These are the show notes for episode 9 of the Travels in a Mathematical World Podcast. 9 is prime and excluding 1, for which the case is trivial, 9 is the smallest number which is equal to the sum of the digits of its square. More about the number 9 from thesaurus.maths.org.

This week on the podcast is the first of two installments from Dr Adrian Bowyer, who talks through some of the areas his career has taken him into. You can find out more about Adrian from his homepage at the University of Bath, and Adrian has a Wikipedia page.

There is a reasonable introduction to stick/slip at Wikipedia. Adrian’s article in the Computer Journal (downloadble here but not free) proposed what became known as the Bowyer/Watson algorithm. Find out more about Geometric Modelling at Bath here. You can read an introduction to Boundary Representation here. Here is an applet which models Pólya’s Urn Experiment.

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

UPDATE 14/03/09: Obviously 9 is not prime. I’ve published a blog post highlighting my error: 9 is an experimental error.

Why do you think 9 is prime?

That is an exceptionally good question. I can’t imagine what happened there!

There are two worrying elements to this: First, why did I say “9 is prime”? Second, why have 295 people downloaded the file before someone has pointed it out to me?

Oh dear, oh dear…

I’ve published a blog post highlighting my error: 9 is an experimental error.