humans. Their origin is biological: going back to quorum-sensing, swarming, flocking, social grooming, gossip, etc. Yet, as we have connected our social networks to traditional human institutions (markets, justice systems, education, etc.) through new technologies, the underlying biology has become obscured, but not dormant.
Economic markets also look much more like networks than anonymous marketplaces. Firms interact with the suppliers and customers in a Web-like supply chains. Systemic risk in financial markets often results from the counterparty risks created within this financial network.
This course will introduce the tools for the study of networks. It will show how certain common principles permeate the functioning of these diverse networks: e.g., issues related to robustness, fragility, and interlinkages etc.
(1) Introduction to networks (Social, Economic and Communication)
(2) Biology of Social Networks
(3) Graph theory and social networks
Directed and undirected graphs, paths, cycles, diameter, clustering, bipartite graphs. Applications: the web as a directed graph, homophily.
(4) Random graph models
Review of branching processes, Erdos-Renyi graphs, degree distributions, 0-1 Laws, connectedness, and giant component. Applications: tipping, six degrees of separation, and disease transmissions.
(5) Preferential attachment, power laws, and small worlds
Preferential attachment, degree distributions, generalized random graphs, and clustering. Applications: firm size distributions, link analysis and web search, PageRank, decentralized search, and navigation.
(6) Game theory
Games, strategies, payoffs, extensive and normal forms, and Nash equilibrium. Applications: tragedy of the commons and coordination games.
(7) Communication and Signaling
Evolution of Languages in Network, Decoding. Applications: Language of Twitter.
(8) Decisions in groups
Decision making in organizations and societies, social choice, Condorcet jury theorem, and political economy. Application: committee decisions.
(9) Macro-Economic Models and Supply-Chains
(9) Case Studies:
Facebook, ATTAP, Twitter, Wikileaks, Bit-coins, Arab Spring, Occupy Wallstreet