*From EWM Newsletter n°22 (2013/1)*

*Christiane Rousseau studied at University of Montreal where she got her PhD in 1977. After postdoctoral studies at McGill, she came back to University of Montreal where she became professor. During her whole career, she led in parallel research activities and outreach activities: lectures in the schools, organization of mathematical camps, and articles in mathematical magazines. She has been President of the Canadian Mathematical Society from 2002 to 2004. Since 2011, she is Vice-president of the International Mathematical Union. When she was Director of Centre de Recherches Mathématiques in 2013, she started the initiative “Mathematics of Planet Earth 2013 (MPE)”, which now has the breadth of an international year under the patronage of UNESCO.*

**EWM: How did you come to have an academic career in Math?**

CR: It came quite naturally. I had always been interested in mathematics. When I finished my postdoc, it was a period with very few academic positions in mathematics. At that time in Canada the Natural Science and Engineering Research Council was concerned that universities could not plan for the future. It created a program of five year research positions in universities that could be renewed provided the universities committed to hire the candidates as professor at the end of the first five term mandate. I was one of the first recipients of these awards.

**EWM: Can you shortly describe your research field and your most important results in this respect?**

CR: I work in dynamical systems, mainly in the analytic context, and I concentrate my work on dynamical systems depending on parameters. Local methods allow to study the neighborhood of singularities, and bifurcation methods allow to explore the behaviour near singular values of the parameters (bifurcations). There are very few global methods for analyzing dynamical systems, but fortunately, singularities and bifurcations very often organize the global dynamics. To study singularities and unfolding of singularities, one uses normal forms. The normal forms are often simple but, most often the changes of coordinates to normal form diverge in the analytic context. My main results are in the direction of explaining why these normalizing transformations diverge, in terms of geometric obstructions to bring the system to the normal form. These obstructions are often only seen when one extends the variables to the complex domain and unfolds the system.

**EWM: How has the MPE event evolved from the planning phase to date? How do you manage as an organizer of such a big event?**

CR: Originally, MPE2013 was a North-American venture, mostly centered on scientific programs to be organized by the North-American institutes, even if I always had in mind to also include an outreach component. Indeed, I had the idea of MPE2013 in 2009 when I was Director of Centre de Recherches Mathématiques (CRM) in Montreal, and North-American institutes are naturally networking. But, MPE2013 spread by itself. When we learnt of the interest of Institute Henri Poincaré (IHP) and Isaac Newton Institute (INI), we decided to enlarge the initiative to the world. The initial two years were mainly focused on the planning of scientific events: long term programs and workshops. Now, MPE2013 has the breadth of an international year under the patronage of UNESCO. The outreach component has become very important with tenths of public lectures and activities for the schools in many countries. An international Open Source Exhibition was launched during the MPE Day at UNESCO on March 5 2013, and this exhibition will grow during the coming years.

While MPE2013 has a North-American Steering Committee, its structure is very flexible. MPE2013 has no budget as such: the MPE partners commit to organize MPE activities and bring the budget for them. MPE2013 provides the website for the initiative. The American Institute of Mathematics (AIM) has been very helpful in the organization of MPE2013 with hosting two planning workshops in 2010 and 2011, and now hosting the website. The Mathematisches Forschungsinstitut Oberwolfach is hosting the website of the MPE Exhibition.

**EWM: MPE has had a huge impact in Mathematics not only on the research side, but also on the teaching one. Can you tell us more about the influence of MPE on Maths teaching?**

CR: I would say that the influence of MPE2013 on the teaching side is still to come. The success of MPE2013 comes from the fact that it is so timely: it makes the link between the tools that mathematics can provide and the planetary and societal challenges. Some type of activities will only occur in 2013, but some aspects of MPE2013 will last. This includes the teaching. A lot of people are excited with MPE2013, but they miss resources to integrate MPE examples in their teaching. It takes time to develop new examples and exercises, from one hour capsules to chapters, or courses or even academic programs. But any material developed for this purpose will last for several years, and the website allows to share the material within the world mathematical and educational communities. We already see new academic programs around MPE matters in preparation around the world.

**EWM: What can you say about the fundraising for MPE (notable successes, difficulties) in which you or colleagues from the organizing committee were involved?**

CR: As I mentioned before, MPE2013 has no budget as such. So we did very little fund-raising ourselves. Of course, many of our partners made fundraising for their own activities. In the US, there were two major successful applications to the National Science Foundation (NSF), one for a series of MPE workshops in 2013, and one for what is now called MPE2013+, i.e. MPE activities past 2013. In particular, the second grant provides money for maintaining and expanding the website past 2013. A special budget was needed for the organization of the MPE competition, and for the organization, jointly with the International Mathematical Union (IMU) and UNESCO, of the MPE Day at UNESCO and of the launch of the MPE Exhibition on March 5, 2013. North American partners provided the funds to support the competition, while IMU and European partners supported the MPE Day at UNESCO. Mathematisches Forschungsinstitut Oberwolfach has provided enormous in-kind support for installing the MPE Exhibition on the Imaginary Platform.

**EWM: Applied Mathematics is clearly very well represented within MPE. What about Pure Mathematics? Does MPE have goals that emphasize the role of the very theoretical aspects in everyday life?**

CR: It is clear that Pure Mathematics is less represented in MPE. But I consider that it is there. While a pure mathematician is not always interested in applied problems, most of us are concerned with planetary problems and, as scientists, we want to understand the underlying science. I am myself a pure mathematician, and I am fascinated by all the subjects that I learn when working for MPE2013: in fact, it is one of my rewards for all the work I put in the project. And, looking at it from outside helps me have a global view of all the different topics that fit under MPE instead of limiting myself to some special subjects. There are MPE plenary lectures at mathematical congresses and also MPE colloquium talks that are very interesting for pure mathematicians. The French and English daily blogs are also very nice. I like to see mathematics (and science in general) as a continuum with no rigid boundaries between pure and applied mathematics. And some MPE topics are really borderline between pure and applied mathematicians. This is the case for instance when one applies the methods of the n-body problem and dynamical systems to the movements of the planets and artificial objects orbiting around our planet.

**EWM: What is it that you like most about MPE? What are your hopes/expectations regarding the impact of MPE on society at large and on encouraging women to pursue mathematical studies?**

CR: As I mentioned before, MPE2013 is spreading by itself. While I had the initial idea, MPE now belongs to the community. And the spirit of MPE: collaboration around the world, networking with other disciplines, mathematical research on planetary challenges, enrichment of the curriculum, is there to stay. I am personally very committed to the training of future high school teachers and to popularization of mathematics, and it is very exciting to see the enthusiasm in the schools and among the public for the new image of mathematics that is brought by MPE.

Another important goal of MPE2013 is to attract a new generation of researchers to the planetary problems. For that purpose, it is important to highlight the mathematical questions or challenges hidden behind these problems. The theme is very creative: there are so many topics that can be related to the planet. Hence, I hope that this will be attracting to women who will follow my dream when I started MPE2013…