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Language: en

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[Music]

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At the very early stage

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[Music]

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I wanted to be a scientist. So, 

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the field was not defined and maybe when

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I was 14 I would have thought I

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would be

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like an archeolog or 

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trying to read this

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cuneiform plates from Iraq to

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understand what

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they were talking about. But of course, I

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found it more realistic to do mathematics

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after the baccalaureate and

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then I understood it was

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very interesting to do mathematics.

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And because precisely I was in this

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university system, which was less

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selective than the

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propriety school we have, at

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some point

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in the second year I found that the

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professor in mathematics

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was a little bit too shallow and too

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slow. So then I decided to do

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my own mathematics, and I found

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in the library

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a book, written by a well-known

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mathematician in France, which is

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named Dieudonne, and he was one of the

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main

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members of the Bourbaki group. And one of

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the people who wrote

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most of the texts written by Bourbaki, so

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very pure and

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very abstract mathematics. But for some

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reason

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the same person had written a textbook

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for students

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on the topics in analysis and in a

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completely different style.

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I never understood actually

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what was his motivation.

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In the book, which is called

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Calcul Infinitésimal,

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there were a lot

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of exercise to be done,

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without solution and without

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indication.

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And I found exciting to try to solve

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these exercises by myself.

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So without the professor, just from the

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book,

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and this was almost like a research

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program, because all these exercises were

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difficult

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and without any hint or solutions. So, I

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remember I spent

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the summer vacation trying to solve

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these problems,

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and this was really exciting and so I

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got really the excitement for

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mathematics

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during this summer. So for me, the

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excitement started when I was 18 I would

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say.

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Before, I was much more excited

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by the comparison

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between old languages, like

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Sanskrit, Greek

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or Icelandic. I was much more

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fascinated by that.

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Mathematics is beautiful, but mathematics

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is much more important than people think,

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because it's behind so many things. And

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of course, for the good and for

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the bad.

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If you are pessimistic about the

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progress, you can say, well this is a

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dangerous game, but

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I would say: If you're optimistic

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it's

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fantastic. I mean it is

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remarkable how mathematics were powerful,

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and they started the modern western

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civilization

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in a remarkable way,

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of course there were many drawbacks also.

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The starting point for me was

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a strange meeting I had

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in the Atomic Energy Center in France.

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Because I was working in the

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computer science institute of France,

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which is called Inria,

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and so in this institute was supposed to

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do really a interaction with concrete

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problems, and once we had a meeting with

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some people from the Atomic Cnergy

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Center in France,

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and these people are taking care, not

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only on the

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nuclear plants, but also on the

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nuclear bomb.

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So, something happened in the 80s,

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you may remember that the France was

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still launching

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some atomic bomb in the Pacific Oceans

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in some atolls,

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which was extremely controversial. At

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some point

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the idea was to put the bomb inside

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the atoll. That atoll is the top of

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a volcano, which is

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just slightly above the sea level. It's

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very flat, like two meters high

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and once, because of the explosion, there

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was

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a landslide on the side of this volcano,

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which created a tsunami, and the atolls

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were almost entirely flooded by that.

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So these people were very nervous about

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the free mechanic

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simulation

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of the tsunami, how a very flat area

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can be completely devastated by

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a tsunami.

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For some other reason I had been

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interested in the

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computational approximation of

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free motion,

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and for some reason I had some

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idea about solving the problem, which was

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not very

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concrete. In some sense this was more

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like

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I think in German you say "Gedanken". I

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mean, this is like

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a way of thinking of the problem,

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and I was not really successful in

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helping these people.

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Just after the meeting I was

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fueling some new ideas

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in my mind, and then, by thinking about

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this problem,

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I end up with

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this interaction you described between

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the different fields of mathematics.

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Because this was the optimal

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transportation

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field, known by statistics and

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probability,

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but it was

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essentially unrelated

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to my own field of mathematics, which is

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like partial differential equations and I

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bridged

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and also made the connection with this

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equation of wind motion.

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So for me it's very natural, the link was

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very natural, but for some people it was

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very surprising.

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How can we put together so

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different things

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and motivated by a kind of, I would say

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more or less not so nice, a military

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application. But

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somehow, I was very satisfied that I

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could get

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a lot of theoretical idea out of that,

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but at the same time I was not unhappy

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not to solve the problem.

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I think I was very lucky because

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essentially I don't remember any big

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trouble.

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I was very lucky actually.

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I would say the opposite, so I could tell

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you

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how many times I was very lucky, I think

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it's more relevant.

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So I think I was very lucky in making

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this strange

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choice at the beginning, choosing the

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university instead of the grande ecole,

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because I think this helped me in some

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sense in many aspects.

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Also, I was very lucky in doing...

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So actually, I benefit from bad events,

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one of the bad events was this oil

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crisis, that moved me to

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applied mathematics, and I think it was a

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good decision. Also,

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I had to do the military service as we

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did at that time in France,

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and actually I

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managed to go to

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this overseas service, which was a

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possibility

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of substituting for the military service

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in France. I was a kind of

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researcher in Mexico, and then I met

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a very well-known numerical analyst from

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the USA,

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Stanley Osher from UCLA, and then

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this started the connection with the USA

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through

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the University of California. This

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was really helpful, because this helped

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me also in my career.

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The fact that, at some point, I moved

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from Paris to Nice in a research

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position was very

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good to me, because this gave me

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more freedom.

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I had a professor position that

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I enjoyed very much, but then this was a

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nice continuation 

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to do research in the beautiful city of

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Nice, which was

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a little bit reminiscent of California

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for me. So

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actually, it's more like a succession

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of luck. I don't remember...

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[Music]

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Okay, of course, when you remember things you

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typically wipe out the

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difficult parts, but I think I was really

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lucky, maybe my generation was lucky.

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For instance, we didn't have to go

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through this postdoc position, that now

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the young people have to do.

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So I got a research position to do my

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PhD actually.

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So it was a temporary position, but I was

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hired

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with a contract of seven years to do my

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PhD to continue research.

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If you think about the modern condition,

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we are very far from that.

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Maybe in France some people managed to

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get research position at a very early

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stage,

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but this is very exceptional at the

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world level. This is due to the

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CNRS, the institution I belong to, the

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Centre National

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de la Recherche Scientifique, and I'm very attached

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to this institution,

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which is quite getting really unique in

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the world I would say.

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Which is able to provide stable position

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to people at the early stage.

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So my advice for a researcher

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[Music]

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would be to keep some strong

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personality, and

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to avoid to be too much a follower. You

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know, because this is...

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It's probably a wrong advice, I'm

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saying,

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because it is certainly the most

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profitable thing to do, to 

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be in a good field with

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very good leaders in mathematics and to

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be a follower of them.

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But I would prefer

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to advise to stay

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free as much as possible, and to try to

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open

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your own track of research. Not to

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be too influenced by

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the community, and the problems.

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Maybe it's a pessimistic view, I have a

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feeling that nowadays people are already

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constrained by a lot

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of strange rules, like

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contracts and things like that. They

00:10:25.200 --> 00:10:29.440
are pushed to be

00:10:27.680 --> 00:10:30.880
against independence, I think

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very much so.

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Anything that could prevent people to

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depend on the

00:10:35.440 --> 00:10:40.720
organization managers, I think would be

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good. I would like that

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people, the young people,

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at the collective level would fight to

00:10:45.440 --> 00:10:49.519
preserve

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the independence and not to be ruled by

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crazy

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management requirements.

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[Music]

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I cannot tell you so much, because I

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don't think there is any planning

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actually.

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This is also something that maybe

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the management of some doesn't understand

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enough.

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That it's very hard to plan

00:11:11.440 --> 00:11:15.440
actually in this business.

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So, if you are too much planning,

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it's a bad sign in my opinion.

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The planning should be quite

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limited,

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because you should be ready to shift

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to some other idea

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quite swiftly at any time. But of course,

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since I love computation, I would be

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really...

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It's not planning, it´s more like a

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dream. If I could be

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heading a methodology

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to solve some big computational

00:11:44.320 --> 00:11:47.920
problem in the field I like,

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I would be really happy about that, but

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this may be too much a dream. So I'm more

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related to theoretical studies than that,

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but I would be very proud to

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design a new algorithm

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[Music]

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for many possible applications. This

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is something that is always

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driving me.

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[Music]