# What are higher-order networks?

Networks - as mathematical representations of interconnected units -

are relevant in a wide range of real-wold systems, ranging from

interconnected neural cells in the brain to relationship networks

between authors of scientific articles. Traditionally, networks have

been equated with the mathematical concept of a graph that specifies

relations between pairs of individual units. While this approach has

produced for example powerful tools to analyze data, there has been a

shift to recognize the importance of relations and interactions beyond

pairs, namely relations between more than two individual units.

In the paper *What are higher-order networks?* published recently in

SIAM Review, VU mathematician C Bick and

coauthors take account of these recent developments from a mathematical

perspective. They provide a unified perspective on recent research where

nonpairwise interactions play a role. These range from topological data

analysis to network dynamical systems, thereby connecting different

research directions of interest to the Department of Mathematics at the VU.