The  Weizmann  Institute  of  Science
                  Faculty of Mathematics and Computer Science
 
                    Foundations of Computer Science Seminar
 
                     Lecture Hall, Room 1, Ziskind Building
                          on Sunday, January 30, 2011
                                    at 11:00
 
                          Note unusual day/time/location 
 
                                 Yoram Bachrach
                         Microsoft Research, Cambridge
 
                                 will speak on
 
                      Conspiracies, Cooperation and Power
 
Abstract:
Cooperative game theory is all about how selfish agents might agree to
collaborate and then share their spoils. It allows answering questions such
as:
 
Would the political power balance change if a big party decided to split into
two smaller parties?
 
Can selfish behavior jeopardize making mutually beneficial agreements?
 
How might pirates share a hidden treasure when they need each other to find
it?
 
Cooperation can be problematic when agents collaborate to attack an economic or
political system. For example, agents participating in an auction can
coordinate their bids in order to pay less for obtaining their items and
political parties may strategically merge or split to increase their
influence.  This talk examines computational aspects of such phenomena,
focusing on collusion in auctions and attacks in decision making bodies.
 
Auctions based on the VCG mechanism are excellent in achieving truthful bids
and an optimal allocation when agents do not collude.
 
However, they are very susceptible to collusion. I will demonstrate this in
multi-unit auctions and path procurement auctions, showing how the colluders
can compute their optimal joint bidding strategy and reasonable agreements for
sharing the gains.
 
I will then consider attacks in weighted voting games, a known model for
cooperation between agents in decision-making bodies, showing how agents can
compute strategies that increase their power.
 
The analysis for both domains is based on the core and the Shapley value,
prominent solution concepts from cooperative game theory.
 
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Technion Math Net-2 (TECHMATH2)
Editor: Michael Cwikel   <techm@math.technion.ac.il> 
Announcement from: Diana Mandelik   <diana.mandelik@weizmann.ac.il>