Last week there was a conference for Andries Brouwer’s 60th birthday.
Actually he is 60 on 3/4/2011, but we had some lectures to celebrate his birthday on 4/3/2011.
The picture shows Andries at my birthday party in Ambleside in 2007 (which was actually seven months after my birthday), so I was delighted to be asked to participate in his!
Apart from me, the speakers were Lex Schrijver, Chris Godsil, Jack Koolen, and Willem Haemers. Willem presented Andries with an icosahedron (which has 60 angles with 60 degrees in each) and also with a birthday problem about a 60-vertex graph.
I see myself as a pretty good mathematician, a pretty good walker (especially up hills), and a person with liberal views; but Andries puts me in my place in any of these categories. His walking achievements at conferences are legendary, and a glance at his web page will show his concern for open-source software and for freedom of information in general, to say nothing of the huge amount of information on graphs, codes, etc., which are available there. It is no surprise to learn of his contributions to Linux, for example. But there is much more to him, for example his wide and deep knowledge of linguistics.
At the birthday dinner, he told me about his current battle with Springer to establish the principle that an author can be permitted to keep the copyright to his work.
I’m so busy this term that I could only afford a day in Eindhoven. But my relationship with the university and its mathematicians goes back a long way. In the University dining room where the birthday dinner was held, the six versions of the institutional logo were on display; they were still on the second when I visited for the first time. (The most recent change, from TU/e, to TU/e, is by far the smallest. The fourth logo coincided with the change in name from “Technische Hogeschool Eindhoven” to “Technische Universiteit Eindhoven”.)
In the 1970s, when I worked closely with both Jaap Seidel and Jack van Lint, I was a regular visitor. At that time the department had a visitor budget which ran for a calendar year; what was unspent at the end of December went back into the University’s coffers. So I would often get a phone call in early December from Jaap asking if I could come for a week. I would stay with Jaap and Ada; Jaap went on doing and thinking mathematics until late at night, so these visits were both very rewarding and very productive.
On one of these occasions, I ended up with two papers, one with five authors, the other with four, with me as the intersection of the two teams. One of these was the famous “root systems paper”, one of my most cited papers, whose story I intend to tell here one day; the authors other than Jaap and I were Jean-Marie Goethals and Ernie Shult.
Both Jaap and Jack are dead now, but I was very glad to be able to see Jaap’s memorial on the campus, a tree with a concrete post in front of it bearing a plaque.