For the second episode of Teacher Talk, we had the honour to talk to Mr. Brinkhuis, mathematician and professor at ESE. He received his PhD in mathematics at King’s College London in 1981 and later joined the Econometric Institute of Erasmus University.When we arrive at his office, located on the 10th floor of the Tinbergen building, he kindly offers us some coffee and we sit down to ask him some questions.
What kind of music do you like?
I like rap a lot for a very special reason. In the past, my son went through a period in his life - he was about 16 - where he didn’t take anything seriously. You couldn’t talk to him about anything, except one thing: rap music. Of course, as a father, I wanted to have some serious conversations with my son, so I started listening to rap music. At first, it was a rather repetitive noise to me, but then, after talking to my son and listening to him, I saw the structure that was in it. Now, I am a big fan of rap and I can determine the quality very quickly.
Some years ago, I had a quite serious accident and I couldn’t give lectures for a while. After a while, the doctor said I had gotten better and I could try lecturing again. However, when you give lectures to three hundred students, you need to be able to keep them in check. That was never a problem, but after the accident, which resulted in some brain damage, I wasn’t sure whether I could do it.
But then, during a holiday in Poland, I was in a taxi and in a flash, I saw a poster on a wall that read “Kendrick”. Now, for me, there’s only one Kendrick and that is Kendrick Lamar. I couldn’t believe my luck when I found out Kendrick Lamar was giving a concert. To me, he is the greatest rapper in the world. I managed to get tickets and not long after, I was among thousands of Polish people at his concert. I had planned to stay silent, but everyone was jumping up and down and after a while, so was I. Afterwards, I was sure that I could give lectures again. Plus, I also really enjoyed the concert.
What are your main interests in research?
My main interest is optimization. A special focus here is convexity and convex problems. A couple of years ago I had an idea to reduce everything to cones. A colleague of mine, Tihomirov - a famous professor in Russia - told me that this would not work, because cones do not have a rich enough structure. The structure was too poor to build everything on cones. Nevertheless, I managed. He was very happy about this and I’m currently writing a book about it.
My whole family had to suffer though, because the only thing I could talk about was rap and cones.
My whole family had to suffer though, because the only thing I could talk about was rap and cones. They even gave me a Spanish lamp in the shape of a cone, which is still in our room.
What do you expect from students for the course Matrix Algebra?
They should do lots of problems and fill pages with formulas. Whether you can solve the exercises or make mistakes or write absolute nonsense, it doesn’t matter. Learn from a bad example, like me. I used to be a very arrogant student. I understood subjects like Matrix Algebra very easily, so I was too lazy to do exercises. Later, I regretted this a lot, though. It is one thing to understand what you read, but another to actually solve problems yourself.
Who is your biggest hero?
In mathematics, my biggest hero is Tihomirov, my co-author on one of my publications. In life, however, I do not have any special heroes.
What is the strangest thing that has ever happened to you as a lecturer?
There was something that happened at the beginning of my career, when I was not yet experienced. I was teaching students in economics and some of them were not paying attention during the lecture. Instead, they were throwing a tennis ball around, which resulted in me getting hit by it in the head. They did apologise afterwards, though.
What are your hobbies?
My greatest hobby is reading books. I do not usually find Dutch books to be that good, but one of the best was written by one of my students, Ernest van de Kwast. He always used to be a funny fellow. I remember the first time I came to the lecture; he was listening to music. I told him to turn the music off, because you are not allowed to listen to music in class. He told me no, because it was still before time, and that I had no right to say anything to him. I immediately knew he had a strong character. So, if you every want to read a funny book in Dutch, read “Mama Tandoori”. I have never read anything as good as that book in Dutch.
What did you want to become when you were three years old?
Back then, I had two ideas, both of which didn’t work out. First, I wanted to become a sailor. I lived in Amsterdam and we crossed the IJmeer. I liked that so much that I decided to become a sailor. Later, I changed my mind and wanted to become a musical clown. Though, when I went to school, I found out I wasn’t very athletic, when we had to do a koprol (forward roll) in PE. So, clown was also out of the question. At that time, I did take it very seriously. I wanted to make music and make people happy.
What’s something that students don’t know about you?
I like it very much when students recommend a good book to me. Especially because my students come from so many different countries, so if they would all recommend a writer or a book, that’d be great! Last year a few students from Albania advised me to read Kadare, so I read some great books written by him. Apart from reading books, I also like watching TV series. I try to watch all the good ones, no matter the genre.
What genre do you like?
All. I like all, but especially – although, this might be because I’m Dutch – I like French books, because they’re cheap. There are a few bookshops in Paris, where they know me by now. The first time I went there, I looked for someone who looked like they read themselves. I had read French books written by famous writers, like Baudelaire and Jean-Paul Sartre, but I never got to read something that wasn’t so well-known. So, I approached this woman and I asked her which books she’d recommend to me. She admitted that she wasn’t really familiar with male taste in books, so then I said: “Let’s have the female taste then.” The most important thing for me is that a book is of good quality.
What’s the publication you’re proudest of?
The publication that I hope is still to come.
Do you have a favourite theorem?
Well, there’s one that still keeps me busy. It’s based on the Lagrange multiplier rule, which you use for optimization problems, and you can go further with this. You can optimize a path in time, so you’re optimizing a function. I’m working on it and I hope to finish it this year.
I was standing on top of the Empire State Building, with my klitteband.
If you were a piece of clothing, what would you be?
There’s one piece of clothing to it and I’m quite sentimentally attached to it, because I had lost it for many years. Once, I went to a conference in Princeton and on my way back, I stayed in New York for one day. I wanted to see everything, so my day was extremely busy. It was quite cold, so I was wearing this sort of band around my head, which used klitteband (Velcro tape) to fasten it. I went to the Empire State building and when I wanted to buy a postcard, I put it away for a second, but when I looked back, it was gone.
For many years, I have been searching for it in all the shops in the Netherlands and I couldn’t find it, but last year, I finally did. Now it still reminds me of that happy moment that I was standing on top of the Empire State Building, with my klitteband.