Newly appointed professor Wioletta Ruszel investigates the mathematics behind uncertainty

Wioletta Ruszel has been appointed Professor of Stochastics at Utrecht University’s faculty of Science. Her research focuses on developing mathematical tools in order to understand uncertainty and random processes. Stochastics plays an important role in a wide range of scientific fields, including physics, biology and economics. “As a professor, you have more opportunities to shape your field and make an impact, and that’s something I care deeply about. I hope people from other fields will increasingly come to me to chat about what role randomness plays in their discipline. Ideally I might contribute with new ideas and they can broaden my perspective with new applications and challenges.”

Wioletta Ruszel moved from Poland to Germany when she was eight years old. During her first weeks at a new school, surrounded by classmates speaking a language she did not yet understand, mathematics gave her a sense of familiarity and universality. “Mathematics is universal, and I immediately understood what the teacher was writing on the board,” she says. “I was fascinated by its elegance. In a way, mathematics is a very minimalist language. It’s one of my earliest memories of Germany.”

Making an impact

For Ruszel, becoming a professor marks the fulfilment of a long-held ambition. “It has always been my dream to become a professor. I’m incredibly proud,” she says. “As a professor, you have more opportunities to shape your field and make an impact, and that’s something I care deeply about. I hope people will increasingly come to me to chat about what role randomness plays in their discipline. Ideally I might contribute with new ideas and they can broaden my perspective with new applications and challenges. At the same time, I want to help raise the international profile of research in this area.”

Understanding randomness

Ruszel’s field, stochastics, is concerned with the mathematical description of random phenomena, uncertainty and collective behaviour. “What I find fascinating is that so much of the structure we observe in the world emerges from a combination of randomness and some underlying rules,” she says. “That is true for particles at the atomic scale, but also for biological systems made up of many interacting components. If you look closely, things can appear chaotic. But when you zoom out, patterns and structures begin to emerge. How do you describe that mathematically? That’s what I’m interested in.”

Brain cells

“In almost every field, you have to deal with uncertainty,” Ruszel explains. “Whether you are studying economic systems, biological processes or climate predictions, there is always information you do not have.” Stochastics provides tools for understanding how systems behave despite those uncertainties and for making meaningful predictions.

“Take the development of neurons in the brain,” she says. “It is extremely difficult to write down a mathematical equation that describes every individual cell, because the system is simply too large. Instead, you look at the collective behaviour of all those cells. Then you have one equation rather than ten billion, which makes the problem much more manageable.”

In almost every field, you have to deal with uncertainty. Whether you are studying economic systems, biological processes or climate predictions, there is always information you do not have.

Collaboration

Because random processes play a role in so many different disciplines, collaboration is an important part of Ruszel’s work. She frequently works with physicists and hopes to expand those collaborations to areas such as climate science and biology. “I develop the mathematical tools, models and analytical methods that researchers in other disciplines can then use in their own work”, she says.

A shared passion

One of the things Ruszel appreciates most about Utrecht University is the enthusiasm she encounters among colleagues and students alike. “There is a real passion for mathematics and mathematics education here,” she says. “You can have spontaneous conversations about mathematics in the corridor, and people are always willing to help. I also like that Utrecht actively engages with societal and political issues. I find that inspiring.”