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Selection, Learning, and Nomination: Essays on Supermodular Games, Design, and Political Theory


Mathevet, Laurent Alexandre (2008) Selection, Learning, and Nomination: Essays on Supermodular Games, Design, and Political Theory. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/BQAQ-KV91.


Games with strategic complementarities (GSC) possess nice properties in terms of learning and structure of the equilibria. Two major concerns in the theory of GSC and mechanism design are addressed. Firstly, complementarities often result in multiple equilibria, which requires a theory of equilibrium selection for GSC to have predictive power. Chapter 2 deals with global games, a selection paradigm for GSC. I provide a new proof of equilibrium uniqueness in a wide class of global games. I show that the joint best-response in these games is a contraction. The uniqueness result then follows as a corollary of the contraction principle. Furthermore, the contraction-mapping approach provides an intuition for why uniqueness arises: complementarities generate multiple equilibria, but the global-games structure dampens complementarities until one equilibrium survives. Secondly, there is a concern in mechanism design about the assumption of equilibrium play. Chapter 3 examines the problem of designing mechanisms that induce supermodular games, thereby guiding agents to play desired equilibrium strategies via learning. In quasilinear environments, I prove that if a scf can be implemented by a mechanism that generates bounded substitutes - as opposed to strategic complementarities - then this mechanism can be converted into a supermodular mechanism that implements the scf. If the scf also satisfies some efficiency criterion, then it admits a supermodular mechanism that balances budget. Then I provide general sufficient conditions for a scf to be implementable with a supermodular mechanism whose equilibria are contained in the smallest interval among all supermodular mechanisms. I also give conditions for the equilibrium to be unique. Finally, a supermodular revelation principle is provided for general preferences. The final chapter is an independent chapter on political economics. It provides three different processes by which two political parties nominate candidates for a general election: Nominations by party leaders, by a vote of party members, and by a spending competition. It is shown that more extreme outcomes can emerge from spending competition and that non-median outcomes can result via any process. Under endogenous party membership, median outcomes ensue when nominations are decided by a vote but not with spending competition.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:complementarities; contraction; global games; implementation; learning; mechanisms; nomination; political parties; supermodularity; uniqueness
Degree Grantor:California Institute of Technology
Division:Humanities and Social Sciences
Major Option:Social Science
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Echenique, Federico (advisor)
  • Jackson, Matthew O. (advisor)
Thesis Committee:
  • Echenique, Federico (co-chair)
  • Jackson, Matthew O. (co-chair)
  • Yariv, Leeat
  • McAfee, R. Preston
Defense Date:15 May 2008
Non-Caltech Author Email: lmath (AT)
Record Number:CaltechETD:etd-05282008-122413
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:2210
Deposited By: Imported from ETD-db
Deposited On:04 Jun 2008
Last Modified:27 Nov 2019 18:36

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