Northwestern University mathematics professor Don
Saari gave a lecture at Purdue on Thursday, April 11, in conjunction with Math Awareness Week.
Professor Saari spoke about the mathematics of voting theory.
Does voting need a theory, and is mathematics needed to study it? The
answer is yes, once we realize that our traditional majority voting
system can lead to some conundrums. For example, in a three way race, if
one of the candidates is favored by a plurality of the voters, but is
ranked dead last by a majority, does that candidate deserve to win?
Consider a presidential race with one left of center candidate, and two
right of center, or a mayoral race with one white candidate, and two
black; does this sound familiar? Voting theory allows for many different
kinds of voting procedures (e.g., Borda count, approval voting, plurality
voting), and these different procedures will, given the same voter
preferences, determine different outcomes. (Those of you who followed
the Lani Guinier nomination a couple of years ago may recall that one of
the things that got her into trouble was her consideration in print of
some of these alternate voting systems.) Professor Saari has used
mathematics to analyze these different voting processes to try and
determine which one leads to the fewest "paradoxes." His results are
new, surprising, and provocative.

Professor Saari is a very good speaker,
a natural story teller, and an award winning writer; he has received the
two highest prizes given by the math community for expository writing, the
L. R. Ford Award (1985) and the Chauvenet Prize (1995). The work
described in this talk is interdisciplinary, and so it should appeal to
students in many fields, for example, political science, sociology,
management, economics, history.
If you would like to read a bit more about Professor Saari's work, visit his home page at:

http://www.math.nwu.edu/~d_saari/