What is Arrow’s Theorem?

The SCHOOL OF PHYSICAL SCIENCES, Discipline of Mathematics presents:
A talk by Dr Barry Gardner
There is no Nobel Prize for Mathematics, but people have won the Nobel Prize for Economics by doing mathematical work, e.g. John Nash, he of the beautiful mind, and Kenneth Arrow, who in 1950 published a theorem which shows, in effect, that a perfect electoral system is impossible. More specifically, Arrow showed that a list, a very short list, of desiderata for such a system can only be satisfied if either there is one voter with whose vote the result has to coincide or the result is indifference to all candidates (i.e. they all come equal first, or last). After some general discussion of electoral systems, a proof of Arrow’s Theorem will be given for a special, but not very special case.  The mathematical background required for this talk is quite modest, and it will be suitable for students.