Pop, goes the sound.
Soap bubbles transform into countless droplets, splashing iridescent foam under the sunlight, free and unrestrained.
This barely perceptible sound has been captured multiple times by Thierry De Pauw — a genius-like eruption of ideas in his mind.
Formerly a professor of mathematics at Paris Diderot University (now Paris West University Nanterre La Défense), De Pauw has long been engaged in research in mathematical analysis, making significant contributions to the field of geometric measure theory. One of his main research topics is exploring the geometric complexity of soap films and soap bubbles, particularly in infinite-dimensional spaces.
It's not just him; ordinary soap bubbles have long fascinated several generations of mathematicians.
In early 2024, Professor Thierry De Pauw joined the College of Science and the Institute for Theoretical Sciences at West Lake University on a full-time basis, assuming a mathematics professorship, and establishing a research group focused on geometric measure theory.
Thierry De Pauw at West Lake University provided an image
Two books about bubbles
Thierry De Pauw's journey into the realm of bubble mathematics seems like a culmination of random events.
It all started with encountering a math teacher who had an appetite for the subject. He became intrigued by the idea of "proving the obvious," particularly in the context of geometric proofs, still engaging in the traditional method of illustrating and explaining on large sheets of paper, just in a more rigorous and systematic manner.
In 1988, as a high school student, De Pauw participated in a math competition and won an award for the "most elegant proof." The award ceremony had a peculiar twist, with a variety of prizes laid out for the winners to choose from. When it was De Pauw's turn to pick, there was only one book left on the table.
"It looks like I don't have much choice," he said, without a doubt, it was a math book. More specifically, it was a book about the mathematics of soap bubbles and soap films.
That was his first encounter with this ancient mathematical problem.
"Before this, I never thought about discussing bubble blowing in the language of mathematics."
After graduating from high school, De Pauw enrolled at the Catholic University of Leuven. The first two years of his university courses were busy and traditional, until his third year when a "peculiar" teacher joined the class.
It was an elective course, and the teacher arrived late, appearing as if he had just come out of a bathhouse with damp hair. Instead of rushing into the lecture, he presented a theorem for everyone to prove, while he paced around the classroom, intermittently observing and pausing.
"This is simply the hardest mathematics," De Pauw thought.
That notion only lasted until the end of the class. Because the "peculiar" teacher suggested that for today's topic, they could find a book in the library—a book about soap bubbles, a "book of mysteries."
Once again, the ancient mathematical problem of soap bubbles surfaced.
"Look, this is the second 'coincidence'," De Pauw went to the library and borrowed the book. "Over 600 pages, the content is challenging, almost incomprehensible for undergraduates."
Despite its difficulty, he read it and grew fond of it.
When it came time to write his thesis in his final year, he didn't know where the courage came from, but he chose this "terrifying big book" to consult with his advisor. It was a struggle, facing rejection several times, only to realize that even the advisor who directed him to the library to find the book wasn't an expert in this field. "It's beautiful mathematics, but I can't guide you," was the most common response.
One advisor agreed to supervise him, but with a disclaimer: "I don't research this, but since you're interested, go ahead and give it a try."
De Pauw was ecstatic. To this day, he remains deeply grateful to that advisor.
Writing the thesis was incredibly challenging.
Later, the advisor provided some funding for him to travel and meet scientists who studied bubble problems, who could help answer his questions.
The rest of the story is that Thierry De Pauw graduated from the Catholic University of Leuven in 1993 with a Bachelor of Mathematics degree. After obtaining his Ph.D. in 1998, he went on to postdoctoral training at University College London, Rice University in the United States, and the University of Paris-Sud (now Paris-Saclay University) in France. In 2002, he returned to his alma mater, the Catholic University of Leuven, as a researcher for the Belgian French-speaking Community Fund for Basic Research. In 2008, he was awarded the Jacques Deruyts Mathematical Analysis Prize for the years 2004 to 2008 by the Royal Academy of Sciences, Letters and Fine Arts of Belgium, and that same year he accepted a professorship at the University of Paris 7 (now Paris Diderot University).
Approach the process with "curl", and the results with "Buddha".
De Pauw's student years were spent like this, and now he demands the same of his own students: "Hurry home and study hard."
"Whatever you do, you have to master the language to write poetry; otherwise, you'll only produce clichés." To put it in Chinese terms, to do a good job, one must first sharpen one's tools.
But before finishing the sentence, the following one sounds even harsher: "Prepare for failure."
"Being extremely tolerant of failure should be the biggest difference between mathematicians and others," De Pauw offered a solution. "If you can't solve a problem, move on to the next one first, it's better than sitting in a corner crying."
Thierry De Pauw's Classroom: Unrest at Heart
In early February this year, just before the Chinese New Year, Thierry De Pauw joined West Lake University full-time.
Hangzhou was his first encounter with China. In 2008, he was invited to attend an academic conference there, marking his first visit to the country. Back then, he was moving from Brussels to Paris to take up a professorship, and China was just a minor episode.
Sixteen years later, he chose Hangzhou to continue his research on "bubbles."
What changed?
"The most important thing is time," De Pauw says. "Having time to work, time to research, time to think. As a researcher, that's what I should be doing."
West Lake University provides professors with ample academic support, with the most crucial being time—professional administrative teams handle time-consuming and tedious administrative and paperwork tasks.
"It may sound trivial, but it's really quite different."
De Pauw has always been at odds with time.
At the age of 14, when high school required students to choose between science and humanities, he had his own ideas. "I liked math, and I liked literature, so I wanted to learn both." No one at the school had encountered such a situation before; balancing the demands of both science and humanities required a significant time commitment, and many courses clashed. How could one child manage it all?
But he insisted on learning, just like he insisted on writing that paper on "bubbles."
He insisted on learning, just like he took philosophy courses alongside mathematics in his first two years of university.
Time, he always finds a way to make it work.
"Fortunately, the high school teachers agreed, I don't know how they managed it," De Pauw says. In a rapidly changing world where every student's personality, strengths, and needs are different, adapting to these changes is much easier in a new school or institution—there are no fixed rules, no labels; you can become who you want to be.
And that's what attracted him to West Lake University.
"Being part of something new is incredibly exciting, but it's also bound to be a bit scary and hesitant, but that's innovation, isn't it? I'm more curious about what will happen next," De Pauw says.
What will happen next?
In this small yet vibrant campus, he will seek out more people interested in "bubble" research.
Finding people at West Lake University is the most common and easiest thing to do. An academic corridor connects the School of Life Sciences, the School of Sciences, and the School of Engineering from west to east, covering everything from cellular microcosms to engineering marvels reaching the skies and seas, to AI algorithms in black boxes. He also plans to organize international academic conferences, inviting mathematicians from different research fields to discuss innovative ideas together.
"I've roughly outlined six or seven research directions, each pointing to different branches of mathematics," De Pauw says, counting on his fingers. "I can't possibly know everything. What I know is just a tiny, tiny part of science, so collaborating with people from different academic backgrounds, educational backgrounds, and cultural backgrounds is crucial—they often have very different ideas."
"The essence of mathematics lies in its freedom." On Thierry De Pauw's personal homepage, he regards this quote from the mathematical genius Georg Cantor as his guiding principle.
