These are the show notes for episode 3 of the Travels in a Mathematical World podcast. 3 is prime and the only number which is equal to the sum of all the natural numbers less than it. More facts about number 3 from numbergossip.com.

I was returning home from a trip to Birmingham, when a screen on a Nottingham bus presented me with the following information: Nottingham City Transport runs 320 buses on 67 routes, making 35,602 trips, totalling 236,000 miles every week. As you might imagine, this is a fairly complicated network to model.

In this episode of the podcast, Dr. Joanna Hartley of Nottingham Trent University talks about her career from leaving university and the work she has done with Nottingham City Transport on public transport modelling. If you are interest in shortest path problems, a good overview is available on wikipedia. If you are interested in modelling public transport data, there is an article in plus magazine on Travel-time maps.

You can find out more about my work with the IMA by reading this blog and visiting www.ima.org.uk/student.