Portrait: Ingrid Daubechies

Name: Ingrid Daubechies

Nationality: Belgian-American

Profession: Mathematician

We went to Philadelphia Museum of Art, and my son was seven and running ahead. Suddenly he came back, white-faced, and said, ‘Mama, I saw something terrible!’

Baroness Ingrid Daubechies is one of the world’s foremost mathematicians, known for her work on wavelets and image-compression technology. Her research has been used, among many applications, in JPEG2000, in imaging from the Hubble telescope and in authenticating works of art. She was the first tenured female professor of mathematics at Princeton and has won numerous accolades, including recently the L’Oréal-Unesco For Women in Science Award. Here, in our second ‘Portrait’, she shares her drive to promote mathematics, her love of Brussels and her taste for all things ‘quirky’.


Can you give a brief introduction to your journey?

I’m originally from Belgium. I have dual citizenship now and I jumped through a lot of hoops after I became an American to retrieve my Belgian citizenship. I really care about it. Maybe it’s not the case these days, but at the time it definitely felt like the authorities wanted to test whether you were serious about it. You had to assemble a whole lot of documents within a period of three months; none of them could be older than that. I was born in Limburg. I speak Flemish and I’m fluent in French as well because I learned it as a child. My father was one of the few French-speaking Belgians outside Brussels who is absolutely fluent in Flemish, because he grew up in the Flemish part of the country and went to school there because of the war.

At the Vrije Universiteit Brussel (VUB), I got my undergraduate Physics degree and stayed on to do a doctorate. Both degrees were in Physics, so I’m kind of a cheat as a mathematician! I don’t have a math degree beyond the first two years. I did extra courses, extra exams, because I thought I might switch to math, but then I decided to stick with Physics and I’ve never regretted that. All the Physics I learnt has stood me in good stead and I was able to learn the extra math that I need every day on my own.

In 2010, on a sabbatical, I started organising a mathematical contest for Belgian high school students. The idea was that it would help teachers show their students that mathematics is much more than the formulaic things you get in text books. The competition asks questions that are ‘outside of the box’, questions you can’t answer just by rote reproduction of things you’ve learned; it requires mathematical thinking. It’s become very popular and is called Wiskunnend Wiske (loosely translated as ‘Mathematical Mary’) and has its own Facebook page. Schools and classes participate – or even groups of students, they don’t have to be a school. A group of students could get together and participate in that way. Questions are sent to them, and they have a number of weeks to mull them over. Then the classes that do best, forty or fifty, come to Brussels as close as possible to 14 March, which is Pi Day you see (3.14), for the final of the contest. At the same time, they visit Brussels and the VUB and see that it’s not too difficult to go to university to study math.


What was it like as a female student of Physics in Brussels in the 70s?

In Physics, we were 2 women out of 17 students, but many of our classes in the first two years were combined with the mathematics students and at that time there were quite a few young women studying mathematics in Brussels. Many of them were thinking of becoming high school teachers of mathematics. Almost all high school math teachers in Belgium used to be trained in mathematics. I understand that that’s no longer the case, which is a sad thing because high school teaching in the Flemish region was of excellent quality back then, as was borne out by international comparisons. There is a programme called TIMS (Trends in International Mathematics and Science Study) and at that time the Flemish part of the country participated in TIMS and did very, very well, partly due I think to the high quality of teaching.

Now, unfortunately, there are fewer trained mathematicians who go into high school teaching. I’m not saying others can’t teach the material well, but the one thing you do lack if you’re not part of the field is wherewithal, the resources to call upon if a kid doesn’t quite understand something the standard way, or if they have good reasoning but are unconventional, for example. If you think of teaching literature, and there’s a student who resonates especially with one type of literature, only part of the canon, then, because you know literature, you can point them towards something – say Magic Realism, to really keep them engaged. So I think, in history or in language, teachers know how to do that, but in mathematics, if you’re not trained or you’re wary of mathematics yourself, you lose that richness. Also, textbooks in mathematics are very often written in rigid ways with little blue blocks containing formulas, and students think, ‘Oh, I need to know these off by heart’ instead of trying to get to the essence of things.



It’s one of my hobby-horses, so that’s one of the reasons why I thought it would be useful to have the Wiskunnend Wiske contest. We took the comic book character Wiske, and I’m very glad that  the publishers of Suske and Wiske agreed to us using the image. They even drafted some special drawings for the contest. Dutch is one of the few languages in which the name for mathematics doesn’t have that ‘mathema’ root. If you think of German or French or English or Italian or Spanish, it’s always ‘mathema’ but in Dutch it’s ‘wiskunde’ which was a name coined by Simon Stevin, centuries ago. The character ‘Wiske’ is an emblematic cartoon figure and many of the book titles are alliterative… so the name Wiskunnend Wiske was perfect for the contest. Plus, I wanted to encourage more girls because, with fewer people studying mathematics to become high school teachers, the number of women has dropped. It’s still higher in Belgium than in neighbouring countries, but it’s not as high as it could be. Actually when people say, ‘Oh maybe there are fewer women in mathematics because it’s just not “women’s thing”’, I ask them to look at the percentage of women in mathematics in academia across Europe. The percentages differ enormously, which shows it’s a cultural thing because our genetics don’t differ that much. The map of Europe really helps me make that case with American colleagues.

It’s cultural in many ways. There’s the general culture in a society which holds that those maths, science or engineering jobs are not ‘good jobs for women’ or that somehow women aren’t suitable for that work. When, as a result of this, young women don’t see many others in mathematical professions, they worry – maybe these are jobs where it’s not as easy to combine a family and a career. A lack of role models has consequences. For instance, how many female plumbers have you seen in your life? I’ve only seen one and when I met her I realised she was the first. No one would suggest, I don’t think, that women are not suitable to be plumbers but, because there are so few, it’s something girls don’t think of doing.

The other thing is, in the States and many other countries, we are actually graduating many more women than we see reflected in academia. I think what happens is, you have choices as a mathematician where you go and the culture and role models influence those choices. There’s ample evidence that small things are said that make a difference. People don’t even realise that they betray a bias, but many of those micro-aggressions – and I say that although they’re not meant as aggressive necessarily by the people who say them – the micro-aggressions give you pause. If you don’t feel comfortable, why would you stay there? Why would you not go to a job where you feel better and valued? I think culture everywhere matters – in general society and in sub-communities – in attracting and retaining women. I have a very cynical friend who says, ‘The number of women you find in a given country in academia in mathematics, is inversely proportional to a kind of weighted average of how much money you can make there as an academic and how much prestige your job has. Look at Portugal,’ he says. ‘There, you don’t make a lot of money; you don’t have a lot of prestige. Tons of women. Look at Switzerland: lots of money, lots of prestige. Almost no women.’ I haven’t tested that theory out, but at least anecdotally it seems an explanation.



Why Brussels and what were your first impressions of the city?

When I was due to go to university, my father was working in two different locations, commuting between Antwerp and Brussels, and my parents decided that he could just as well commute in the other direction. So, we moved to Brussels and I still lived at home when I went to the Vrije Universiteit Brussel.

It was the first time that we had lived near a big city and to be honest, during my undergraduate years I didn’t explore much of Brussels. Although my parents had moved to Brussels, they hadn’t really studied the transportation very well and I had to take three consecutive buses and trams to get to the campus. Classes started at 8 am, and I would get up a 5.45 am and take a bus at 6.17 am. Classes finished at 5pm or 7pm, so I didn’t have that much time to explore. But as a graduate student, I moved out of home, so there was more opportunity.

I like Brussels. I liked Brussels before, but it’s become much more live-able now. There are many little corners that have been spruced up. I find Brussels a really funky place. It was always a place where you could find a lot of different types of good food but culturally, now, it’s also a very fun and funky and diverse place.

Even though I went to the States for a post-doctoral appointment, I thought eventually I would continue my life in Belgium. I came back and had tenure with NFWO (Nationaal Fonds voor Wetenschappelijk Onderzoek). Then I met the man who’s now my husband, who was in Belgium for a three-month visit. When we decided to get married, I applied for jobs in the States. He promised me that if I couldn’t get used to life in the States, we would apply for jobs together in Europe, but it turned out that was unnecessary.

I still have very strong links with Brussels. I go back to the VUB often and my parents still live near Brussels in Woluwe Saint Stephen and I visit them a lot. They are elderly and a bit frail, so there are many reasons to return.


Could you draw some parallels between other countries where you’ve lived and Belgium? What is similar, what is not? How did the differences you encountered change you?

I first came to the US as a post-doc, so I was 26 and at that time I couldn’t afford to go back to Belgium very often; tickets were very expensive, so it was a year before I returned. It was during the Reagan years, and I knew that when I came to the US that there would be aspects of life that would be different. I expected to be shocked by some things. At that point, for example, there weren’t as many homeless in Europe and there were quite a few in New York. I was shocked by that.

But what I had not expected at all was that I would have a culture shock going back to Belgium. There were things that I had surreptitiously gotten used to in the States. Like many Belgians I know, when I first came to the US, I was a little bit turned off by what I thought was the superficial friendliness, the ‘Have a nice day’, ‘How are you?’ and so on. When it’s just people saying that in a store, many Belgians think, ‘Oh my God, they are forced to say this, even if they don’t feel like it. It’s so degrading.’ But that’s the Belgian take on it. The people doing those jobs don’t think, ‘I’m degrading myself.’  Yes, they’ve been asked to be friendly and they try to be friendly. True, they haven’t thought deeply about how profoundly they wish you, personally, a really nice day. But just trying to be friendly makes the person doing it feel better as well. So they get a little benefit out of it themselves! It’s just something that helps lubricate things. And that’s not at all how I perceived it, but then I went back to Belgium and experienced the less friendly Belgian attitudes again I thought, ‘Oh my God! Why are these people so difficult with me? Why do they go to this extra effort to spoil their own day and mine?!’ I would never have thought that, if I hadn’t had the American experience. Of course, it turns out neither perception is completely accurate: it’s complicated, but it wouldn’t even have occurred to me to reflect on it at all, if I hadn’t left Belgium.

So, I think the whole world would be better if, at this impressionable age where you’re a young adult, you had to leave for somewhere else. If there were a way to make people really realise what diversity means; not just see the Other but have a long enough immersion in a culture so that you can understand. I don’t know how you do that and maybe it’s one of these ‘do-good’ impulses that are decried as not possible. But coming to the US certainly made me realise for the first time, there are choices you make in a culture. Some of those Belgian choices I still like. I like the European preference regarding food, for taste over looks. It’s the opposite in the States where the food might look more impressive, but the ingredients don’t taste as good. I notice the quality of the ingredients every time I go back to Belgium, and I’m talking about in the supermarket; it’s not like I’m going direct to the producer. So, there are choices that every culture makes, and it’s about knowing that they are choices and that things don’t have to be that way. Cultures evolve also. That’s what older people always say: ‘It used to be different.’ Yes, it used to be different and some things were better and some things were not.


Do you gravitate towards people of similar culture to yours?

When I hear people speak Dutch, I may introduce myself, whether they are Belgian or from the Netherlands, and when I know people are Belgian, I try to make a link, but I don’t really seek them out. I haven’t started a Belgian Club here. In museums too, I feel linked to Belgium. My son was very struck by the existence of the Flemish Primitives and that there was a time when Belgium was at this high point, culturally, in Europe.

When the children were little, together with a Dutch friend, we sewed a costume for Sinterklaas, and found a Belgian or Dutch man who would play Sinterklaas. At that point, I found all the Dutch-speaking children in the neighbourhood, even people I knew only by sight at the time, and I said, ‘Look, we have this Sinterklaas and it’s more fun if there’s more kids.’ So, the parents would buy the presents themselves. We gave them a cap of $20 and Sinterklaas would come in with his big bag. At the time, there was not yet the same sensitivity in Europe about blackface as there is now, but even so, the sensitivity existed in the States, and we didn’t want to get into that at all, so we never had a Zwarte Piet.

But my kids believed. In fact, my daughter believed in Sinterklaas for much much longer than in Father Christmas. Everyone had told her about Father Christmas, but Sinterklaas she saw every year, and nobody at school had told her because they didn’t know, so they couldn’t debunk it for her. When she was 12 or so, I was convinced she knew and we promoted her to be Sinterklaas’s helper and she was crestfallen. She was 12! There’s no kid I know in the world at 12 who still believes. Then she embraced it and insisted that we keep doing it until she left for college, because she liked it so much. We had a big book and ahead of time, parents would send us all the ‘good things and bad things’ and Sinterklaas would read it out and call up the children. So we did that, but we didn’t go into the whole ‘saint’ thing. We went in for the food! I was not brought up with a religious framework. I’m an agnostic and I didn’t bring my children up within a religion. I explained to them about religions, but we don’t really observe religious festivals apart from a Christmas tree, because I think that’s great fun.

When I was at Princeton, my parents came over and we went to Philadelphia Museum of Art, and my son was seven and running ahead. Suddenly he came back, white-faced, and said, ‘Mama, I saw something terrible! There was this incredible painting and they were torturing somebody. They had nailed him to a wooden construction!’ And I thought, he doesn’t know! I had grown up with these Christian images and I was much older when I started questioning them because I had always seen them, but he hadn’t. To him, it was a revelation – this suffering person. I mean, why would they paint this?! So I explained. In the middle of the museum, I sat him down and said, ‘There’s this thing.’


How many times a year do you return to your country? Why? What do you enjoy doing?

I’ve always come back to Belgium at least once a year, but now I’m back more often. There was one year I came back about ten times for my parents. but right now I come back every two or three months. We also communicate via Skype.

Brussels is so much smaller than New York. Brussels is more the size of Boston. And I know parts of Brussels so much better. So I don’t really compare them, but I enjoy Brussels and, of course, not being there all the time, I try to discover new things. Walking around, looking. I have subscriptions to The Bulletin and read it online, and if I’m there for special festivals I like to go. Last year, I was there for a sabbatical for six months. The first six months of 2018, we lived in Brussels and we enjoyed it hugely. We took the tram where you can have a gourmet meal. It was a lot of fun: you look out the window and you say, ‘Oh that’s where we are!’ and the meal was excellent. It’s a fun experience. I really enjoyed it.

All things Belgian resonate with me. When I go back to Belgium, I feel it’s home. I like traditional Belgian foods. There’s a cookbook which was quite successful, called ‘Everybody Eats Well in Belgium’ by a Flemish woman (Ruth Van Waerebeek), who lives in the States. She shares her grandmother’s recipes. I’ve given it as a present to people when they come to my house. If they like what I’ve cooked and it’s a close friend, I’ll buy them the book.


If you were mayor of one of the 19 Brussels communes or if you were Minister-President of the Brussels-Capital Region, what would you do as your first action?

That’s a question I can’t really answer! Just the idea of being Mayor of anything would be so frightening to me. I mean, in my profession I have done quite a bit of ‘service’. I was President of the International Mathematical Union and so on, and I see it as service. The one thing I did not like about it was the political aspect. Trying to get people with strong personalities and different points of view to reach a positive outcome. Just the sheer idea! It’s not my talent and I don’t want to get into that again.

I think a strong point of Brussels is its diversity for a town of its size. London or Paris you expect to be diverse, but Brussels is much more diverse than you expect and I think that’s great. So, I’d look for ways of embracing that… and Brussels has many ways of embracing it. Ways of dealing with ‘allergies’ that people might develop, like xenophobia. I think that’s a big challenge everywhere. I mean, I live in the States where there is a President who is encouraging that. I think it’s important not just to counter it but to look at initiatives that have worked. That’s the problem. You may well have goodwill but, because people’s reactions come from complicated roots, emotional connections in many ways, there are some well thought-of initiatives that don’t work and others that do. So trying to study that is important. We need to learn much better how to do that.

I do believe in education. That’s my big bias. I believe that through education you can really show that talent can be anywhere. Fostering it and helping it to develop is a way in which you open people’s eyes, in different groups.


Do you have any anecdote about Belgians, about Brussels?  Or an example of “Belgium surrealism”? 

My husband is British. When we met, he was in Belgium for three months. He had the impression that Belgians got up every day thinking that today might be the day they would have a traffic accident and it would not be their fault. They imagine an accident and their first question is not, ‘Was anybody hurt? Are you okay?’ but ‘Was it your fault?’ Because the big thing is, will the insurance cover you or not? So, he was puzzled by the aggressive driving.


One day I said, ‘What happens if I die first? My deposit box will be blocked and you won’t be able to get your things out of it.’

Also, inheritance laws. If there’s a little bit of wealth in the family, almost everyone I know in Belgium, tries to find strategies to hide some of it from the government for inheritance. At least, it used to be like this. I don’t know if it’s still the case. I told my mother I didn’t want to do this, so we don’t have anything to do with that sort of business, but at one point, my mother had rented a safety deposit box in a bank, and I had the box right next to it. So in my box, for which she had the key, she would put things that belonged to her. She would rehearse me on what was in there, and what I was supposed to do. But I would make fun of it all, and one day I said, ‘What happens if I die first? My deposit box will be blocked and you won’t be able to get your things out of it.’ She turned to my husband and said, ‘If Ingrid should have an accident, you must let me know immediately so I can go to the bank.’ And my husband said to himself, ‘Is this mother really telling me that her first reaction on hearing her daughter has died would be to go to the bank and open the deposit box?!’ So, it’s very surreal. Of course, if that were to happen, I’m sure she would not have reacted that way, but just the fact that she imagined doing it, is striking.

There’s a disregard for rules. I attribute it to the fact that Belgium became independent very late, so people don’t feel as much allegiance to Belgium as a governmental power, as people in the Netherlands or France might do. Food is another example. By and large, the food is better in Belgium than in the Netherlands because Belgium was the battleground of Europe for so long, if you have some money and you have a good meal, they can’t take that away from you.

I have friends who were building a house, but they discovered that if you had a top floor that was not yet accessible by a staircase, you didn’t have to pay the extra value-added tax for that top floor because it was clearly not inhabitable. They had small children who had their bedrooms up there, but money was a bit tight and they couldn’t pay the taxes, so they decided they were not going to have a staircase. They had this ladder, which they pulled up when it was not in use. But because their children were small, of course, they had to put a lot of security measures in place. They had a trap door and so on to make sure it was safe. And they would do this every evening, pull up this ladder, rather than just pay the VAT! They postponed having to pay it and did it later. I mean, that’s a surreal Belgian situation. It’s amazing. I can’t imagine it happening in England, but in Belgium people thought, ‘That’s ingenious!’.

I have a friend who says the Belgians fall somewhere between Germanic and the Latin culture, with the worst of both worlds, because they like to regulate, that’s the Germanic side, but then they have the complete Latin disregard for all regulations!


What are your favourite shops in Belgium/Brussels?

My favourite shops are very small and idiosyncratic. There was a little potter’s shop downtown but they liked sunnier climes so they moved to Spain. She exhibited and had a few designs that became trade objects for big commercial firms, as well as pieces that were artworks. So we bought a couple of those and were very happy with them.

I love walking through Brussels and discovering funky stores. I’m so sorry that many of the art stores around the southern point of Sablon and up to the Mont des Arts have closed now. They each had their own specialties. One had lots of Delft, one had Art Nouveau and so on. They were not quite as fancy as the galleries on the other side, closer to the Palais de Justice. So I’m sorry to see those stores go. I love going behind the Grand Place, in the neighbourhood where they have African stores but I think they might be waning too now and you can find some of that stuff online; on the other hand, that could be nice too in the sense that the people who have those websites are perhaps closer to Africa so it benefits African people more.


Your favourite Belgian/Brussels specialties?  

I love going to a good cheese store. I have places where I can find good cheese here in the States, but a proper cheese store! Or pastries. I love both the little neighbourhood patisseries where they have one or two things that they do superbly well, as well as the fancy pastry shops like Wittamer.

I don’t particularly like the waffle stands you have everywhere because I don’t think they’re very authentic. There used to be old Liège waffles which I liked, but now it doesn’t appeal to me. Also, people here in the States ask me constantly, what is a true Belgian waffle? Except there’s no such thing: there’s a Brussels waffle and a Liège waffle and the waffles that my grandmothers made. There are zillions of different waffles! And there was a tradition, especially on New Year’s Day, when people would come by and you’d give them waffles. Both my grandmothers made waffles, completely different ones. My mother would tell the story of her grandmother who made waffles on an iron that you heat in the fire, and there were yeast waffles, like in Brussels. But my other grandmother came from the Borinage and she made a sugary waffle that you could keep for a long time. We would take them home in a tin, whereas the Brussels waffles you eat fresh.


Do you have a personal wish linked to Brussels?

I hope to come back on a regular basis and be healthy enough to keep doing that. I hope it continues to become more vibrant and prosperous. We’ve been talking about the way Belgians get around regulations and so on, but I think it’s also linked in some way to a type of tolerance. Yes, there can be intolerant attitudes and we can all cite examples, but generally speaking, this way of getting around regulations means that you accept that things don’t have to be the way that somebody dictates to them to you. And that can sometimes be very positive and I like that a lot. In Flemish, they have the word ‘plantrekker’, for Belgians, people who find a way around things, who find a solution, a way to make things work. Finding ways to make things work can be a very good thing. Recently, because of my mother’s health problems, a friend bought me a book by Tom Lanoye called, ‘Speechless’ (Spraakeloos) in which he talks about his mother who was an amateur actress who loved language but lost her speech through a stroke. The whole book is an incredible story about growing up in a Flemish city. It was so wonderful and Belgian; so accepting of all the ways in which people can have their quirks and be different. That is something that I do miss. I’m not saying people aren’t tolerant in the States, but there’s a way, a Belgian way, that resonates with me and I hope to keep experiencing it. I will buy many more of his books.


Read another portrait: Tim Grosvenor