What Questions to Ask in Voting with Partial Information

PhD Thesis Proposal Defence


Title: "What Questions to Ask in Voting with Partial Information"

by

Mr. Ning DING


ABSTRACT:

Voting is a way to aggregate individual voters' preferences. Traditionally 
a voter's preference is represented by a total order on the set of 
candidates. However, sometimes one may not have complete information about 
a voter's preference, and in this case, can only model a voter's 
preference as a partial order. Given this framework, there has been work 
on computing the possible and necessary winners of a (partial) profile. In 
this proposal, we extend the concept of partial profile to include the 
more general partial information about a voter's preference. We also take 
a step further, look at sets of questions to ask in order to determine the 
outcome of such a partial profile. Specifically, we call a set of 
questions a deciding set for a candidate if the outcome of the vote for 
the candidate is determined no matter how the questions are answered by 
the voters, and a possible winning (losing) set if there is a way to 
answer these questions to make the candidate a winner (loser) of the vote. 
We discuss some interesting properties about these sets of queries, prove 
some complexity results about them under some well-known voting rules such 
as plurality and Borda, and consider their application in vote 
elicitation. We also discuss the properties of different forms of 
questions. Some question sets have a unique minimal deciding set in any 
partial profile under certain voting rules. We believe this implies that 
the question set is proper for the voting rule. So we further discuss what 
kind of questions sets has a unique minimal deciding set in any partial 
profile under any voting rule. And we give examples of question sets and 
voting rules that have a unique minimal deciding set in any partial 
profile, and examples that does not. We take plurality as an example to 
illustrate the usefulness of minimal deciding sets in vote elicitation.


Date:                   Friday, 19 April 2013

Time:                   3:00pm - 5:00pm

Venue:                  Room 5506
                         lifts 25/26

Committee Members:      Prof. Fangzhen Lin (Supervisor)
                         Prof. Mordecai Golin (Chairperson)
 			Dr. Lei Chen
 			Dr. Ke Yi


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