Clara Stegehuis searches for patterns in large networks

Clara Stegehuis, Professor in the Mathematics of Operations Research group, is an expert in the areas of probability theory and stochastic networks. ‘My main line of research is large networks, such as the internet, social media or the brain,’ she explains. ‘I investigate large networks using probability theory. This can help us determine, for example, how virus spreads across a network or - to give a more cheerful example - to study how and why memes spread across social networks.’

Studying networks involves many mathematical questions, but it can also lead to many different applications, stresses Stegehuis. ‘Networks can be very big, but they are made of small connections – so called edges. To make it easy to imagine: on social media, these small connections are represented by friendships between individual users. We can search for patterns in these connections, and those patterns might reveal something meaningful about the network. They can help us reveal bots, fake users that might be set up to spread fake news, for instance. More frequent patterns can signify something strange is happening within the network. But then the question is: what do we consider normal and what is abnormal? That is a mathematical question and something that I look into. This can be applied also to neurological networks in our brain. We can use it to quantify what is normal and what could potentially be problematic.’

Clara Stegehuis was awarded the VENI grant for studying this very topic. She received the grant for research on ‘understanding subgraph patterns in high-dimensional networks’. In other words, for investigating patterns in networks and quantifying when a pattern is normal and when it appears too often. ‘The big question I work towards as a scientist is understanding how these small connections and patterns appear and how they relate to the overall network. It’s not only about quantifying, but also about understanding the why – why do they appear in the first place,’ she says.

While most Stegehuis’ research relates to many different networks, she also specifically studies internet networks and their resilience. ‘I look into how resilient internet networks are to failures. At what point is failure truly harmful and can lead to a large internet outage? Knowing this can help us come up with a better strategy to improve internet infrastructure.’

## Education

Besides research, the UT scientist is passionate about teaching and communicating her research field to a wider audience. ‘I really enjoy showcasing all the different types and applications of mathematics,’ says Stegehuis. ‘The math we learn at school only shows a very small part of mathematics and I want to show everyone how interesting the field can be. Mathematics has so many applications most people never think of and I believe that everyone could find an aspect of mathematics which they like. People often respond with “But I’m not good at math.” You don’t have to be good at something to appreciate it. I can’t paint, but I appreciate art. I want people to see that mathematics really serves a purpose.’** **

## About Clara Stegehuis

Clara Stegehuis is Professor at the Mathematics of Operations Research (MOR) research group at the University of Twente’s faculty of Electrical Engineering, Mathematics and Computer Science (EEMCS). In 2020, she was awarded the NWO Veni grant (250.000 euro) for research on ‘understanding subgraph patterns in high-dimensional networks’. In the same year, she also received Netsci NL Young Talent prize and the UT Professor de Winter prize, an international publication prize for top female talent. Stegehuis is active in communicating her research to the general public. She was also one of the KNAW `Faces of Science’ and often gives public lectures, for example at high schools or theaters.

## Press photos

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