Graph Neural Networks
In many applications in data science, such as social networks, chemistry, recommendation systems, knowledge graphs, traffic networks, and functional brain networks, the data is represented by graphs. Graph neural networks (GNNs) extend classical deep learning methods to graph-structured data and have achieved resounding success in the past few years. By now, GNNs are ubiquitous both in industry and in the applied sciences. Since graphs are irregular objects, graph neural networks present challenging problems, such as how to define convolution on graphs, how to train a network on certain graphs and apply it to other graphs, how to define a convolutional network that is stable and robust to domain perturbations, and how to determine the expressive capacity of graph neural networks. Contemporary research focuses on such questions, which span the spectrum between theoretical analysis and application.