Interview with a mathematician: Nassif Ghoussoub

Nassif Ghoussoub is the founder and current director of the Banff International Research Station, the founding director of the Pacific Institute of Mathematics, and the co-founder of MITACS NCE. On top of all that, he is an award-winning mathematician, whose most recent work focuses on differential equations and mass transport theory.


I met Nassif when he was Scientific Director of MPrime NCE. My first impression of him was that he was amiable, laser sharp, and a natural leader. I’ve read his blog Piece of Mind for years, where he posts refreshingly blunt (but fair) views on the academy.

Nassif was recently inducted into the Order of Canada, which is an honour he very highly deserves. I think we should all be proud as Canadians to have a mathematician of his stature represent us in Ottawa and on the world stage.

During the interview, Nassif was warm and open. I find the way Nassif talks about mathematics and the creation of the PIMS and BIRS truly inspiring.


AB: Congratulations on recently receiving the Order of Canada. How did that transpire, and what was the experience like entering the Order?

NG: A few weeks before Christmas of last year, I received a phone call from the Governor General’s office. I was asked if I would accept to be an officer of the Order of Canada if appointed by the GG. First, I thought it was a prank. How can one refuse such an honor? It was a big surprise. I was ecstatic. For me, it is a huge deal, mostly because of the way I came to this country. I was essentially a refugee, though I didn’t enter Canada as a refugee. Two months before I was about to defend my doctoral thesis in Paris, a civil war broke out in Lebanon—my home country, where I was planning to go back, teach at the university, and be with my family. I came instead to the US as a post-doc, to wait the civil war out, then to Vancouver, where UBC had offered me a position. The war didn’t end until sixteen years later. By that time, I was a fully-fledged Canadian with a Canadian family. I feel blessed.

Nassif receiving the Order of Canada from Governor General David Johnston.

Besides giving me refuge, Canada allowed me to contribute. My friend Ivar Ekeland (a former president of Université Paris-Dauphine, who eventually came to be director of PIMS) told me once that I couldn’t have done in France what I have managed to contribute here. He has lived both the Canadian and French contexts, and he is aware how closed and rigid the system is in France, while Canada has so much potential to move forward. All that we need here is more people able and willing to participate in building this great country. The opportunities are incredible. Just look at the Trudeau government with its young cabinet ministers, some of whom are relatively recent immigrants.

I’ve had accolades in the past, but for me the Order of Canada was really special. This is the country where I lived the bulk of my life. I developed so many friendships over my forty years here. Another enjoyable byproduct of this honour is how it triggers a flood of congratulatory messages from so many of them, reminding you of the many awesome people you’ve known at various stages of your life.

AB: What was your path to becoming a mathematician?

NG: I read your interview with Ken Ono, and it was striking to me how different our paths to mathematics were. We do have a somewhat similar refugee background, but Ono was born into a mathematical family, and was immersed in mathematical culture. His father was a serious mathematician.  I come from a small mountain town of mostly farmers (Beit-Chebab) in the Levant. My parents didn’t have a chance to even finish high school. They married very young and had to leave right after World War II to western Africa to make a living. Very early on, however, they wanted us to get an education, so they sent me back to Lebanon with my siblings to Christian boarding schools, when I was only three years old. I didn’t have the cultural or family background to even know what mathematics is all about (as opposed to arithmetic), never mind advanced research in mathematics. I was fascinated by Euclidean geometry, then by calculus, but I didn’t know what advanced research meant until I went to university in France.

In high school, I was subjected to the old French system with drills, problem solving, and tough, frequent exams. I was considered good at it—at least relative to my classmates, and got a scholarship to study in Paris. But, when I got there, I had to deal with a new reality. Some of my graduate contemporaries were simply amazing, enough to let you doubt your own abilities and wonder whether you are good enough for such a career. Of course, it was much later that I realized that these graduate students were to be the world’s best, such as Fields medalist Jean Bourgain, but also Michel Talagrand, Gilles Pisier, Bernard Maurey, and other future stars. Luckily, I stuck with it, and worked very hard to be able “to simply belong”. I say luckily, because now I realize that Mathematics essentially saved my life (literally). It got me to Canada, and earned me the wonderful life and family I now have.

AB: Who were the mathematicians or teachers who inspired you most in your career?

NG: For my last year of high school (equivalent to grade 12 or 13), I had to leave my mountain village to join a public school in Beirut. That was a first reality check. I thought that “I was good”, until I met this amazing non-conventional teacher. I still remember his name (the only one I remember from high school): Moufid Said. The guy challenged us, provoked us, and essentially insulted us whenever we erred in our mathematical reasoning.  He would state a problem on the board and we had to race each other to solve it. For him, it was competition. His teaching methods defied any pedagogical theory, even then. First, we hated it, then it started growing on us. These were the late sixties. A long time ago! I was only fifteen then. That’s when I started enjoying problem solving.

As with most families within my community, parents wanted their children to be physicians, lawyers, or engineers. I was preparing to get into medical school, when I randomly encountered my very same high school teacher, Said, on a Beirut street. He asked me about my plans, and I told him I was going into medicine. And here he was again in his overbearing, take no prisoner way: “If students like you are not going to do mathematics, I don’t know who else would do it in this country”. To the chagrin of my parents, I went to do a Bachelors of Mathematics. I wonder sometimes how many of our life changing decisions are really ours, and how many are byproducts of random circumstances.

In France, I was inspired—and awestruck—by celebrities like Laurent Schwartz, and my supervisors Gustave Choquet and Antoine Brunel. They were giants in their respective fields then, members of the fabled French Academy of Science, and the whole works.

AB: You’ve worked in a variety of areas ranging from functional analysis to non-linear analysis and partial differential equations. Would you give us a summary your current research focus?

NG: I seem to be as restless in my mathematics as in other aspects of life—whatever this means. My areas of interest evolved many times, influenced either by colleagues or by the pull of interesting problems. I started in Functional Analysis, which is somewhat a conceptual field, and then I switched to Partial Differential Equations, which is a very technical field. Lately, I have been drawn to the Theory of Optimal Mass Transport, which essentially combines both features.

This theory started with a problem formulated by Gaspard Monge, who was a Chief engineer in Napoleon’s army: What is the optimal (least costly) way to transport a pile of rubble from one place to another. This mundane looking problem has had a fascinating history spanning more than two centuries, including a major contribution by St Petersburg mathematician, L. V. Kantorovich, who applied it in economics for which he won the Nobel Prize. Another Russian, V.N. Sudakov, announced a proof in the sixties, which was eventually found lacking in the 2000’s. The field is very active, with people considering various cost functions for different applications.  For example, the case when the cost is proportional to the square of the distance travelled, turned out to be very seminal in fluid dynamics, for functional inequalities, for differential geometry, and for PDEs. My most recent interest is in the so-called Optimal Martingale Mass Transport and its applications to financial mathematics.

Image result for Gaspard Monge
Gaspard Monge (1746-1818).

AB: You have been one of Canada’s top mathematical leaders with involvement in PIMS, MITACS and Mprime NCE, and of course as Director of BIRS. What drives you forward in these ventures?

NG: In my first fifteen years in Canada, I was just a “normal” faculty member. By “normal,” I mean, minding my own career, very possessive of my research time, avoiding committee work, travelling the globe to work with my co-authors all over. In 1994, I joined an NSERC grant selection committee, and for the first time, I started interacting with other mathematicians in different parts of the country, learning how the system works, and how mathematics was treated at NSERC compared to other disciplines. That’s when I realized that there was a lot of work to be done in Canada and for Canada.

For one thing, we had many excellent Canadian mathematicians, yet limited resources and opportunities for them, mostly due to various states of ignorance by university administrators, industry leaders and government agencies, as to what mathematics can do. There was also a big gap in opportunities and resources between Western Canada’s mathematical science community scattered in a large and relatively isolated geographical area, and those in Southern Ontario (served by the Fields institute), in Montréal (supported by the CRM), and with easy access to the mathematical Centres in Boston, New York City, and Chicago. We wanted to link the scattered universities in our vast region to the rest of the (mathematical) world. That was the idea behind the creation of the Pacific Institute for the Mathematical Sciences (PIMS).

I was very green, but I had enthusiasm and was fortunate to have a wonderful group of colleagues to work with: Ed Perkins at UBC, Reinhard Illner at University of Victoria, Claude Laflamme, Peter Lancaster and Michael Lamoureux in Calgary, Nicole Tomczak-Jaegermann, Bryant Moodie and Bob Moody at University of Alberta. Arvind Gupta, the late Jonathan Borwein at SFU, and his brother Peter were a huge influence. As you wrote in your blog, Jon was a major asset: a great source of innovative ideas, energy, and political savvy.

PIMS was probably the very first distributed institute in the world. That was then a futuristic idea, only made possible by a recent advent of e-mail communications and the Internet. We were trying to create meaningful links between mathematical scientists in a geographic area that was bigger than Western Europe (with BC, Alberta, and Washington State). We also connected mathematicians with the industrial and educational sectors. Now that looks like obvious things to do, with PIMS being one of the most successful mathematical science institutes in the world, encompassing fourteen universities and two countries. But these were novel ideas for that time, and funding was hard to come by. I have a whole shelf in my office of unsuccessful proposals to NSERC, BC and Alberta governments between 1995 and 1999.

As soon as NSERC awarded PIMS a reasonably functional grant in 1999, I felt that with Fields and CRM, we may now be well positioned to apply for a Network of Centres of Excellence (NCE). The idea looked bizarre then, for many reasons. For one, our proposal pitching mathematical methodologies to address societal issues was to compete for government funding in “the big league” of high-profile, disease curing, deep universe exploring, big science projects. The network was to have a totally different mandate than the institutes, including getting the private sector to realize that mathematics was important for their bottom line. We were fortunate that Don Dawson directed the Fields Institute at the time, and Stephen Halperin chaired the Mathematics Department at the University of Toronto: two close friends who cared deeply about the future of Canadian mathematics. Together, we worked on the first proposal for MITACS, and the rest is history.

AB: Like many mathematicians my age or younger, I grew up with BIRS and the institutes. But it’s fascinating to hear how they all came to be.

NG: In the fall of 1999, I went on sabbatical to France to rest from all this, and to get my research back on track. I had been to Germany’s Oberwolfach before, but it was while visiting CIRM in Marseille, that I had the idea to develop a similar Centre in Canada. This was a bizarre idea then, since a panel commissioned by the US National Science Foundation had asserted a year earlier that there is in no need for such an institution in North America. I begged to differ.

Besides falling for the spectacular geographic location of Banff, and the place of high culture that The Banff Centre represented, I personally felt that Alberta was the ideal province to host a major mathematical Centre with a mandate that complements MITACS and the other institutes. After all, Alberta’s government, its mathematicians, university administrators, and community leaders had played a key role in establishing PIMS and MITACS. And sure enough, thanks to a great Alberta science and innovation enabler, Bob Church, the provincial government was the first to pledge funding support. On the other hand, I felt the time was ripe to have a true partnership with the US, both on the operational and institutional level. So I contacted my friend, David Eisenbud, the Director of MSRI in Berkeley, who quickly embraced and supported the joint initiative. Within six months, BIRS was funded! PIMS had taken essentially five long years, and here, lining up the support of three granting organizations serving three different governments (Alberta Innovation, NSERC and NSF) took just six months!
The Banff International Research Centre.

And here, I must give lots of credit to Tom Brzustowski, then president of NSERC. Tom is a mechanical/aeronautical engineer, a former provost of Waterloo, who had a clear understanding of the role of mathematics in scientific discoveries and engineering innovations. He proceeded to break every taboo of the NSERC bureaucracy by asking his Vice-President Nigel Lloyd to accompany me to meet the NSF officials in Virginia, and carry NSERC’s message: Canada is open to scientific collaboration between the two countries. I say taboo, because NSERC’s modus operandi is foreign to the notion of initiating, incubating, or even expressing early support for research initiatives. It is focused on reviewing and potentially funding formally submitted proposals via rigid bureaucratic processes. This feature is very relevant to current discussions in Naylor’s review panel on how to fund “big science” in a Canadian context. How to initiate big multinational, multidisciplinary projects, and who speaks for Canadian science on the international stage?

Tom Brzustowski was the President of NSERC from 1995 to 2005.

Mexico joined the partnership a couple of years later, and more recently CONACyT provided major funding to build and run Casa Mathematica Oaxaca (CMO), which now hosts some of BIRS research activities. So BIRS was a major development on many levels. It is the first real and ongoing scientific partnership between Canada, the US and Mexico. It is truly international, both operationally and institutionally, and everyone “pays their share,” so to speak. The NSF covers US scientists, CONACyT supports the BIRS programs in Oaxaca, while European and other countries contribute substantially by covering the travel of their citizens to Canada and Mexico. The four granting agencies review BIRS on a regular basis by organizing joint site visits. We just had another successful one and I am happy to announce that the funding is secure for another 5 years cycle.

AB: You’ve been an outspoken critic of university administration, in particular with regards to events surrounding university presidents and boards.

NG: Sometimes I wonder if the biggest mistake of my life was to serve on the Board of Governors at UBC. I was there for six years (2008-14). Once you are there, you are exposed to how decisions are taken, how hundreds of millions of dollars are spent, how mistakes (honest or not) are made. Universities are becoming huge, profitable businesses here and in the US. And whenever you have large sources of cash, the vultures start circling: construction companies, developers, IT companies, energy outlets, athletic gurus, and the emerging merchants of sustainability and the green economy. It is incredible. As a mathematician, you can reason, compute, scale and estimate. So you start being exposed to some unpleasant things. And once you get to know so much, you cannot ignore what is going on around you: the good, which is welcome, but also the bad and the ugly, which give you heartburn and sleepless nights. I wish sometimes that I kept the blissful ignorance of a regular faculty member—at least of that side of a university. It was a great learning but painful experience.

AB: What do you think the role is of faculty in holding university administration accountable?

I, like most faculty members, have my own vision of the university as a place of research and learning. That’s why the university was created at the first place. The curse of UBC was that its president has to also be the mayor of “University Town”. When you sit on the most expensive real estate in the world, this creates lots of opposing pressures: Are we a university or a Club Med for students on the Pacific? And when you approve capital projects, you have to make choices between maintaining old and decrepit academic buildings, or building state-of-the-art aquatic centres, stadiums, tennis and squash courts, or commons.

I know you must be alluding to the short presidency of our colleague, Arvind Gupta. Well yes, I was involved in that search committee having been elected to represent the faculty. UBC has so many resources, and if used right, we could lift the university and all of Canada to great heights. But we needed academic priorities to come first. Gupta’s agenda was to refocus on the academic mission, so we had high hopes.

Things went bad for various reasons, and I knew more than most because for one, I had mingled with the main characters on the Board, the Executive and the Deans, including those responsible for the president’s resignation. I didn’t think it was fair either for UBC or for Gupta. But I became an outspoken critic and I blogged about it, mostly so that such an institutional failure never happens again. The university governance needed to be reformed and taught to Board Chairs, Chancellors as well as Deans. How much can the Chair of the Board—who doesn’t necessarily know about academic matters—interfere with the working of a university? Should the Board micromanage the President? Can the Deans make end runs and turn to Board members whenever they disagree with a president’s decision? It’s really about the future of UBC. If we don’t fix these governance issues, then no president will be able to preside

The faculty revolted, and 800 of them eventually voted non-confidence in the Board. That was huge, even if they are trying to ignore or downplay it. The outcome of all of this, is that, we the faculty, strengthened the Presidency, which duly represents the academic side of university governance. Ironically, there is traditionally, an “us versus them” mentality between the administration and the faculty. Here, we had a reverse situation, where the faculty supported the role of the President to make tough academic choices and define the priorities. Because of that, we now have Santa Ono, a president with a strong mandate. We expect him to use it, to reform, to refocus on the academic mission. But for that, he needs a major sweep of all the characters involved in last year’s fiasco. Otherwise, he would be rewarding those who trampled on university governance and stalled UBC for many years. We are hoping he will do that sooner rather than later.

AB: I think it’s important for a President to have an academic background. They should be members of the academy.

NG: Absolutely. That’s a given—at least for me. But unfortunately, I’ve also seen our own academic colleagues sometimes going into administration and adopt that us vs. them mentality. Just look at the actions of the interim president who replaced Gupta, vis-à-vis academic freedom and the Jennifer Berdahl affair (which is yet to be settled in spite of the Smith report and the resignation of the Board Chair), vis-à-vis sexual assault on campus, and divestment from fossil fuels, etc. The best way is to work with faculty and work with them as partners. Faculty can be easily disarmed—if you will—once they know you are looking out for the best of the university. Santa Ono is so far doing very well in this direction. Arvind was a reformer. He may have proceeded too fast, and perhaps he didn’t have a deep understanding of university politics, of historical entitlements, power brokers’ expectations, and turf borderlines. But the painful episode exposed the risks of having non-academics or/and those unfamiliar with the academic mission, run the show at our universities. The Board is currently reforming its governance structure, and I hope these issues will be front and centre in their deliberations.

AB: You are active on social media: Facebook, Twitter, and your own influential blog Piece of Mind.

NG: I came to blogging in a random way. I was sick and bored in bed, so I started typing on my laptop and I never stopped. But in the back of my mind was also the fact that I owe it to the faculty who elected me to the UBC Board, to tell them what are the big issues facing the university, and my own position on them. Then some NSERC issues arose, and I became vocal about that too. Eventually, and perhaps because I was saying aloud what many Canadian researchers were thinking, the blog became very popular, attracting thousands of hits for each post. I heard that political parties were distributing my posts in their weekly briefings to their parliamentarians, especially on things related to NSERC or government funding for research. I realized this is useful! It surely was, especially when governance issues exploded at UBC. However, it’s a big responsibility and a huge investment.

Nassif’s blog, Piece of Mind.

I joined Twitter to advertise my blog. Facebook is more recent: my daughter opened an account for me, and people I knew forty or fifty years ago started to reconnect with me. Every medium is interesting in its own right. President Ono is all over Twitter. And I bet his social media blitz is putting pressure on Deans and other Presidents to join. Otherwise, they will look as secretive, isolated, aloof, and non-transparent as they’ve ever been. I think this is going to become the new way for accessing administrators, but also for holding them publicly accountable. I think it is positive. The only problem is how to manage time. You have to limit and control this. If you solve this problem, let me know!

AB: What do you think is the importance of blogging and social media for mathematicians in the 21st century?

It’s important to communicate to inform and involve the new generation. Hopefully, they will take up the baton. As far as I am concerned, my advocacy stems from my own belief that Mathematics is one of the deepest, most powerful and useful research disciplines. I am absolutely convinced that the depth and breadth and sophistication of mathematical research is second to none. This is my starting point. Unfortunately, it is not so for many—scientifically illiterate—administrator and bureaucrats. Try to explain the Langlands program. I want our community to be more confident of its business and I want it to show its self-confidence. Without this view, mathematics will not thrive in Canada or the world.

Mathematicians should also learn about, and compare their resources to those of, other sciences. Young researchers need to know for example how, owing to inflationary pressures, BIRS had asked NSERC for an additional $75,000 above its previous grant. That was rejected because the math envelope is frozen. It has been for years. 2,200 scientists converge on BIRS each year, and an additional 800 go to Oaxaca (30% of those are Canadian). Yet, the federal government provides the fourth lowest fraction of the BIRS budget ($2.6 million per year) after the NSF, Alberta and CONACyT. They need to compare this to what transpired with the recent CFREF announcements: More than 1.2 billion dollars given to a dozen projects. There is something wrong in this picture, and a new generation of researchers has to get involved to get government and decision makers on their side.

Here is another one of our challenges as a community.  As soon as a mathematical line of research becomes useful to another discipline or to innovators, it stops being called mathematics. The first generations of computer scientists were all mathematicians. They founded the first computer science departments in the late sixties. Now CS is a giant discipline that dwarfs ours. The whole new economy is based on “mathematical instruments”, but uses different names to brand those: analytics, cryptography, artificial intelligence, and data science. All of these are offshoots of mathematics. The same goes with the so-called pure mathematics. Think of how topology and its byproduct, quantum topology, enabled the recent Physics Nobel winners. Watching the chair of the Nobel committee explaining topological invariants with pretzels and bagels must be a familiar sight to many of our undergraduate students. They know but most others don’t. Social media should allow them to spread that gospel.

AB: I’d like to close with looking forward. As Director of BIRS, you have a bird’s eye view of many breaking trends in mathematics. What would you say are some of the major directions for mathematics in the future?

NG:  It is mind-boggling to see so many emerging areas of mathematical research developing at such an exponential rate. As of last week, BIRS received a record 210 proposals for its 2018 program. Now we have thirty outstanding mathematical scientists on the BIRS review panel, yet you would be surprised how many blind spots we have: new mathematics and new applications that none of us had heard of before. All of science is evolving at a rapid pace, but mathematics is at the forefront of this race for knowledge.

To answer your question, I have to first mention the remaining classical big mathematical questions popularized by the one million dollars prizes of the Clay Institute. It is remarkable to me that the Fermat and Poincaré conjectures have been solved in my lifetime, but not the regularity of solutions to the Navier-Stokes equation or the P=NP question. Is it because the answer to the latter problems will turn out to be negative? I personally believe that the Riemann hypothesis is the Holy Grail, and is in a class of its own.

Image result for sciences
“Mathematics is an amazing human endeavour that is at the very core of our quest for understanding, discovery, and progress.” -Nassif Ghoussoub.

But there are many—less classical and even more challenging—mathematical issues that will be occupying the next generations of mathematicians. I say “issues” because they are not distilled yet to the level of becoming specific “problems.” The most frequently mentioned query is whether mathematics can be as successful in biology as it has been in physics, for example, what are the Fundamental Mathematical Laws of Biology? In the same spirit, can we develop a mathematical theory to build a functional model of the brain that is mathematically consistent and predictive rather than merely biologically inspired? Not unrelated is Mumford’s call for new mathematics for the 21st century that captures and harnesses “stochasticity in Nature”. Finally, the advent of powerful computers, and the need for more powerful computational power has again placed mathematical techniques in a central position in science and technology. This is particularly true of the computational and algorithmic aspects of mathematics, but it pertains as well to techniques of modelling, analysis, and simulation. Mathematics is an amazing human endeavour that is at the very core of our quest for understanding, discovery, and progress. Most people are still not aware of it, and that’s why we have to keep telling our story.

Anthony Bonato


11 thoughts on “Interview with a mathematician: Nassif Ghoussoub

  1. Reblogged this on Piece of Mind and commented:
    In this interview, Anthony Bonato got me to reveal quite a bit about my background, my path to mathematics, my role in founding the Pacific Institute for Mathematical Sciences (PIMS), the MITACS Network of Centres of Excellence, and the Banff International Research Station (BIRS), my years on the UBC Board of Governors, my position on Arvind Gupta’s “mandatus interruptus,” my impressions on UBC president Santa Ono’s first steps, as well as my take on social media, and the future of Mathematical research. A bit long, but hopefully not very boring.

    Liked by 3 people

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