Graph convolutional networks (GCNs) are powerful tools for graph-structured
data. However, they have been recently shown to be vulnerable to topological
attacks. To enhance adversarial robustness, we go beyond spectral graph theory
to robust graph theory. By challenging the classical graph Laplacian, we
propose a new convolution operator that is provably robust in the spectral
domain and is incorporated in the GCN architecture to improve expressivity and
interpretability. By extending the original graph to a sequence of graphs, we
also propose a robust training paradigm that encourages transferability across
graphs that span a range of spatial and spectral characteristics. The proposed
approaches are demonstrated in extensive experiments to simultaneously improve
performance in both benign and adversarial situations.