BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//University of Liverpool Computer Science Seminar System//v2//EN
BEGIN:VEVENT
DTSTAMP:20260922T191601Z
UID:Seminar-dept-377@lxserverM.csc.liv.ac.uk
ORGANIZER:CN=Lutz Oettershagen:MAILTO:Lutz.Oettershagen@liverpool.ac.uk
DTSTART:20150428T130000
DTEND:20150428T140000
SUMMARY:School Seminar Series
DESCRIPTION:Prof. Stephane Airiau: Voting in parallel universes\n\nSome voting rules involve some tie-breaking in the course of an multi-stage process (this is notably the case for STV). For these rules, some authors have argued that there exists a version where ties are broken when they appear, and a 'parallel universe' where all ways of breaking ties at intermediate stages are considered (and, if necessary, ties are broken at the very end). A general framework for these rules had been discussed in (Freeman et al., 15), based on so-called 'computation trees'. Here we propose an alternative general framework, where each 'possible universe' corresponds to a priority ranking over candidates. We show that many other rules fall in this family (such as Banks and Top Cycle). We also consider two other classes of rules: stochastic rules, where the winning probability of a candidate is the ratio of tie-breaking orders for which it wins, and an 'argmax rule' that elects the candidates max- imizing this winning probability. We discuss several properties of these rules and discuss some complexity issues as well as simulation results.\n\nhttps://www.csc.liv.ac.uk/research/seminars/abstract.php?id=377
LOCATION:Ashton Lecture Theater
END:VEVENT
END:VCALENDAR