Monday 14 December, 2009

20 08 2009

Numbers: From -1 to 2 raised to the power of infinity

Presented by Dr Daryl Cooper, University of California, Santa Barbara


One cornerstone of mathematics is the concept of number. We learn in primary school that when you multiply two negative numbers the answer is positive. A few years back a prominent columnist claimed that this was wrong and that the answer is really negative. We will start by explaining why the answer is indeed positive. This explanation illustrates a key stepping stone for tonight’s lecture: all numbers are abstractions. From here we will explain exactly what infinity is, how to do basic arithmetic with infinity, why there are different sizes of infinity, and why 2 raised to the power infinity is always bigger than the infinity you first thought of!

Two lessons come from this. First one must have a very  precise understanding of a concept before trying to reason about it. Second, and perhaps most importantly: advanced mathematics is full of amazingly beautiful and intriguing ideas, some of which are far crazier than the weirdest science fiction, or the most bizarre hallucinations. However these ideas are as real and certain as that 2+2=4.

  • Time: 6:30pm to 7:30pm (Doors open at 6pm)
  • Venue: Ithaca Auditorium, Brisbane City Hall
  • Refreshments: There will be complimentary drinks and nibblies following the talk, and Daryl will be available to answer any questions.
  • Questions? Contact Lynelle (l.ross@smp.uq.edu.au)