Fortnightly Mailing

A report from Keith Devlin's and Coursera’s Introduction to Mathematical Thinking MOOC

Attempting to prove that the square root of 2 is irrational

I’m six or so weeks into Keith Devlin’s 10 week Introduction to Mathematical Thinking, along with some tens of thousands of others. [NB. I published my second and final report on the course in June.]

Here is a longish thumbnail sketch of the design of the course, followed by two appendices. Appendix 1 concerns peer review. Appendix 2 is what the course web site has to say about grading and certificates of completion.

Comments, questions and corrections would be most welcome.

1. The course is advertised as needing about 10 study hours per week. This is about right: though in my case I had to skimp a lot while I was on holiday, other than wrestling unsuccessfully with a proof that had been set as course work, the non-fruit of which is shown above.

Stretchered off: Hardangervidda to Rjukan

What can go wrong on a ski-trip?

Over Easter this year – with my friends B and A – I did a 9 day hut-to-hut ski-tour running roughly North to South across Hardangervidda, the huge high wild roadless plateau of central Norway, that is bounded to the North by the Hardanger glacier, and to the North and West by the innermost lobes of Hardangerfjord. (At one point the glacier and the sea are less than 10 km apart.)

I did a similar trip in completely different weather and snow conditions in 2008 with B and daughter M (from Haugestøl go Haukeliseter).  This year we started at Hallingskeid on the Oslo to Bergen railway a little East of Finse and a bit before the trains begin their steep decent towards Bergen. For me the trip finished about 2 km short of the road at Haukeliseter after nearly 200 km. (For aficionados our route was Hallingskeid – Rembesdalseter – Kjeldebu – Dyranut – Hadlaskard – Torehytten – Tyssevasbu – Litlos – Hellevasbu – Haukeliseter.)

This Easter, central Norway was blessed with high pressure, leading to sunny, cloudless, cold and largely windless conditions. Lack of snow and previous strong winds meant that there was plenty of lumpy and grooved sastrugi to contend with, and a lot of hard and quite smooth unforgiving and sometimes shiny icy surfaces. And it was exceptionally cold, with -30C on some nights and daytime temperatures of between -23 and -5C.

In the continuation post below are a few pictures from the wonderful trip. But the purpose of this long post is to record what happened when things went wrong. I’m doing this partly to help others better to understand the anatomy of an accident, and partly to get what happened out of my system. What follows is a slightly edited version of something I wrote in Oslo on 1 April on the way home.