Type: Seminar

Distribution: World

Expiry: 24 May 2013

CalTitle1: AGR Seminar: Abelian groups: their role in the pathological behaviour of braids and the downfall of democracy!

Auth: mathas@pmathas.pc (assumed)

**Host venue**

RMIT

**Abstract**

A famous theorem in social choice theory, due to Kenneth Arrow, says that there is no "reasonable" system for combining preference orders. For example, in an election we may want a system for taking the voters' various rankings of the candidates in order of preference and obtaining a single ranking of the candidates. I will discuss an unexpected connection between Arrow's Theorem and my research into braids (a kind of partially ordered set). Indeed, my study of braids led to a theorem about finite abelian groups that can be applied to simplify the proof of Arrow's Theorem; a surprising interconnection between three apparently quite different parts of mathematics. The talk will be aimed at a general audience and will assume nothing other than some elementary facts about abelian groups.

**Seminar convenor**

Dr Sergei Schreider

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If you would like to attend this seminar in our access grid room then please check to see if the grid is already booked at this time and send an email to accessgridroom@maths.usyd.edu.au to let the CSOs know that you would like to attend.