Combinatorics Seminar
When: Sunday, November 27, 10am
Where: Schreiber 309
Speaker: Ehud Friedgut, Hebrew University
Title: A range of robust social choice results
Abstract:
The celebrated Arrow's theorem states that it's impossible
for a non-dictatorial society to rank a set of candidates under
certain reasonable restrictions. In the same spirit the
Gibbard-Satterthwaite theorem states impossibility even when
the task is choosing a single alternative.
In this talk I'll present a range of results that bridge these two
extreme states (e.g. impossibility of choosing a president, a vice
president, and an non-ranked cabinet of 5 additional ministers).
Our results also include robustness - any system that "almost"
fulfills the restrictions is "almost" dictatorial.
The techniques are spectral, and involve representation theory of
the symmetric group.
Joint work with Dvir Falik.