7 December 2012, Computational Social Choice Seminar, Jan van Eijck
The Gibbard-Satterthwaite Theorem says that every reasonable votingrule can be manipulated, provided that there are at least threealternatives to choose from. What this means is that voting is agame, and that game theory can help to determine the individual andgroup strategies for getting as close as possible to a preferredoutcome. In this talk I will use the well-known action logic PDL(propositional dynamic logic) to model the Gibbard-SatterthwaiteTheorem. This sheds new light on the proof of the theorem, andsuggests new questions about the role of knowledge in strategicreasoning in voting.